REPORT

ON

THE MINERAL EXPLORATION

IN

THE ZACUALPAN AREA,

THE UNITED MEXICAN STATES

(PHASE Ⅱ)

FEBRUARY 2003

JAPAN INTERNATIONAL COOPERATION AGENCY METAL MINING AGENCY OF JAPAN

Preface The Japanese Government decided to conduct a mineral exploration program

consisting of geological, geochemical and geophysical surveys in the Zacualpan area, in

response to the request from the Government of the United Mexican States. The

purpose of the program is to estimate its potential for mineral deposits. The Japanese

Government entrusted the implementation of this plan to the Japan International

Cooperation Agency (JICA) and JICA entrusted the enforcement of the program to the

Metal Mining Agency of Japan (MMAJ) due to the specialty of the program. MMAJ

started the survey program in the fiscal year of 2001 and dispatched a three members

survey team to Mexico from September 16 to November 26, 2002.

The field survey program in the area has completed as scheduled in

cooperation with the Consejo de Recursos Minerales and the concerned Governmental

organizations of Mexico.

Finally, We wish to express a deep appreciation for the cooperation of the

concerned Governmental organizations of Mexico and Japan.

February, 2003

Takao Kawakami

President

Japan International Cooperation Agency

Norikazu Matsuda

President

Metal Mining Agency of Japan

Teloloapan

Taxco

Summary

The survey has been performed in the Zacualpan area to estimate the mineral

potential for volcanogenic massive sulfide ore deposits and other types of gold, silver,

copper and zinc deposits, through an interpretation of results of geological and mineral

occurrence surveys.

The survey of this year (phase Ⅱ) includes the geological and geochemical

exploration in Aurora and Rancho Viejo areas, three drilling exploration holes in Aurora

area and geological detail survey in Santiago Salinas area which were proposed in phaseⅠ

survey.

The result of the geological survey has revealed that the Aurora area is underlain

by the Villa Ayala Formation, Pachivia Formation and andesitic intrusive rock.

Furthermore, distribution pattern of upper sedimentary rocks of Villa Ayala Formation

that hosted massive sulfides lens of old mines has been defined.

Geological detail survey in Santiago Salinas area resulted in the identification of

massive sulfide type mineralization and alteration zones on footwall dacite.

Geochemical survey defined several zones of geochemical anomalies in or around

the old mines, west of La Campana, Santiago Salinas etc.

Drill hole MJZC-1 intersected the massive sulfide horizon and footwall

mineralization and alteration zone. Drill hole MJZC-2 intersected the disseminated pyrite

zone in schistose volcanic rocks. Drill hole MJZC-3 encountered the sedimentary rocks

which corresponded to the host sedimentary rocks of old mines.

Rancho Viejo area is underlain by the Villa Ayala Formation and Pachivia

Formation. No significant mineralization, alteration nor geochemical anomaly was found

in Rancho Viejo area. It is judged that the potential for economically valuable ores in this

area is low.

Following promising districts which include significant mineralization and

alteration, hanging wall sediments, and little explored zone, are recommended for the third

year’s program in conclusion of this survey.

1. Santiago Salinas 2. La Campana 3. North of Capire deposit

CONTENTS

Preface

Location map of survey area

Summary

Part Ⅰ The General

Chapter 1 Introduction ････････････････････････････････････････････････････ 1

1-1 The Background and Objective of the Survey ････････････････････････････ 1

1-2 Conclusions and Recommendation of the First Year････････････････････････ 1

1-3 Outline of Phase Ⅱ ････････････････････････････････････････････････････ 2

Chapter 2 Geography of Survey Area ･･･････････････････････････････････････ 7

2-1 Location and Access ･･･････････････････････････････････････････････････ 7

2-2 Topography, Climate and Vegetation ････････････････････････････････････ 7

2-3 Infrastructures ･･･････････････････････････････････････････････････････ 8

Chapter 3 General Geology ････････････････････････････････････････････････ 9

3-1 Outline of Geology ･････････････････････････････････････････････････････ 9

3-2 History of Mining in the Area ･･･････････････････････････････････････････ 9

Chapter 4 Integrated Discussion of Survey Result ･･･････････････････････････ 12

4-1 Characteristics of Mineralization and Geological Structure ････････････････ 12

4-2 Mineralization and the Result of Geochemical Survey ･･･････････････････ 15

4-3 Potential for Ore Deposit ･･････････････････････････････････････････････ 16

Chapter 5 Conclusions and Recommendation ････････････････････････････････ 23

5-1 Conclusions ･･････････････････････････････････････････････････････････ 23

5-2 Recommendation for the Third Year’s Program ･･･････････････････････････ 26

Part Ⅱ Details of the Survey

Chapter 1 Geological Survey ･･･････････････････････････････････････････････ 29

1-1 Survey Method ･･･････････････････････････････････････････････････････ 29

1-2 Survey Result ････････････････････････････････････････････････････････ 29

Chapter 2 Geochemical Survey ･･･････････････････････････････････････････ 97

2-1 Survey Method ･･･････････････････････････････････････････････････････ 97

2-2 Survey Result ･･･････････････････････････････････････････････････････ 98

Chapter 3 Drilling Survey ･････････････････････････････････････････････････ 131

3-1 Survey Method ････････････････････････････････････････････････････････ 131

3-2 Survey Result ･････････････････････････････････････････････････････････ 133

Part Ⅲ Conclusions and Recommendation

Chapter 1 Conclusions ･･･････････････････････････････････････････････････ 173

Chapter 2 Recommendation for the Third Year’s Program ････････････････････ 176

References ･･･････････････････････････････････････････････････････････････ 177

Appendixes

List of Figures

Fig. １ Location map of survey area

Fig. Ⅰ－３－１ Tectonostratigraphic terranes of Mexico ･･････････････････････ 10

Fig. Ⅰ－４－１ The integrated interpretation map ･･････････････････････････ 19-20

Fig. Ⅰ－４－２ Geological model of Aurora area ･･･････････････････････････ 21

Fig. Ⅰ－５－１ Location map of promising districts ･･････････････････････････ 27

Fig. Ⅱ－１－１ Schematic stratigraphic column of Aurora area ･･･････････････ 57

Fig. Ⅱ－１－２ Geological map of Aurora area･･･････････････････････････････ 59-60

Fig. Ⅱ－１－３ Geological section of Aurora area ････････････････････････････ 61-62

Fig. Ⅱ－１－４ Location map of rock and ore samples ･･･････････････････････ 63-64

Fig. Ⅱ－１－５ Location map of ore showings ･･････････････････････････････ 65-66

Fig. Ⅱ－１－６ Geological map of Santiago Salinas area ･････････････････････ 67-68

Fig. Ⅱ－１－７ Geological section of Santiago Salinas area ･･･････････････････ 69

Fig. Ⅱ－１－８ Stereographic projection ･･････････････････････････････････ Appendix

Fig. Ⅱ－１－９ Sketch map of mineralized outcrop in Santiago Salinas area ･･･ 71

Fig. Ⅱ－１－１０ Schematic stratigraphic column of Rancho Viejo area････････ 73

Fig. Ⅱ－１－１１ Geological map of Rancho Viejo area ･･･････････････････････ 75-76

Fig. Ⅱ－１－１２ Geological section of Rancho Viejo area･････････････････････ 77

Fig. Ⅱ－１－１３ Sketch map of mineralized outcrop in Rancho Viejo area ･････ 79

Fig. Ⅱ－１－１４ Harker diagram ･･･････････････････････････････････････ Appendix

Fig. Ⅱ－１－１５ Discrimination diagram ････････････････････････････････ Appendix

Fig. Ⅱ－１－１６ Spidergram ･･･････････････････････････････････････････ Appendix

Fig. Ⅱ－１－１７ Result of X-ray diffraction ････････････････････････････････ 81-82

Fig. Ⅱ－１－１８ Result of fluid inclusion test ･･････････････････････････････ 83

Fig. Ⅱ－１－１９ Result of isotope analysis(δ18O and δ13C) ･････････････････ 87

Fig. Ⅱ－２－１ Scatter diagram of major elements･･･････････････････････････ 106

Fig. Ⅱ－２－２ Histogram of alteration index ･･････････････････････････････ 107

Fig. Ⅱ－２－３ Distribution map of alteration index ････････････････････････ 108

Fig. Ⅱ－２－４ Scatter diagram of minor elements ･･････････････････････････ 109

Fig. Ⅱ－２－５ Histogram of As････････････････････････････････････････････ 110

Fig. Ⅱ－２－６ Distribution map of As ･････････････････････････････････････ 111

Fig. Ⅱ－２－７ Histogram of Ba ･･････････････････････････････････････････ 112

Fig. Ⅱ－２－８ Distribution map of Ba ････････････････････････････････････ 113

Fig. Ⅱ－２－９ Histogram of Cu ･･････････････････････････････････････････ 114

Fig. Ⅱ－２－１０ Distribution map of Cu ･･････････････････････････････････ 115

Fig. Ⅱ－２－１１ Histogram of Pb ････････････････････････････････････････ 116

Fig. Ⅱ－２－１２ Distribution map of Pb ･･････････････････････････････････ 117

Fig. Ⅱ－２－１３ Histogram of Zn ････････････････････････････････････････ 118

Fig. Ⅱ－２－１４ Distribution map of Zn ･･････････････････････････････････ 119

Fig. Ⅱ－２－１５ Histogram of S ･･････････････････････････････････････････ 120

Fig. Ⅱ－２－１６ Distribution map of S ････････････････････････････････････ 121

Fig. Ⅱ－２－１７ Distribution map of each element ･･･････････････････････ Appendix

Fig. Ⅱ－２－１８ Distribution map of principal factor 2 ･････････････････････ 122

Fig. Ⅱ－２－１９ Distribution map of geochemical anomaly zones ･･･････････ 123-124

Fig. Ⅱ－２－２０ Spectral chart ････････････････････････････････････････ Appendix

Fig. Ⅱ－２－２１ Result of spectral analysis ･･････････････････････････････ 125-126

Fig. Ⅱ－３－１ Location map of drilling survey ･････････････････････････････ 142

Fig. Ⅱ－３－２ Drilling site location of MJZC-1 ････････････････････････････ 143

Fig. Ⅱ－３－３ Drilling site location of MJZC-2 ････････････････････････････ 144

Fig. Ⅱ－３－４ Drilling site location of MJZC-3 ････････････････････････････ 145

Fig. Ⅱ－３－５ Geological columnar section(MJZC-1) ･･･････････････････････ 146

Fig. Ⅱ－３－６ Geological columnar section(MJZC-2) ･･･････････････････････ 150

Fig. Ⅱ－３－７ Geological columnar section(MJZC-3) ･･･････････････････････ 153

Fig. Ⅱ－３－８ Geological section of drilling survey ･････････････････････････ 157

List of Tables

Table Ⅱ－１－１ Result of microscopic observation ･･････････････････････････ 88

Table Ⅱ－１－２ Result of ore grade assay ･････････････････････････････････ 91

Table Ⅱ－１－３ Result of X-ray diffraction ･････････････････････････････････ 92

Table Ⅱ－１－４ Result of fluid inclusion test ･･･････････････････････････････ 95

Table Ⅱ－１－５ Result of isotope analysis(δ18O and δ13C) ･････････････････ 96

Table Ⅱ－１－６ Result of radiometric age determination(Ar-Ar method) ････ Appendix

Table Ⅱ－２－１ Result of chemical analysis for rock samples ･･････････････ Appendix

Table Ⅱ－２－２ List of statistic data for chemical analysis･･･････････････････ 127

Table Ⅱ－２－３ Correlation coefficient of minor elements ･･･････････････････ 128

Table Ⅱ－２－４ Result of principal factor analysis ･･････････････････････････ 129

Table Ⅱ－２－５ Result of spectral analysis･･･････････････････････････････ Appendix

Table Ⅱ－３－１ List of drilling equipment ･････････････････････････････････ 163

Table Ⅱ－３－２ List of used diamond bits and consumption goods････････････ 163

Table Ⅱ－３－３ Drilling summary ････････････････････････････････････････ 164

Table Ⅱ－３－４ Drilling schedule ････････････････････････････････････････ 167

Table Ⅱ－３－５ Result of laboratory tests for core samples ･･････････････････ 168

Table Ⅱ－３－６ Result of chemical analysis for core samples･･･････････････ Appendix

List of Plate

1. Geological map of Aurora and Rancho Viejo area (1:25,000)

2. Location map of rock and ore samples (1:25,000)

3. Location map of ore showings (1:25,000)

4. Distribution map of geochemical anomaly zones (1:25,000)

5. Result of spectral analysis (1:25,000)

6. Geological columnar section (1:200)

Part Ⅰ The General

Chapter 1 Introduction

1-1 The Background and Objective of the Survey

The Zacualpan area in the United Mexican Sates, target area for the survey, is of

high potential for the massive sulfide deposits containing polymetallic ore, similar type of

the Japanese Kuroko ore deposits. The Consejo de Recursos Minerales, (hereafter noted as

CRM) has aggressively conducted some exploration programs for the area in the past. The

Mexican government requested the Japanese government to survey for mineral resources

in the Zacualpan area.

The Japanese government responded to the request and decided to conduct an

exploration program to locate some potential zones for gold, silver, copper, lead and zinc

minerals of the massive sulfide and other types of ore deposits. The program was planed to

survey the geology and mineral occurrences in the field and to analyze those results.

1-2 Conclusions and Recommendation of the First Year

1 Conclusions

The regional geological survey, total survey line 500 kilometers and geological

description for the existing drilling cores, total logging length 4,000 meters, have been

performed in this year’s program.

The geological succession of the area is the Tejupilco Schist, Villa Ayala Formation,

Acapetlahuaya Formation and calcareous sedimentary rocks of the Teloloapan and

Pachivia Formations in the Guerrero terrene and the Morelos Formation of the Mixteco

terrene and overlain Cenozoic Balsas and Tilzapotla Rhyolite Formations and intrusive

rocks.

The Tejupilco Schist is mainly composed of weakly metamorphosed muddy to

sandy rocks accompanied with a small amount of green schist. The Villa Ayala Formation

consists mainly of basaltic to andesitic volcanic and pyroclastic rocks such as massive lava,

pillow lava, autobrecciated lava to pillow-breccia and hyaloclastite, and its upper part

contains alternation beds of a little salic andesite to dacite lava, tuff, slate, calcareous

sedimentary rocks. The Acapetlahuaya Formation is composed of mainly alternation beds

of well-bedded slate and sandstone and a small amount of calcareous sedimentary rocks.

The calcareous sedimentary rocks are mainly composed of black phyllite and foliated slate,

accompanied with sandy tuff or conglomerate and dark grayish muddy limestone, which

ranges from thin beds or lenses, several centimeters in thickness, to some large rock bodies,

1 to 2 kilometers in width in some places. The Morelos Formation consists mainly of

grayish black to grayish white massive limestone. It is stratified with thin beds of slate to

shale, or accompanied with thin beds and lenses of chert, 1 to 20 centimeters in thickness,

in some places. The Balsas Formation is mainly composed of reddish brown conglomerate.

The Tilzapotla Rhyolite Formation mainly consists of rhyolitic to dacitic pyroclastic rocks.

The intrusive rocks bodies are distributed in various sizes and the rocks are of rhyolite to

dacite and andesite.

The rocks of Guerrero terrene consisting of Tejupilco Schist, Villa Ayala and

Acapetlahuaya Formations and calcareous sedimentary rocks, has undergone the strong

deformation of folding and thrust faulting due to the Laramide orogeny. This kind of

deformation has not occurred in the Morelos Formation of the Mixteco terrene and

Cenozoic formations.

The mineralization in the area is of the massive sulfide ore and Tertiary vein-type

ore.

The massive sulfide deposits and mineral occurrences in the area are distributed

in the Aurora and Mamatla districts. That of the Mamatla district is in the footwall bed of

the ore horizon, seemingly in the pathway of rising hydrothermal solution. The ore horizon

is situated at the uppermost part of the green volcanic rocks of the Villa Ayala Formation.

It has been accordingly clarified that the ore horizon is of simultaneous deposition with the

alternation beds of a little acidic volcanic rocks and muddy to calcareous sedimentary

rocks.

Some vein-type ore deposits have been mined around Zacualpan, however only

two mines are in small-scale operation at present. Some vein-type mineral occurrences

have been seen in the existing drilling cores, however it is judged that the potential for high

grade and large-scale deposits is low in the area.

2 Recommendation for the Second Year’s Program

The distribution of the ore horizon and the geological environment of the massive

sulfide ore deposits have been revealed by the first year’s program. It is geologic

structurally assumed that the rocks of the ore horizon deposited in a specific environment,

however the details of these still remain unknown due to several times of strong

deformations by folding and thrust faulting. It is possible to assume that some kinds of

chemical elements (e.g.Pb, Zn, Ba, As, etc) have been concentrated in as geochemical halos

in the simultaneously deposited sedimentary rocks. Accordingly, it is possible to select

high-potential zones by more detailed geological and rock-geochemical surveys for the

alternation zones of the hanging wall volcanic and sedimentary rocks near the

mineralization centers.

Also it is possible to reveal the detailed geology by a drilling program of a few

hundred meters long within the hanging wall horizon and it will clarify especially the

details of the depth of the ore horizon, the state of the mineralization and alteration of the

footwall rocks. Furthermore, it will be able to perform a more reliable potential appraisal

for the area by an integrated analysis combined with results of the proposed surface survey

programs.

A geophysical (e.g. IP) survey program is useful to presume the sizes of the

potential targets afterward.

The following surveys are recommended in order of high priority.

1. Detailed geological and geochemical surveys in the hanging wall area.

2. Survey of structural drill holes in the hanging wall area (e.g. the Aurora district).

1-3 Outline of Phase Ⅱ

1 Survey Area

Aurora area and Rancho Viejo area are established by first year’s survey.

2 Survey Method and Contents

Second year’s program includes geological and geochemical surveys in Aurora area

and Rancho Viejo area, drilling survey in Aurora area and detail geological survey in

Santiago Salinas area. Contents and amount of the survey are listed in following table.

Contents and amount of the survey

Method and Contents Amount

Geological and Geochemical Surveys

Aurora Area

Survey area 65km2

Survey line 133.8km

Sample number（duplicate） 365(14)samples

Sampling density 5samples/km2

Rancho Viejo Area

Survey area 20km2

Survey line 41.3km

Sample number（duplicate） 81(7) samples

Sampling density 5 samples /km2

Santiago Salinas Area

Survey area 5 km2

Survey line 20km

Drilling Survey（Aurora Area）

Hole No. Depth Inclination Azimuth

MJZC-1 350m -90° －

MJZC-2 250m -90° －

MJZC-3 250m -90° －

Total 850m

List of Laboratory Tests

Contents Amount Geological Survey（Aurora area，Rancho Viejo area ） ①Thin section ②Polish section ③Ore assay ④X-ray diffraction ⑤Ar-Ar dating ⑥Fluid inclusion（with salinity） ⑦Isotope（ δ13C, δ18O on carbonate） ⑧Isotope（δ18O on silicate） ⑨Chemical analysis（REE+HFSE+LIL） （Ag,Ba,Ce,Co,Cr,Cs,Cu,Dy,Er,Eu,Ga,Gd,Hf,Ho,La,Lu,Mo,Nd,Ni,Pb, Pr,Rb.Sm,Sn,Sr,Ta,Tb,Th,Tl,Tm,U,V,W,Y,Yb,Zn,Zr)

45 45 15

100 3 15 6 30 45

Geochemical survey（Aurora area，Rancho Viejo area ） ①Rock chip Chemical analysis（Au+AASICP, 34 elements） （Ag,Al,As,B,Ba,Be,Bi,Ca,Cd,Co,Cr,Cu,Fe,Ga,Hg,K,La,Mg,Mn,Mo,Na, Ni,P,Pb,S,Sb,Sc,Sr,Ti,Tl,U,V,W,Zn,Au) ②Whole rock (major element, XRF) ③Spectral analysis

446

（duplicate21）

425 210

Drilling survey（MJZC-1, MJZC-2, MJZC-3） ①Thin section ②Polish section ③Ore assay ④X-ray diffraction ⑤Whole rock (major element, XRF) ⑥Fluid inclusion（with salinity） ⑦Isotope（ δ13C, δ18O on carbonate） ⑧Isotope（δ18O on silicate） ⑨Chemical analysis（REE+HFSE+LIL） （Ag,Ba,Ce,Co,Cr,Cs,Cu,Dy,Er,Eu,Ga,Gd,Hf,Ho,La,Lu,Mo,Nd,Ni,Pb, Pr,Rb.Sm,Sn,Sr,Ta,Tb,Th,Tl,Tm,U,V,W,Y,Yb,Zn,Zr)

15 15 15 15 15 3 3 3 3

3 Participant Member List of the Survey

Members participating in the field survey in Mexico are as follows.

Survey team

Japanese side

Shigehisa Fujiwara Head of survey team, Dowa Engineering co. ltd

Kazuyuki Ueda Dowa Engineering co. ltd

Hiroshi Jingu Dowa Engineering co. ltd

Mexican side

Ing. Gerardo Mercado Pineda CRM

Ing. Arturo Ruiz Ortiz CRM

Ing. Enrique Ontiveros Escobedo CRM

Ing. Carlos Bon Aguilar CRM

Supervisor in Mexico

Nobuaki Ishikawa Mineral Resources Survey Department, MMAJ

Masayoshi Itoh Representative of Mexico City office, MMAJ

4 Period of the Survey

Field survey was carried out as follows.

Whole term stayed in Mexico:

September, 16, 2002 ～ November, 26 , 2002

Field survey term:

September, 23, 2002 ～ November, 13 , 2002

Analysis and compilation of field data

November, 14 , 2002 ～ November, 20 , 2002

Drilling survey term:

October, 3 , 2002 ～ November, 15 , 2002

Chapter 2 Geography of Survey Area

2-1 Location and Access

The Zacualpan area is situated to the southwest of Mexico city, in Guerrero and

Mexico states. Principal villages in the survey area are Zacualpan, Ixcateopan Ixcapuzalco

and Teloloapan having population 16,000 is the largest village around the area, to the

south of the survey area. Base camps for the survey have been set at Teloloapan and

Zacualpan. The survey area is situated in the administrative districts of the above village

names.

Access to Teloloapan from Mexico City is possible in three hours by vehicles

through the highway via Iguala. To reach Zacualpan from Mexico city, it is possible to use

the highway through Toluca, taking the same hours. An outline of the access is shown as

follows.

200km 65km

Mexico city ------------ Iguala ------------- Teloloapan

2 hours 1 hour

A branch paved road from Highway No.51 connects Teloloapan and Ixcapuzalco.

Other paved roads from the northeast of the survey area to Zacualpan and from the east to

Ixcateopan are available. There exist other gravel roads connecting each village, but it will

become hard to use those roads in rainy season.

2-2 Topography, Climate and Vegetation

The survey area is geographically in the Sierra Madre del Sur (Raiz 1959) and

included in the Balsas-Mexcara sub-province near by the Neo-volcanic axis.

The northern area is in a high altitude area and shows many steep V-shape

valleys, but its altitude is getting lower toward south. The topography in the southern area

shows relatively gentle low land area. The Sultepec River in the west end of the area is 700

meters in lowest altitude and Cerro Tentacion to the south of Zacualpan is 2,710 meters,

highest in the area.

The drainage systems in the area are divided into three, separated by the

Cerro Tentacion. The Sultepec River system occupies about 60 percent of the whole survey

area and rivers running down to the southwest from the watershed have been formed in

the system area. The Los Sabinas River system occupies the southeast part of the survey

area and rivers running down to the south and southeast have been formed. The San Jose

River system occupies about 10 percent of the whole area at the northeast end and rivers

running down to the east have been formed. These systems constitute branches of the

Balsas River.

The climate in the area is of tropical to subtropical and its rainy season is from the

end of June to October, dry season from November to May. The average annual rainfall is

1,100 to 1,400 millimeters and the average temperature is 18℃ in Zacualpan.

The vegetation in the area is dominated by tall weeds in the lowland area, lower

than 1,800 meters in altitude. Some cornfields are partly seen there. In the highland area,

pine and oak trees grow scarcely.

2-3 Infrastructures

Electricity, communication and medical facilities are satisfactory available in

Teloloapan, one of our base campsite and two major bank offices are situated in the village.

Three gas service stations are located along Highway No.51. In the other villages in the

area, electricity and communication facilities are available, but no bank and gas station are

available. Satellite communication facilities are available in some small villages and

mobile telephones are useable along almost all roads and mountain or hill ridges.

The road networks are generally well developed, but almost all roads are not

paved and difficult to transit in the rainy season. It will be usual that all roads, except

major ones, blocked everywhere in July and August.

Chapter 3 Outline of Geology

3-1 Outline of Geology

Some regional geological survey programs have been conducted in the area by

some investigators such as Fries (1960), De Cserna (1965 and 1978) and Campa et al.,

(1974) and some geological frameworks for the region have been established. Campa et al.,

(1974, 1978 and 1979), specially, proposed a development history model of the geological

structure for an area named “Tierra Caliente” based on description of volcano-sedimentary

rocks of the Ixtapan de la Sal area. Coney and Campa (1987) and Sedlok et al., (1993)

proposed classifications of geological structure zones (Fig.Ⅰ-3-1) for the whole area of

Mexico respectively. The survey area of this report corresponds to the boundary between

the Guerrero Terrene and Mixteco Terrene, based on the classification by Coney and

Campa (1987).

De Cserna and Fries (1983), Guerrero et al., (1990, 1991 and 1993), and Elias and

Sanchez (1992) demonstrated a very detailed stratigraphic succession and a development

history of the geological structure for the volcano-sedimentary rock area. CRM has started

survey programs for massive sulfide ore deposits hosted in the volcano-sedimentary rocks

in the area, as a part of “Eje Neovolcanico” project in 1979 for the

Tlanilpa-Mamatla-Azulaquez area. Recently Valerie Gold Resources Ltd. was carried out

mineral exploration on Mamatla property in 1994-1998.

The survey area is situated in the Teloloapan terrene constituting part of the

Guerrero terrene and the Mixteco terrene in the eastern survey area, based on the regional

geological structure zone classification.

The stratigraphic succession in the Teloloapan terrene side is the Tejupilco

Schist, Villa de Ayala Formation (metavolcanic and sedimentary rocks), Acapetlahuaya

Formation, Amatepec Formation (simultaneous difference phase with Acapetlahuaya) and

overlying Teloloapan and Pachivia Formations, from the bottom. The Mixteco terrene is

consists of the Morelos and Mexcala Formations. These Formatios are unconformablly

covered by the Balsas Formation and Tilzapotla Formation of Tertiary age, Cuernavaca

Formation of Pliocene and alluvial sediments.

The Guerrero terrene has undergone the Laramide orogeny in early Tertiary time

(Salinas et al., 1994) and shows ductile deformation, isoclinal folding and thrust faulting

extending north to south. Generally it shows an east vergence. On the contrary, the

Mixteco terrene shows no ductile deformation, and it is said that the terrene has undergone

compaction stress from east to west.

A fault group trending northwest to southeast appears in this area after the

Laramide orogeny. It is possible that this fault group has been formed in a tension field

from northeast to southwest. Vein type ore deposits nearby Zacualpan are hosted in this

fault group.

3-2 History of Mining in the Area

A private company was aggressive for mining activity for the Azulaquez massive

sulfide deposit in the area from 1915 to 1920, and it is said that the Aurora, Capire, San

Francisco, Guadalupe, Cruz Blanca and San Antonio deposits were developed at that time

(Ochoa et al., 1985). These mines were closed because of deletion of ore reserves.

Peñoles Company conducted a geophysical and drilling program in this district in

1975, but they withdrew from the Azulaquez district.

La Campana Company operated the Rey de Plata mine, about 10 kilometers

southwest of Teloloapan, applying open-pit and underground mining methods from 1946 to

1949. The main target was silver. Afterward, Peñoles conducted a drilling and

underground adit exploration program from 1975 to 1991 and confirmed around 2,000,000

tons of massive sulfide ore reserve after 24,000 meters drilling. Recently Industria Peñoles

S.A. de C.V. Dowa Mining Co., Ltd. and Sumitomo Corporation started operation of Ray de

Plata mine in October 2,000 at a rate of 3,000tones per month. But it was suspended

because of low price of Zn in December 2001.

In Zacualpan, many vein type ore deposits of silver, lead and zinc have been

developed since the Spanish colony time, however only the Cuchara and La Alacrán mines

are in 350 tons a day operation by El Provenir de Zacualpan S.A. de C.V. at present.

Chapter 4 Integrated Discussion of Survey Result

FigureⅠ－4－1 and FigureⅠ－4－2 show the integrated interpretation map

and geological model of Aurora area respectively.

4-1 Characteristics of Mineralization and Geological Structure

・Geological Structure

Zacualpan area is included in Guerrero terrain as the province of geological

structure. There are some characteristics in the formation that consists of Guerrero

terrain. One is that the formation has undergone the regional deformation as a result

of Laramide orogeny in early Tertiary. Another characteristic is that it is accompanied

with massive sulfide ore deposits such as the Tizapa, the Rey de Plata and other ore

deposits.

The geology of the Aurora and the Rancho Viejo areas are mainly composed of

the rocks of the late Jurassic to the middle Cretaceous. The area consists of Villa Ayala

Formation that is composed of volcanic rocks partly includes sedimentary rocks and

the Pachivia Formation of calcareous sedimentary rocks and volcanic rocks that

conformably overlain the former Formation.

The Villa Ayala Formation mainly consists of andesitic volcanic rocks. In the

Aurora area, it includes large quantities of dacitic volcanic rocks and sedimentary

rocks. The existent Capire and Aurora deposits occur within the sedimentary rocks

formed in the late stage of volcanic activity of the Villa Ayala Formation. After the

formation of ore deposits, the regional deformation occurred and the geology around

the area is markedly formed in block by developed overturned folding, thrust and fault

structure in the EW and NW directions.

・Mineralization

The existent massive sulfide ore deposits in Aurora area are mainly lenticular

ore bodies with lack of continuity. They are hosted in the alternation of slate, limestone

and tuff. The common characteristics of the minerals of these ore deposits are rich in

Au, Ag, Pb and Zn, and are accompanied with comparatively much quantity of sulfate

minerals (gypsum, baraite). By the past drilling survey, comparatively high grade

parts of Ag, Pb and Zn were intermittently intersected in the shallow part of the

sedimentary rocks between the Capire and the Aurora deposits. On the other hand, in

the drilling hole (TN-14) that is 1.5 km north from the Capire deposit, the massive ore

body that is mainly composed of pyrite was intersected in the boundary part between

the sedimentary rocks and the pyroclastic rocks of its footwall.

In this survey, the indications of massive sulfide type mineralization as same

as in TN-14 were found in the shallow part of MJZC-1 and in the several parts of the

surface around Tlanilpa and Santiago Salinas.

・Alteration

Around the existent massive sulfide ore deposit, strong sericitization and

pyrite dissemination is partly observed. However, the scale of alteration zone is small

with lack of continuity. In the existent drilling hole near the Capire deposits, though

the alteration of footwall andesite overlaid the sedimentary rocks, is chlorite-sericite

alteration and pyrite dissemination, the structure of the original rocks is preserved.

On the other hand, the alteration of the volcanic rocks of the footwall is marked and

the network of sulfide is developed in drilling hole TN-14. Therefore, TN-14 is

considered to be closer to the center of the hydrothermal activity. In the places of ore

showing around Santiago Salinas, sericite and pyrite dissemination zone is

intermittently observed within footwall dacite. Moreover, alteration minerals such as

kaolinite and gypsum that is accompanied by above ore showing are observed.

Consequently, hydrothermal activity is considered to have been active around Santiago

Salinas.

・Genetic Condition

The sedimentary rocks that hosted the existent ore deposit are often

accompanied with the mudball like rock fragments. The sediments of the same horizon

that is confirmed in MJZC-3 core indicate that they were not formed in geologically

calm environment or probably formed by resedimentation. For example, fragments of

tuff are often included within the slate and fragments like mudball are included within

tuff. As mentioned in previous clause, since the alteration of the footwall is weak in

the existent ore deposits, following probability are considered. The ore deposits are

formed in distal place from the center of mineralization by the property of the

sedimentary rock embedded ore body. Or they are considered to be formed by

resedimentation of ore body with the sedimentary rocks with high probability.

・Vein Type Mineralization

There are metalliferous vein type ore deposits in the northern part of the

Aurora area. The main components of the ore are Ag, Pb and Zn as same as massive

sulfide type. The difference of metalliferous vein ore between the massive sulfide ore is

poor in Ba and accompanied with As minerals. The homogenization temperature of

fluid inclusions in each ore deposit is considered to have been consisted of a single

population and not to have been affected by late hydrothermal solution and

metamorphism. Therefore, the metalliferous veins with the NW direction were formed

by the hydrothermal activity that was the same origin of veins of Zacualpan in Tertiary.

The mining target of and around the existent ore deposits is considered to have been

the high Ag grade part, because the analysis result of 2,700g/ton for Ag in waste of the

San Carlos deposit was reported (CRM). Many ores show hydrothermal brecciated

structure and are accompanied with quartz and amethyst as gangue.

・Comparison to the ore deposits in neighboring region

Guerrero terrain, including the Zacualpan area, includes many indicates of

massive sulfide ore deposits that resembles to kuroko deposit such as the Tizapa and

the Rey de Plata ore deposit and also ore showings like the Aurora area. These ore

deposits and the ore showings were formed in the last stage of andesitic submarine

volcanic activity, and commonly occur covered or accompanied by muddy sediments.

The grades of ores are similar and mainly composed by Au, Ag, Pb and Zn. The

different point is that the ores of the Rey de Plata ore deposit and the Aurora area

contain much sulfate minerals (gypsum, barite). On the other hand, the ores of the

Tizapa less contain these minerals.

The occurrence of the ore bodies vary depends on the areas. The main ore

deposit in the Tizapa occurs between greenschist and graphitic phyllite, on the other

hand, in the Rey de Plata it occurs among green volcanic rocks with thin sedimentary

rock layers. The Aurora deposit occurs within the alternation of sedimentary rocks.

The common point, however, all the three deposits are complicatedly folded by the

cause of regional metamorphism.

Though the alteration of the footwall is not markedly developed like the

Hokuroku area of Japan, it is generally accompanied by distinct sericitization and

pyrite dissemination.

The estimated ore reserves of the Tizapa are 10 mt and the Rey de Plata is 2.0

mt. The ore reserve of the Tizapa in which the hanging wall of mudstone bed is

developed well, is bigger than that of the Rey de Plata.

The progress of the survey is as follows: At first, the exposed lenticular ore body was

observed in slate of the hanging wall side in the Tizapa ore deposit. Then the existence

of the ore body was mainly confirmed by drilling survey around the exposed ore body.

In the Rey de Plata ore deposit, prospecting was carried out firstly around the outcrop

of alteration zone that was accompanied by high grade Ag. After that the massive ore

body was found through expanding the survey area by drilling survey. In the Aurora

area, since the lenticular ore body was already confirmed, the progress of prospecting

is expected by almost same process in the Tizapa ore deposit.

4-2 Mineralization and the Result of Geochemical Survey

The anomaly area of each rock facies that is shown by alteration index (more

than +1σ of average) obtained from bulk rock chemical analysis of major elements are

widely distributed from the Capire to the Cruz Blanca deposit around the existent ore

showings in the Aurora area. Although the distribution of the alteration zone of the

marked outcrop is limited, the area that is shown by alteration index is wide. The area

can be considered as the halo of the mineralization. The other anomaly zones are

sporadic, however, it reflects the alteration in some degree except the samples from the

ridge that is provably reflect the weathering.

The anomaly zone of alteration index distribute in the direction from the

south to the north is observed in a part of the northwestern Rancho Viejo area.

Same trace elements behavior well reflects the metalliferous vein type

mineralization. That is, the plus anomalies of As, Zn, Pb and Cd are marked and Ba

shows minus anomaly. Regards the mineralization of massive sulfide mineral, As and

S forms comparatively wide halo. As regards the other elements, Au, Ag, Ba, Pb and Sb

are possible to reflect the alteration related to the mineralization in the limited

condition. The elements other than the above elements may reflect the original rock

facies or it is difficult to estimate the mineralization process since most of them cannot

to be detected.

Principal component analysis was carried out in order to make general

evaluation of the mineralization. The geochemical anomaly of the second principal

component (high load of As, Pb, Ag, Au, S, Sb, Mo) that is considered to reflect the

mineralization was extracted in the vicinity of the La Campana, the southern Velixtla,

the Santiago Salinas and the Capire to the Aurora II deposits, respectively.

4-3 Potential for Ore Deposit

The massive sulfide type ore deposits of Guerrero terrain occur in the upper

part of green volcanic rocks. They are commonly covered with sedimentary rocks. This

survey revealed that the distribution of the sedimentary rocks that is considered as the

hanging wall of the ore deposits in the Aurora area.

Considering the distribution zone of hanging wall, ore showings, alteration

zone and geochemical anomaly zones, the south part of Santiago Salinas, surrounding

of La Campana and north of Capire are prospective districts for massive sulfide

mineralization in the area. Moreover, prospecting has not performed yet in those areas.

For the surrounding of La Campana, in other words, there is thick hanging

wall alternation of slate and tuff, accompanied by altered rock fragment, and

geochemical anomalies are concentrated there. The alteration with pyrite

dissemination is recognized in schistose volcanic rocks of the footwall.

In the Santiago Salinas, the network of mineralization is observed within

footwall dacite overlaid sedimentary rock, where Ba contents shows approximate 1

percent and is accompanied with geochemical anomaly and alteration with sericite,

gypsum and kaolinite. Therefore, if the mineralization of Pb, Zn and other sulfide

minerals becomes predominant toward the south, the possibility of existence of

massive sulfide type ore deposit becomes higher.

By observing the marked geochemical anomaly, the north of Capire is

considered to be close to the center of mineralization. This area is considered to be

worth to carry out the prospecting. Particularly, the layered pyrite ore body that was

intersected by drilling hole (TN-14) in the vicinity of the mineralization indicate area

of Tlanilpa is expected to be converted to kuroko type deposit toward the east that

the sedimentary rocks of the hanging wall becomes thicker.

ZN:133ZN:133ppmppm, Ba:1.01%, Ba:1.01%ZN:133ppm, Ba:1.01%

ZN:337ZN:337ppmppm, Ba:401, Ba:401ppmppmZN:337ppm, Ba:401ppm

Pb:0.20%, Zn:4.82%, Ba:34Pb:0.20%, Zn:4.82%, Ba:34ppmppmPb:0.20%, Zn:4.82%, Ba:34ppm

Zn:71Zn:71ppmppm, Ba:467, Ba:467ppmppmZn:71ppm, Ba:467ppm

35

70

80

60

85

Sedimentary Rocks(Us, Ms, Ust, CFm, CFv)

Alteration Index (>M+1 )

S (>M+1 )

PC2 (<M 1 )

Chapter 5 Conclusions and Recommendation

5-1 Conclusions

Following surveys are carried out in second year: The geological and

geochemical survey in the Aurora area and the Rancho Viejo area, the detail geological

survey in the Santiago Salinas area and three drilling survey in the Aurora area.

The geology of the Aurora area is composed of the Villa Ayala Formation, the

Pachivia Formation and intrusive rocks.

The Villa Ayala Formation is composed of schistose volcanic rocks (Lsh),

schistose sedimentary rocks (Lss), andesites (Va1～Va6, Vam), dacite (DCw, DCe, DCn,

DCc, Vad) and sedimentary rocks (Us, Ust, Ms).

The Pachivia Formation consists of the layers (CFm) that are mainly

composed of slate and volcanic rocks (CFv).

The geological structure is complicatedly controlled by the folding and fault

structures whose axis is NNE to NNW with the gently inclined cleavage. As a whole,

andesite Va-1 is located in the central part and sedimentary rocks surround it, the

outsides of the sedimentary rocks andesites Va-2～Va-5 are distributed. Dacite rock

bodies are distributed in the south west and south east of the area and schistose

volcanic rocks and sedimentary rocks occupy in the corner of the northwestern part of

the area. The Pachivia Formation is distributed in a belt with the direction of north

to the south in the eastern part of the area. The Formation dips westward in

appearance, but the horizon is judged to be overturned by the fossil age and the folding

pattern.

There are massive sulfide type ore deposit and metalliferous vein type ore

deposit as the mineralization of the Aurora area. Within the above massive sulfide ore

deposit, the Capire, the Aurora and the Manto Rico ore deposit occur within the

sedimentary rocks of the upper part of the Villa Ayala Formation. On the other hand,

the Guadalupe and the Cruz Blanca deposit occur within the uppermost part of the

Pachivia Formation. These ore deposits are relatively rich in Pb, Zn, Ag and Ba. As a

result of this year’s survey, the Santiago Salinas district and the La Campana district

were found as the place of ore showing. The detail geological survey was carried out in

the Santiago Salinas district and confirmed the horizon of occurrence of massive

sulfide ore deposit.

Based on the geochemical survey, the zone that shows more than +1σ of

average alteration index of each rock facies is considered to reflect the halo of the

alteration related to the massive sulfide alteration. It became obvious that there are

high possibility of that Ag, As, Zn, Pb, Cd and Ba as the trace elements to the

indication elements for metalliferous vein type and Au, Ag, As and S as the indication

elements for massive sulfide type ore deposit are effective. Besides the above, principal

component analysis can extract the anomaly related to the mineralization in the La

Campana, the south of Velixtla, the Santiago Salinas and around the Capire to the

Aurora deposits.

The horizon of massive sulfide ore deposit was observed in the shallow part of

the drilling hole MJZC-1. Sulfide network was also observed within the footwall dacite.

This horizon continues to the place of mineralization indicate of Tlanilpa and the

drilling hole TN-14 that was already drilled. Drilling hole MJZC-2 intersected volcanic

rocks that develop schistosity. Though the volcanic rocks show strong pyrite

dissemination, the horizon of these volcanic rocks were judged to be lower than the

horizon of massive sulfide ore deposit. Drilling hole MJZC-3 intersected the

sedimentary rock that is the same as the host rocks of the Capire and the Aurora

deposit were observed in the depth of 149.5 meters. The weak pyrite dissemination and

mineralized rock fragments were sampled in the same depth. Under the sedimentary

rock, andesite lava of the Villa Ayala Formation that corresponds to andsite Va-4 of the

surface was observed.

The geology of the Rancho Viejo area is composed of the Villa Ayala Formation,

the Pachivia Formation.

The Villa Ayala Formation is composed of basalt to andesitic rocks (Va) and

dacite (Vd). The quantity of the dacite is less than that in the Aurora area.

The Pachivia Formation is composed of basalt to andesitic tuff (CFv),

limestone (CFL), slate (CFs), and alternation of tuff and slate (CFt).

As the geological structure, cleavage with the direction of NNE～NNW

develops as same as in the Aurora area, it shows that the folding structure in the NNE

～NNW direction is dominant. The dip of the strata is west in appearance and the

strata is generally overturned.

Though alteration accompanied with mineralization is observed in several

places, all of them were small scale and the zones were limited.

Geochemical anomaly zones of alteration index are outlined in part of the

northwestern district of the Rancho Viejo area by geochemical survey.

Considering the above facts, the north of Capire district, the Santiago Salinas

district and La Campana district in the Aurora area, are considered to be the

prospective zones for ore deposit (shown in figure 1-5-1), since those districts have

thick distribution of hanging wall, geochemical anomaly and remarkable ore showing.

Although the distribution of the horizon of massive sulfide ore deposit and the

hanging wall were developed in Rancho Viejo area, ore showing and marked

geochemical anomaly are rarely observed. Consequently, the potential for ore deposit is

considered to be small in the Rancho Viejo area.

5-2 Recommendation for the Third Year’s Program

The distribution of sedimentary rocks related with massive sulfide deposits

(Capire deposit, Aurora deposit, etc.), ore showings, alteration zone and these

relationships have been revealed by the second year’s program. Distribution pattern of

specific elements that indicate mineralization and geochemical characteristics in the

surveyed area was outlined by geochemical survey.

The previous exploration data that was obtained in this survey, showed the

existence of unexplored districts such as Santiago Salinas, La Campana and north of

Capire deposit districts.

Massive sulfide type mineralization is expected in Santiago Salinas district

where is underlain by hanging wall sediments and alteration occurred in footwall

dacite accompanying mineralization (Ba:1%).

There is little previous exploration in La Campana district located in the west

of Manto Rico deposit, due to private mining concession. But, this survey has defined

geochemical anomaly, ore showings and ore horizon in the district. Moreover, Drilling

hole MJZC-2 encountered footwall alteration and mineralization which are correspond

to the exposure in the creek situated to the west of Otates. Therefore, Massive sulfide

ore body is expected in the depth of 200-300m below the surface between Manto Rico

deposit and La Campana.

Exploration program must be advanced in north of Capire deposit district

where exhibits geochemical anomaly and alteration zone, and is expected the

continuation of mineralization intersected hole TN-14. Since the previous drilling did

not confirm the ore horizon below thick sedimentary rocks, the deep drilling program is

desirable.

As mentioned above, farther investigations must be recommended in the

followings prospective districts to confirm continuation of mineralization and ore

horizon.

1. Santiago Salinas district

2. La Campana district

3. North of Capire deposit district

ZN:133ZN:133ppmppm, Ba:1.01%, Ba:1.01%ZN:133ppm, Ba:1.01%

ZN:337ZN:337ppmppm, Ba:401, Ba:401ppmppmZN:337ppm, Ba:401ppm

Pb:0.20%, Zn:4.82%, Ba:34Pb:0.20%, Zn:4.82%, Ba:34ppmppmPb:0.20%, Zn:4.82%, Ba:34ppm

Zn:71Zn:71ppmppm, Ba:467, Ba:467ppmppmZn:71ppm, Ba:467ppm

35

70

80

60

85

Sedimentary Rocks(Us, Ms, Ust, CFm, CFv)

La Campana area

Capire area

Santiago salinas area

Alteration Index (>M+1 )

S (>M+1 )

PC2 (<M 1 )

Pert II Detailed Discussion

Chapter 1 Geological Survey

1-1 Survey Method

The survey route lines have been set up in the Aurora and Lancho Viejo areas

after study of existing geological data. The topographic maps scaled 1:10,000 enlarged

from existing maps scaled 1: 50,000 have been used for the route mapping, and GPS

has been utilized for confirmation of position.

The principal subject of the survey is to make clear its geological classification,

geological structure, and the state of alteration and mineralization. The mineralized

zones and outcrops have been surveyed by a simple method, and specific important

outcrops have been sketched 1:100 to 1:200 in scale and recorded in photographs. The

survey results have been summarized in a geological map scaled 1:25,000. The

proposed detail survey district, Santiago Salinas, has been summarizes in a rout map

scaled 1:10,000 and geological map.

The specimens of all typical rock types and facies, mineralized occurrences,

and alteration zones have been taken to make clear their mutual relations. Microscopic

observation of rock thin sections and polished ore samples, powder X-ray diffraction

analysis, fluid inclusion analysis, isotopic analysis, age dating, and chemical analysis

for rocks and ore minerals have been conducted to integrate with the geological survey

results.

1-2 Survey result

1 Aurora Area

Aurora Area is situated near by the center of the Zacualpan area and is

divided by a watershed running north to south in the center of the district. The

western part belongs to the Sultepec River system, and the principal part is in the

Paso del Carizo River and its branches. The altitude of the east end of the district is

1,050 meters along the Paso del Carizo River. The area from Otates to the south shows

gentle topography, but other areas are in rugged terrain. The maximum relative height

from the river level is 500 meters in the northern district.

The eastern part belongs to the Los Sabinas River system. The topography of

the part is generally rugged, and its altitude increases to the northeast, reaching to

2,200 meters in Tecolote, the northeast end of the district.

The principal villages are Otates, Pericones, Tlanilpa, Santiago Salinas,

Aurora, and Azulaquez, but they are all small municipalities.

(1) Geology

Figures II-1-1 to II-1-5 show schematic columnar section, geological map,

cross section, location map of samples, and location map of mineral occurrences. The

Aurora area is underlain by the Villa Ayala Formation, Pachivia Formation, and

intrusive rocks.

(i) Villa Ayala Formation

The formation is composed of schistose volcanic rocks (Lsh), sedimentary

rocks (Lss), andesitic rocks (Va-1 to Va-6, Vam), dacitic rocks (DCw, DCe, DCn, DCc,

Vad), sedimentary rocks (Us, Ust, Ms), and intrusive rocks (Dio)

(a) Schistose Volcanic Rocks (Lsh)

The rocks are distributed in the northwestern end of the district, northwest of

Otates. Schistosity and foliaton planes are well developed in the rocks. Green schist

rich in chlorite and quartz-sericitic schist rich in sericite appear alternatively. The

sericitic schist sometimes gradually changes from green schist, being accompanied by

pyrite, and some of them are formed by alteration from green schist. It is possible that

some green schist rocks are originated from andesitic rocks due to presence of vitric

materials and plagioclase relics. Under the microscope, some epidote and chlorite are

seen as principal minerals being accompanied by calcite and opaque minerals.

They gradually change from schistose sedimentary rocks (Lss) with

alternation zones in their boundary.

(b) Schistose Sedimentary Rocks (Lss)

The rocks distributed from around Otates in the northwestern district to the

junction of the Paso del Carizo River and El Manto Stream to the south-southeast.

They are composed of alternations of black slate, quartzose sandstone, and tuff, several

tens centimeters to several meters in thickness. They apparently contain large

amounts of sericite or muscovite, and show some crenulation folding. They are in some

places being accompanied by thin layers containing large amounts of hematite, several

millimeters in thickness. Under the microscope, sandstone contains large amounts of

quartz grains, and small amounts of feldspar fragments and calcite with less amount

of groundmass.

(c) Andesitic Rocks (Va-1to Va-6, Vam)

The rocks are distributed in the central district as several separated bodies.

・Va-1 is distributed around El Copal as a mass extending northwest to southeast. The

rock facies is of green to grayish green and yellowish-grayish green pyroxene andesite.

They are composed of massive lava, autobrecciated lava, lapilli tuff to hyaloclastite,

and breccia. Schistosity is seen in some edges of the body, but the rocks are generally

massive, and well preserve the source original texture. The bodies situated to the west

of the Tlanilpa and Capire deposits tend to be enriched by plagioclase phenocrysts,

grading to dacitic rocks. Under the microscope, they are mainly composed of chlorite

and calcite, being accompanied by small amounts of epidote and opaque minerals, and

to be judged propylite. Rocks showing porphyritic texture are olivine-bearing pyroxene

andesitic.

・Va-2 is distributed in an area to the north of the Manto Rico deposit in the northern

district. The rocks mainly consist of tuffs enriched in green vitric material,

autobrecciated lava showing porphyritic texture and lapilli tuff to tuff breccia. The

tuffs show relatively well developing schistosity and foliaton. The rocks in the upper

stream of the El Manto River contain black mad balls, several meters in diameter.

Under the microscope, the rocks are judged altered rocks mainly consisting of chlorite,

calcite, and opaque minerals being accompanied by plagioclase and epidote.

・Va-3 is distributed in an area from San Carlos to the Yerba Buena deposit, and the

ridge area conforming watershed in the central northern district, The rocks are mainly

composed of schistose tuff and porphyritic pyroxene andesite lava, but they form

alternation of andesitic to dacitic lapilli tuff and tuff breccia. The tuff presents in two

different types, one containing green vitric fragments and another rich in coarse

plagioclase fragments. Under the microscope, the tuff shows clear cleavage texture,

mainly consisting of some altered minerals such as quartz, chlorite, sericite, and

calcite, being accompanied by plagioclase relics and small amounts of epidote and

opaque minerals.

・Va-4 is distributed in the central southern district, in a zone from the Capire deposit

to Metlixtapa. The rocks are grayish green containing small to medium amounts of

plagioclase phenocrysts, and show slightly unclear autobrecciated texture. Schistosity

is weak. Under the microscope, augite and plagioclase are seen. Some metamorphic

and altered minerals such as chlorite, calcite, and small amounts of epidote and

opaque minerals are seen.

・Vam is distributed in the middle stream area to the southeast of Santiago Salinas in a

belt zone, apparently below Va-4. They are grayish to greenish gray silty tuff, being

accompanied by mud balls and several layers of thin muddy beds, several tens meters

in thickness, and mud balls.

・Va-5 is distributed as a layer in a dacite body. The rock distributed along the Paso del

Carrizo River shows autobrecciated texture, being accompanied by thin layers of

mudstone and tuff. Others are of tuff containing green vitric fragments, and show

schistosity.

・Va-6 is distributed as thin layers in dacite bodies in the northeastern and southern

districts. The rocks are fine-grained schistose green tuff.

(d) Dacitic Rocks (DCw, DCe, DCn, DCc)

The rocks are distributed in the southeastern and southwestern districts as

relatively large-scale bodies, and in the northwestern and central districts as

small-scale bodies.

・DCw is distributed in the southwestern district, showing gray to greenish gray, and

being accompanied by several percent of plagioclase phenocrysts. Schistosity tends to

obvious to the north. In the southern part, the rocks show elongated lenticular texture,

10 to 30 centimeters in diameter, in some places. The rocks around andesite Va-5 to the

northwest of Santiago Salinas show black vitric parts in some places and aqueous

autobrecciated texture.

・DCe is distributed in the southeastern district. The rocks show grayish green, being

rich in vitric material in many cases. They are mostly pyroclastic rocks contain several

percent of plagioclase phenocrysts, and mainly consist of small amounts of accidental

rock fragments such as andesite and silicified altered rocks. The rocks alternate with

sedimentary rocks in the rim of rock bodies, and contain mud balls of slate in Cruz

Blanca. Under the microscopic observation of specimens taken in the northeast of

Metlixtapa, porphyritic quartz, calcite, and plagioclase phenocrysts altered to sericite

are seen in the altered fine-grained vitric groundmass.

・DCn is distributed from the Manto Rico deposit to La Campana in the northwestern

district. The rocks are grayish green, schistose, and vitric, containing plagioclase

phenocrysts. The lower parts are graded to alternation with slate.

・DCc is distributed from Velixtla in the northern district to the Capire deposit in the

central, consisting three layers. The rocks are vitric lava to tuff rich in plagioclase

phenocrysts, showing some schistosity. They show grayish white in weathered parts,

but grayish green in fresh parts. They are accompanied by thin layers of andesite and

muddy rocks in the lower part to the south of Velixtla.

・Vad is mainly composed of dacite as well as DCw, being accompanied by andesite thin

layers. Under the microscope, the intercalated andesite is judged altered andesite

containing plagioclase phenocrysts and small amounts of augite, being seen chlorite,

epidote, and opaque minerals.

(e) Sedimentary Rocks (Us, Ust, Ms)

The rocks are composed of alternations of slate, limestone, tuff, and breccia.

Us is named for those distributed in the central district, Ust in the northwestern

district, and Ms in the southern district.

・Us is the host unit for the Aurora I and II deposits, and Capire deposit. The rocks are

mainly composed of layered gray limestone and black slate, being accompanied by

vitric tuff and lapilli tuff. Schistosity and small folding structure are significant in the

rocks, and tuff containing some mud balls; siliceous rock (chart?) lenses are seen

around the ore deposits. Schistosity is seen in the limestone, and some recrystallized

fossil bearing beds are seen near by MJZC-1 drill hole.

・Ust is of alternation zones of slate and tuff. The slate is tuffaceous, changing its color

to gray due to weathering in some places. The La Campana Occurrence is in Ust.

・Ms consists of alternations of slate and limestone, being accompanied by tabular

layers of mineralized siliceous breccia in lapilli size, 10 to 30 centimeters in thickness.

Cleavage is well developed in the rocks, and some folding structure is significant.

Several mineral occurrences are in DCw covered by Ms.

(ii) Pachivia Formation

The calcareous sedimentary rocks distributed in the eastern Aurora area are

correlated to the Pachivia Formation in the Cuernavaca Quadrangle due to their

continuity. The rocks in the district are composed of layers of slate (CFm) and volcanic

rocks (CFv).

・CFm is distributed in the eastern district extending north to south. Also they are in

Velixtla in the northern end and in C. Pena Colorada in the southern end, covering

mountain tops in small areas. They are composed of well-foliated black slate, limestone

layers mainly consisting of calcareous slate, and andesitic tuff. The limestone strata

are variable in the thickness, and poor in continuity. They show a kink folding

structure, boudinage of thin limeston layers, and recrystallized fossil rich layers.

・CFv is distributed around Azulaquez extending north to south. They are generally

dark green to grayish green autobrecciated andesite to basalt and breccia contain

fragments of andesite to basalt, dacite and slate. The rock facies of the autobrecciated

lava is of pyroxene andesite, and basaltic rock rich in gas cavity and poor in

phenocrysts. Under the microscope, the autobrecciated rocks around Azulaquez are

andesite containing augite and hornblende phenocrysts, and calcitization and

chloritization of the rocks are slightly strong.

(iii) Intrusive Rock (Dia)

The rocks are distributed in a stream to the northwest of the Yerba Buena

deposit. The rocks are dark green andesite or micro-diorite. A small outcrop is exposed

in a mountain road near the Aurora deposit, but its relation with surrounding rocks is

unknown. It is supposed to be intrusive rock, because no schistosity is seen in the rocks.

Under the microscope, it is judged pyroxene andesite, and most of pyroxene crystals

have undergone alteration, only remaining their pseudomorph. They are accompanied

by small amounts of pyrite in many cases.

(2) Structural Geology

Significant foliation has been developed in the rocks of the Aurora area. It is

supposed that this is due to the Laramide Orogeny of the early Tertiary (Salinas, 1994

etc.), and this extends all over the Guerrero terrene.

The foliation planes are extensive as penetrative cleavages in the fine-grained

tuff, and their principal folding structures are parallel to the penetrative cleavages

plane. From the field observation of the rock facies distribution, penetrative cleavage,

bedding plane, and folding structure, it is thought that there exist a southwesterly

inclined overturned anticline structure to the southeast of Santiago Salinas and a pair

of overturned anticline and syncline structures to the southeast of the drill hole

MJZC-3.

The tendency of structure has been investigated through a stereo projection of

the penetrative cleavages and bedding planes (Figure II-1-8).

The most of cleavages in the schistose volcanic rocks (Lsh) and sedimentary

rocks (Lss) in the northwestern district show of low angle and dispersion. The bedding

planes tend to incline to the east-northeast, but are dispersed as well as the cleavage.

It is supposed that this probably reflect undulation due to the late stage bending fold.

Although a few measurement data are available in the area from the Manto

Rico deposit to Velixtla, but the cleavages strike east-northeast and dip to the

northwest, and concentrate to low angle. The strike tends to change to the east to west,

to the west-northwest. The bedding planes have same tendency as that of the

cleavages, and generally reflect the bending fold having axis of northwest.

In Santiago Salinas, the cleavages tend to concentrate to the northwest strike

and southwest dip, based on few measurement data. The bedding planes tend to

concentrate to the northwest strike and the southwest gentle dip, and the east to west

strike and the north dip. It is thought that there exists isoclinal holding showing the

northwest trending axis.

The penetrative cleavages of the volcanic rocks (Va-3, Dce, DCn) in the

northeastern and southeastern districts gently dip to west, and its strike shifts from

the north-northwest system to the north to south system, and to the east-northeast to

system. The bedding planes and cleavages of the sedimentary rocks (Us) tend to show

the northeast strike and the west dip. It is supposed that this area has undergone

affect of the northwest extending bending fold.

The Pachivia Formation in the eastern district shows same tendency as that

of above-mentioned volcanic rocks, possibly being affected by the northwest extending

bending fold.

(3) Mineralization and Alteration

The massive sulphide type and vein type mineralization and alteration are

recognized in this district.

(i) Massive Sulfide Type

There exist the Manto Rico, Capire, Aurora I&II, Guadalupe (Salitre Grande),

and Cruz Blanca as the massive sulphide type deposits, and the Tlanilpa as mineral

occurrence. In the Santiago Salinas area, several massive sulphide type mineral

occurrences and alteration zones have been confirmed in this survey.

(a) Manto Rico Deposit

The deposit is situated in the upper stream area of the El Manto Stream in

the northwestern district. Two adits can bee seen both sides of the stream, but it is

supposed that the left bank zone would be its active area in the past because of

existence of some waste dump mounds. An adit orienting N15°E is recognized, even it

has been buried at present, and a layered mineralized zone of pyrite is found in an

outcrop. The host rock is of an alternation of slate and fine-grained tuff. No significant

alteration zone exists.

The geological structure there shows generally inclines to the north. From

lower to upper, cherty lenses, tuff containing some mud balls, dacite (DCn), and

andesitic tuff (Va-2) lie on the upper part. Some cleavages gently inclining to the west

are seen there, and the strata have been bended. In the down stream area, a slate

dominant zone contains some pyrite thin layers.

The sample taken from an outcrop of the mineral occurrence contains only

pyrite grains, but some sample from the waste dump shows 500 ppm Ag and 53.1 % Ba

in the assay result, indicating to be barite ore. The ore constitute minerals are

sphalerite, tetrahedrite, and small amounts of galena, pyrite, and chalcopyrite.

(b) Capire Deposit

The Capire and Aurora (I) deposits are near the mountain ridge in the central

district, the former on the western side and the latter on the eastern side, about 500

meters apart. In the Capire deposit, a buried shaft and small-scale adits exist along

east to west extending ridge. It is thought that the host rocks of the mineral are an

alternation of calcareous slate and tuff containing mud-balls. The footwall is of the

dacite rich in plagioclase phenocrysts (DCc) and andesitic lava (Va-1). Weak pyrite

dissemination is seen in the tuff, but its alteration zone is small-scale. The assay result

of a black ore-type waste rock sample shows 1,900 ppm Ag, 36.7 % Ba, 12.7 % Zn, and

5.09 % Pb. Large amounts of sphalerite and medium amounts of tetrahedrite, galena,

and pyrite have been confirmed in their polished sections. Framboidal and colloform

texture are seen in the pyrite ore.

(c) Aurora (I) Deposit

A submerged inclined shaft exists nearby a junction of streams in the mine

area. An apparent hanging wall andesite partly contains strong dissemination and

films of euhedral pyrite. Large amounts of sphalerite, medium amounts of pyrite and

galena, small amounts of tetrahedrite, and rare of chalcopyrite have been confirmed in

the polished section of an ore sample taken from the waste dump.

(d) Aurora (II) Deposit

The deposit is situated in a small stream one kilometer southeast of the

Aurora (I) deposit. A collapsed adit exists there, and a part of ore body is exposed at the

entrance of the adit. The host rock is an alternation of dominant black slate and

fine-grained tuff, and the ore body is of stratabound, several tens centimeters in

thickness, extending south to north, dipping 20 degrees to the west, in the alternation

bed. The fine-grained tuff has undergone sericitization, but no significant alteration

zone is associated.

The ore shows a banded structure of black fine-grained sulphide layers and

white layers. The assay result of the ore is 18.7 % Ba, 2.36 ppm Au, 133 ppm Ag, 7.94 %

Zn, 1.28 % Pb. In the polished section, ore minerals are large to medium amounts of

sphalerite, medium amounts of pyrite, and small amounts of tetrahedrite, and the

white part consists of barite, gypsum, and feldspar.

(e) Guadalupe Deposit

The Guadalupe (Salitre Grande) deposit is situated to the south of Salitre

Grande Village in the eastern district, and collapsed adit, shaft and waste dump are

found in both sides of a stream running east to west. The rocks distributed in the area

are slate, lapilli tuff, tuff containing mud-balls. The rocks have partly undergone weak

alteration of silicification and argillization mainly consisting of sericite, but its

alteration zone is narrow.

Ores seen in the waste dump are of massive kuroko type ore, barite rich ore,

and slightly layered ore, etc. The assay result of the massive kuroko type ore is 45.2 %

Zn, 7.51 % Pb, 310 ppm Ag, 0.856 % Cu, 0.55 ppm Au. In the polished section, large

amounts of sphalerite, medium to small amounts of pyrite, galena, and tetrahedrite

have been confirmed. The tetrahedrite is mainly accompanied by galena. Pyrite from a

dump ore sample showing layered structure partly shows framboidal and colloform

textures.

(f) Cruz Blanca Deposit

The deposit is situated in the eastern side of a mountain ridge, one kilometer

south of the Guadalupe deposit, and west of Azulaquez Village. Collapsed shaft, adit,

and waste dump are seen in a wide spread area. The area is underlain by stratified tuff

and partly containing mud-balls like slate. In an outcrop nearby the adit in the

western end area, an outcrop of fine-grained kuroko type ore, 20 meters thick, is seen

in the tuff. Its apparent strike and dip are N 30゜E and 40゜N, but the other parts

show variable in dip. Some outcrops of gossan due to pyrite dissemination are seen all

over the place. The area has undergone weak argillization and partly silicification.

It has been confirmed that a part of the dump ores is of massive, siliceous, and

chalcopyrite bearing. The assay result of the ore from the outcrop shows 24.3 % Zn,

9.51 % Pb, 126 ppm Ag, 1.61 % Ba, and 0.36 % Cu. Under the microscope, the minerals

of the massive ore and fine-grained ore consist of large amounts of sphalerite, medium

amounts of pyrite and galena, and small amounts of tetrahedrite and chalcopyrite, and

furthermore very small amounts of bornite and covelline. Recrystallization of minerals

due to metamorphism has been recognized.

(ii) Vein Type

Vein type mineralized and altered products are seen in the northern

district. The Yerba Buena and San Carlos deposits, and the Velixtla South and some to

the north of Manto Rico deposit have been already known.

(a) Yerba Buena Deposit

The deposit is situated to the north of Salitre Grande Village in the

northeastern district. A submerged adit oriented southeast and waste dumps exist

along a stream. Slate is exposed around the adit, and a hydrothermal brecciated quartz

vein, 1 to 2 meters width, is exposed extending northwest. Some high grade lead and

zinc ores are seen in the dumps. Quartz veins extending N 60゜W and N 80゜W have

been confirmed along a stream about 750 to 1,000 meters northwest of the mine site.

These are possible continuation of the vein in the known mine site.

The assay result of the ore taken from the dump shows 3.46 % Zn, 5.2 % Pb,

116 ppm Au. Pyrite, arsenopyrite, and sphalerite are principally seen, being

accompanied by small amounts of galena and minor amounts of chalcopyrite in the

polished section of the outcrop ore and waste.

(b) San Carlos Deposit

The deposit is situated around 2 kilometers north-northeast of Tlanilpa

Village in the northern end of the district. Collapsed old mine site exists on a mountain

ridge extending north to south. A submerged adit exists along a stream. The area is

underlain by greenish vitric tuff, lapilli tuff, and andesite (Va-3), with intersecting

white quartz veinlets trending north-northeast and northwest in these rocks.

No sample has been assayed in this survey, but CRM has reported assay

result of 2,700 g/t Ag for a sample from this site.

(c) South of Velixtla

Pyrite dissemination and stockwork are seen along some roads and at the

dead end of the upper stream of the El Manto. The veinlets extend northwest and

west-northwest. In the polished section of four specimens, the ores consist mainly of

slightly coarse-grained pyrite, and are accompanied by arsenopyrite or sphalerite and

minor amounts of chalcopyrite.

(d) North of Manto Rico

A vein consisting of calcite, sphalerite, and galena has been confirmed at the

bend point of the El Manto Stream in the andesite (Va-2). It is 50 centimeters in width,

extending east to west and dipping to the south. In the polished section, the ore is

composed of medium amounts of sphalerite, small amounts of pyrite, galena, and

chalcopyrite, and very small amounts of marcasite. The chalcopyrite disease in

sphalerite has been observed.

(iii) Other Mineral Occurrences

The mineral occurrences of La Campana and Otates NW are situated in the

northwestern corner of the district.

(a) La Campana

The occurrence is situated in an outcrop along a road to the northwest of C. La

Campana Mountain. There remained a small-scale excavation. The occurrence is in the

uppermost zone of an alternation of slate and dacitic tuff (Ust). Sulphide mineralized

and silicified fragments in the tuff and a pyrite lens associated with a fissure trending

northwest in the slate are seen. In the polished section of the pyrite lens, the gangue

minerals are filled openings of pyrite aggregation, and some pyrite aggregations form

clots. It is thought that the occurrence is of overlapping of massive sulphide type and

vein type mineralization.

(b) Otates NW

The occurrence is situated on the left bank of a stream running down to the

southwest in the northwestern corner of the district. The area is underlain by schistose

green volcanic rocks (Lsh). The schistose rock around the occurrence is grayish due to

sericitization. Sulphide lenses, several tens centimeters thick, continue intermittently

for several meters long, parallel to the schistosity plane dipping gently to the west.

Some malachite stains are partly seen. In the polished section, the ore consists of

mainly pyrite, being accompanied by small amounts of chalcopyrite filling open spaces

of pyrite grains and cracks.

2 Santiago Salinas Area (detailed survey area)

The district is situated to the southwest of the Aurora Area, occupying the

upper stream of the Paso del Carizo River. Many branch rivers run into the Paso del

Carizo.

(1) Geology and Geological Structure

The district is underlain by the dacite (DCw) and (Vad), occupying about 60

percent of the area, sedimentary rocks (Ms), andesitic rocks (Va-5, Va-6, Vam), and

sedimentary rocks (CFm) of the Pachivia Formation covering a part of the southern

ridge.

The dacite (DCw) is grayish green in their fresh parts, and consisting of large

amounts of vitric groundmass and small amounts of plagioclase phenocrysts. The rocks

are supposedly to be lavas showing lenticular structure, several to several tens

centimeters in length, but partly tuffaceous to the west and south of Santiago Salinas,

probably being autobrecciated-rock. Cleavages, trending north-northwest and gentle

dipping to the west, are significantly developed in the rocks.

The sedimentary rocks (Ms) are of alternations of slate and limestone, and

they have very fluctuated thickness. They also form rhythmical alternations with

lapilli tuff to breccia, to the southeast and south of Santiago Salinas. Their strike and

dip are fluctuated as shown in their random distribution, but their cleavages mostly

dip gently to the west or north, forming folding axis planes.

The andesitic rocks (Va-5) are distributed to the west of Santiago Salinas as

intercalated beds (50 to 60 centimeters in thickness) in the dacite. Weak

autobrecciated structure is seen, showing grayish green in color. They are accompanied

by several beds of mudstone with 10 to 20 centimeters thick, and tuffaceous parts in a

stream to the west of Santiago Salinas. The beds show northwest strike and dip to the

northeast, and their recognized cleavage planes dip to the south to west, therefore both

structures intersect each other.

Va-6 is distributed in the dacite at the northeastern end and southern part of

the district. The rocks are schistose green tuff.

Vam is partly distributed on a ridge in the eastern district. The rocks are

andesitic tuff being accompanied by thin beds of mudstone.

Vad is mainly composed of dacite, being accompanied by thin layers of

andesite. It is possible to be correlated to DCw.

(2) Structural Geology

The geological structure of the whole area of Santiago Salinas is controlled by

an anticline structure having northwest trending axis as shown in the distribution

pattern of the sedimentary rocks (Ms). The strata steeply incline to the northeast in

the southeast of Santiago Salinas, and tend to be gentle dip to the east. In the southern

area, they incline gently to the south to southwest. Accordingly, the upper horizon is

exposed in the east, and the lower horizon is exposed in the west.

(3) Mineralization and Alteration

The mineralized and altered zones confirmed in the survey are situated in the

zone to the northwest of Santiago Salinas (Santiago-NW), to the southeast of Santiago

Salinas (Santiago-SE), and to the south of Santiago Salinas (Santiago-S).

(a) Santiago-NW

The mineralized zone has been confirmed in both sides of a stream in different

forms. That on the right bank (northwestern bank) is a mudstone bed, several

centimeters thick, containing silicified breccias with disseminated fine-grained pyrite

in the dacite. In the polished section, disseminated micro-grained pyrite occurred in

groundmass. The main assay result of the rock is 162 to 337 ppm Zn, and 239 to 401

ppm Ba. That on the left bank (southeastern bank) is a sulphide stockwork in the

dacite. In the polished section, it contains aggregation of fine-grained pyrite, but no

other mineral. The main assay result is 1.00 ppm Ag, and 158 ppm Ba.

(b) Santiago-SE

The mineralized zone has been confirmed in the dacite overlain by an

alternation of slate and lapilli tuff as a stockwork of fine-grained pyrite. The alteration

zone of gossan spreads in the dacite around the mineralized zone. Under the

microscope, no other mineral is confirmed rather than large amounts of pyrite. The

main assay result is 4.85 ppm Ag, 121 ppm Pb, and 154 ppm Zn.

(c) Santiago-S

The alteration zone has been confirmed in three points along a stream

running south to north. They are accompanied by sulphide dissemination and

stockwork in the dacite overlain by alternations of slate and tuff, and belong in a same

series. They are also stratigraphically correlated to Santiago-SE; therefore it is

possible to be continuous occurrence. The main assay result shows, 1.01 % Ba, and 133

ppm Zn.

3 Rancho Viejo Area

The area is situated in the central south part of the Zacualpan area. This area

is corresponded to the upper stream of the Los Sabinas River drainage system. The

Sabinas River runs from north-northwest through the central part of the district. Its

branches are in an east-west system. The topography is generally gentle, and its

altitude is between 1,400 and 1,700 meters. The principal villages in the district are

Tierra Colorada in the northwest, Amate Amarillo in the northeast, Rancho Viejo in

the west, and Tenangillo in the east.

(1) Geology

The district is underlain by volcanic rocks of the Villa Ayala Formation and

overlaying sedimentary and volcanic rocks of the Pachivia Formation.

(i) Villa Ayala Formation

The formation is composed of basalt to andesite (Va), and dacite (Vd).

(a) Basalt to Andesite (Va)

The rock occupies about one third of the whole area in the western district.

The rocks are grayish green to dark green, showing autobrecciated and pillow breccia

to hyaloclastite facies, being accompanied by inclusions and thin layers of calcareous

mudstone. The rock facies is fine-grained aphanitic, and in some cases changes from

that of containing small amounts of plagioclase and pyroxene phenocrysts to

coarse-grained porphyritic. They contain many gas cavities, and show amygdaloidal

textures in the pillow breccia parts. Under the microscope, pseudomorph of mafic

minerals and plagioclase phenocrysts are seen in the fine-grained groundmass.

(b) Dacite (Vd)

The rock exists as a mass, several tens to 200 meters thick and several

hundreds meters long, in the basaltic to andesitic rocks (Va). They contain some

amounts of plagioclase phenocrysts, and their groundmass is grayish green to dark

green and vitric. Cleavage planes developed in their vitric groundmass, and the

boudinage is seen due to accumulation of hard porphyritic lenses. Under the

microscope, small amounts of plagioclase phenocrysts are seen in the altered vitric

groundmass.

The Villa Ayala Formation apparently dips to the west, and trends

north-northeast or north-northwest. A small folding structure recognized in the

hyaloclastite thin bed is a syncline showing overturned sense, showing N 10゜W strike

and 30゜west dip.

(ii) Pachivia Formation

The formation is composed of basaltic to andesitic tuff (CFv), limestone (CFL),

slate (CFs), and alternation of tuff and slate (CFt).

(a) Basaltic to Andesitic Tuff (CFv)

The rock is extensively distributed in the central to northern district. The

most of them is rich in andesite to basalt lapilli, being accompanied by small amounts

of fragments of dacite, calcareous slate, and calcareous sandstone. Its little

groundmass is calcareous. It gradually changes to a thin bed of autobrecciated lava to

hyaloclastite. Intercalated thin bed contains some slate and tuff showing clear bedding

and foliation in many cases.

The foliation is not clear in some brecciated part, but intercalated

sedimentary layers unclearly show the north-northwest and the north-northeast

trends and west and east dips. The trend of cleavages is about same as that of the

layers, but its dip is stably west. The axis of the folding structure in outcrop is

coincident to the cleavage plane.

(b) Limestone (CFL)

The rock is distributed in the eastern and southeastern district. The outcrop

along the Sabinas River in the southeastern district is gray, brecciated and slightly

schistose limestone. The bodies distributed in a north to south extending in the eastern

edge of the district are of alternations with tuff and slate, and some foliation planes

and bedding planes are seen.

(c) Slate (CFs)

The rocks mainly composed of slate (CFs), are distributed around Tierra

Colorada in the northwestern district, extending north to south. The rock mainly

consists of well-foliated black slate, being accompanied by thin layers of sandstone, tuff,

and basaltic autobrecciated lava. The stratum shows the north-northeast strike and

west dip, and the cleavages show the same.

(d) Alternation of Tuff and Slate (CFt)

The rock is distributed around Tierra Colorada in small-scale in the

northwestern district. The rock is dominated by tuff, but generally consists of

alternations of black slate and dacitic tuff, several centimeters to several tens

centimeters in thickness, and andesitic hyaloclastite.

Small folding structure gently dipping to the west and other folding structure

bending cleavage planes and bedding planes exist. The stratum shows the

north-northeast strike and west dip, rarely east dip.

(2) Structural Geology

The distribution pattern of the strata in the whole area of Lancho Viejo is in

the systems trending north to south and north-northwest. In the central south district,

a left lateral fault of northwest to southeast system exists between the Villa Ayala and

Pachivia Formations.

A set of isoclinal anticline and syncline showing north-northwest trend exist

in Amate Amarillo and the Los Sabinas River in the central district.

In a stereo project study, the cleavage planes are concentrated to an area of

north to south strike and west gentle dip, and the bedding planes show same tendency,

but some northeast dip and southeast dip planes also exist.

The dips of the bedding and cleavage generally show westward, and the Villa

Ayala Formation apparently overlies the other formations. However, it is thought that

existence of an overturned folding made this appearance from the following view

points, (1) no thrust fault exists there, (2) the sedimentary material of the Pachivia

Formation contains volcanic fragments from the Villa Ayala Formation, (3) the

limestone of the Pachivia Formation contains middle Cretaceous fossils, (4) the

existence of overturned folding showing the axis of westward dip.

(3) Mineralization and Alteration

No significant mineralized and altered zone exists there, but some small-scale

ones have been confirmed in the Tierra Colorada Stream, Tenangillo River, and small

streams to the south and north of Cerro de Zacahuixtepec in the northern district.

(a) Tierra Colorada Stream

A small-scale hydrothermal pyrite-sphalerite vein, 5 centimeters in width, has

been confirmed in between the Villa Ayala Formation and Pachivia Formation on the

down stream area of the Tierra Colorada (Figure II-1-13). A stockwork gossan and

sulphide exist in the andesitic hyaloclastite body, but no alteration affect extends to the

surroundings. The assay result of the ore is 4.8 % Zn, but no other indication for useful

element. Under the microscope, large amounts of brecciated pyrite and small amounts

of sphalerite filling spaces of breccias are seen. The colloform texture is recognized in

the pyrite and sphalerite.

A sericitized and pyrite disseminated zone has been confirmed in the dacitic

tuff overlain by a dacite body in the upper stream area, but its continuity is poor.

Some sulphide stockwork occurrence with reddish gossan has been also

confirmed in the dacite lava (JR-10) in the same area. Under the microscope, only

pyrite dissemination is seen.

(b) Tenangillo River

A weakly mineralized zone of lenticular and disseminated pyrite has been

confirmed in the slightly fine-grained tuff of the Pachivia Formation in this area.

Under the microscope, only pyrite is seen, but no mineralization extends to the

surroundings.

(c) Cerro de Zacahuixtepec (north of Tierra Colorada)

A sericitized and gossan zone has been confirmed in a small stream to the

south of Cerro de Zacahuixtepec, but its continuity is poor. In a small stream to the

north, some pebbly pyrite is contained in the slate. Under the microscope, some

framboidal and colloform textures remain. It is possible to be sedimentary origin,

because fine-grained pyrite dissemination is seen in between the pebbles.

4 Result of laboratory test (Petrologic chemical assay, X-ray powder diffraction

analysis, fluid inclusion test, isotopic analysis, radioactive age determination)

(1) Petrologic Chemical Assay

Major and minor elements of specimens of typical rock facies have been

assayed, and their petrologic characteristics have been investigated. The assay result

is shown in a table together with geochemical assay result. The result of the

investigation is shown in Figure II-1-14 to Figure II-1-16 in the appendix of the report

as the discrimination diagram, Harker diagram, and spidergram.

(a) Major Elements

In the K2O-SiO2 plot, the volcanic rocks belong to medium K type, and partly

high K type. In the FeO/MgO-SiO2 plot, the most andesite and dacite belong to

calc-alkali type, but the schistose green rock and andesite specimens from drilling

cores are plotted in the tholeiite field.

The schistose sandstone (Lss) is potted in the passive margin field, and

sedimentary rocks from the drilling cores (Us) and (CF) from the Rancho Viejo area is

plotted in the continental arc to active continental margin field.

(b) Minor Elements

In the chondrite normalized pattern diagram, all specimens tend to down to

the right. The characteristic depletion of Nb and Ta, significantly low value compared

with neighbor element, in the volcanic rocks associated with subsidence are not seen

there. From the above-mentioned two factors, it is said that the volcanic rocks of this

area possess some intermediate chemical character in between the central ridge and

island arc volcanic activities.

Followings are some consideration for each rock type.

・Andesite

The elements easily be concentrated in liquid phase such as Ba, Rb, Th have

significant variation. This indicates that the rock is the final product of mixing with

various level of differentiation-stage’s material. Only one different from others is the

specimen JA29, which shows high Nb and Ta content, indicating ocean ridge type. The

specimens FA80 and UA85 show relatively low Ba, Rh, and Th content, indicating

some possibility of a magma type resemble to the ocean ridge type component and

different from other andesite.

The specimens FR3, JA132, and JA125, andesite from the Pachivia Formation,

show relatively high Nb and Ta content, indicating the ocean ridge type, clearly

different characteristic from other andesite including drill core’s specimen.

・Dacite

The rocks show principally same chemical character as that of the andesite,

even there is some range in its liquid phase concentrated element content in the all

specimens. It suggests that the dacite and andesite have been formed from the magma

originated under the same series of tectonic setting. No difference is recognized among

dacite.

・Others

The sandstone, tuff, and green schist show the same pattern as that of the

andesite, even the number of the specimens is small. It therefore suggests that these

rocks also have been formed (or crashed and redeposited), under the same

environment.

・In the chondrite normalized REE pattern, rare earth elements (REE) are also useful

to determine the geochemical significance and to distinguish different rocks. In

addition to that, it is applied to discuss on degrees of fractional chrystallization and

different source material.

It tends to that the light rare earth elements, La, Ce, and Pr, are highly

concentrated in the all specimens compared with chondrite, and the heavy rare earth

elements, Lu, Yb, and Tm, are of low concentration. This suggests that the genetic

environment for the all rocks is not so different.

Three specimens, FR3, JA132, and JA125, show higher concentration of the

light rare earth elements, it is therefore possible that their source material is different

from others.

The dacite shows relatively high concentration of the light rare earth

elements, compared with the case of the andesite, and characteristic low concentration

of Eh. It indicates that the plagioclase in the rock had been crystallized from the dacite

magma, therefore it is possible to interpret that the rock is affected by the fractional

crystallization.

(2) X-ray Powder Diffraction

(i) Measuring Condition

Total 102 specimens for the measurement have been taken from the known

mineral occurrences, alteration zones, and their vicinity.

(ii) Measurement Result

The minerals detected by the test are mostly quartz, albite, chlorite, sericite,

and calcite, followed by dolomite and pyrite. Potash feldspar, kaolinite, paragonite,

gypsum, barite, jarosite, galena, sphalerite, epidote, pyroxene, and amphibole have

been rarely detected.

Judging from its mineral assemblage, the chlorite-sericite-albite alteration is

ubiquitously seen in the Aurora Area. The alteration associated with the Tizapa type

massive sulphide mineralization is accompanied by strong sericitization in many cases.

The intensity of the sericitization, therefore, has been investigated by making

contouring map showing the relative volume of sericite as shown in Figure II-1-17.

The sericite rich parts in the Aurora Area are the northern and southern parts

of the Manto Rico deposit, Tlanilpa mineral occurrence to the southeast of MJZC-1,

Capire deposit, eastern part of Aurora II deposit, and southern part of Santiago

Salinas, etc., and they tend to show 3T-type. In the Santiago Salinas area, sericite rich

zone is accompanied by kaolinite and gypsum, and Tlanilpa is accompanied by

paragonite. It is well known in the Hokuroku kuroko region in Japan, that paragenesis

albite in vicinity areas of the deposits is not detected by X-ray test. In the Aurora Area,

albite is detected in minor volume or not detected in the Tlanilpa mineralized zone,

Capire deposit, Aurora I and II deposits, and Santiago Salinas.

Sericite is clearly minor in the Rancho Viejo area compared with that of the

Aurora area. The specimen not detected sericite is only of the tuff nearby Tierra

Colorada. A small amount of gypsum has been detected in the Tenangillo River mineral

occurrence.

(3) Fluid Inclusion Test

(i) Method

The specimens taken from mineral occurrences and alteration zones have

been tested. Some clear specimens have been selected, and their both sides have been

polished for determination. The homogenization temperature measurement has been

performed using the microscope heating apparatus TH-600 made by Linkam and the

temperature rising rate around homogenized temperature was 1.0 to 0.1゜C per

minute. The homogenized temperature for one specimen has been measured twice, and

no leaking problem was confirmed. The compensation of temperature has been

performed using benzaminde (163゜C) and sodium nitrate (305゜C).

The salinity measurement has been performed using liquid nitrogen, cooling

down to -60゜C. After the fluid inclusion was frozen, the temperature was gradually

increased until the frozen material was completely melted, and the temperature was

measured. The salinity was obtained from the standard detection lines already

prepared.

(ii) Measurement Result

Figure II-1-18 and Table II-1-4 show the measurement result.

The homogenized temperatures of the associated minerals from Capire

deposit, Aurora II deposit, and Manto Rico deposit and all the known massive sulphide

type occurrences, show bimodal distribution. The low-side temperature shows the

frequency peak in between 170゜and 190゜C, that of high-side temperature in between

210゜and 230゜C. The alteration zone of the Capire deposit (FA-3), mineral occurrence

of Santiago Salinas, and mineral occurrence of the northern part of Metlixtapa (JR-88)

show same frequency distribution pattern. In contrast, the alteration zones of the

Guadalupe deposit, north of Aurora I deposit, and south of Aurora II deposit form a

single group, concentrating around 150゜to 170゜C. The salinity shows in between 2 to

4 percent, but that of Aurora II is below 1 percent.

It is thought that the variability of the homogenized temperature occurred

because the later regional metamorphism overlapped massive sulphide type

mineralization.

The homogenized temperature of the ore from the vein-type Yerba Buena

deposit is clearly higher than that of the massive sulphide type, and the average

temperature is 292゜C. The frequency distribution is near to a single population.

Accordingly, it probably keeps the temperature record of ore forming stage. The

homogenized temperature of the lead-zinc vein to the north of the Manto Rico deposit

(FAO-2) also forms a single group, but its temperature is low, 170゜C in average. The

salinity is 8 percent, clearly higher those of others.

The specimen from La Campana shows a single frequency distribution,

concentrating nearly 220゜C homogenized temperature. The size of the gas cavities is

variable, suggesting the boiling. The specimen from Velixtla South mineral occurrence

(J100701) shows fluctuated temperature distribution in between 190゜to 260゜C,

indicating overlapping hydrothermal activities.

In the Rancho Viejo area, the zinc vein (FRO-1), showing high grade of 4.8

percent, in the mineral occurrence on the downstream area of the Tierra Colorada

shows a single frequency distribution of the homogenized temperature, having 229 °

C in average. The salinity is 3 to 4 percent, a little fluctuation.

The specimen from a small stream in the north of Cerro de Zacahuixtepec

contains some pyrite, and its homogenized temperature is of bimodal distribution,

resemble to that of the massive sulphide type.

(4) Isotopic Analysis

The specimens for the measurement have been taken around the mineral

occurrence parts. The oxygen isotopes of the whole rock silicate have been measured

for 31 specimens, and the carbon and oxygen isotopes of the carbonate in the

calcareous rocks for 6 specimens. Table II-1-5 and Figure II-1-18 show the result.

The oxygen isotope ratio ranges between 10.1 per mill and 21.0 per mil. The

andesitic rocks show 10.1 to 15.9 per mil, and dacitic rocks show slightly higher 10.3 to

21.0 per mil. The oxygen isotopic value for common volcanic rocks is around 10 per mil,

and that for metamorphic rocks is between 10 per mil and 25 per mil. It is thought that

the volcanic rocks in this area are in a group of being undergone metamorphism in

sense of isotopic; even they preserve some original textures.

The oxygen isotope ratio due to alteration varies due to the isotopic exchange

reaction between rock and hydrothermal liquid. If hydrothermal liquid originated from

marine water attributes in large amounts and long time, it is expected that the oxygen

isotopic ratio of rock would be decrease. As the result of the investigation of the isotopic

measurement of the area, no significant change in the isotopic values by alteration, but

some decrease is recognized around the Aurora deposit. The background value of the

andesite around the Capire and Aurora deposits is 12 to 13 per mil, but that of around

the Aurora I deposit show 10 to 11 per mil, apparently getting a little. The isotopic

background value of the dacite in the Aurora II deposit is 18.5 per mil, but nearer to

the deposit it is getting down to 10.3 per mil, reflecting hydrothermal activity.

The isotopic analysis has been performed for the carbonate from the limestone

near by the ore horizons. The oxygen isotopic ratio ranges between -8.0 per mil and

-13.1 per mil. This low value is lower than that of common sedimentary rocks, 10 per

mil to 30 per mil, and close to that of the calcite contained in the altered volcanic rocks

from Wairakei, therefore this is due to the metamorphism or others.

The carbon isotopic value ranges between -12.4 per mil and +1.7 per mil.

Presuming from the oxygen isotopic value, this is same as the hydrothermal calcium

carbonate, accordingly it is thought that the measured calcite composing the limestone

has been completely changed by the metamorphism and from hydrothermal liquid.

(5) Radioactive Age Determination

The radioactive age determination has been performed for two andesite

specimens (Va-1, Va-4) and one dacite specimen (DCe) from the Aurora area applying

the Ar-Ar method. The analysis was commissioned to Activation Laboratories Ltd. in

Canada.

Table II-1-6 shows the determination result.

Determined age of Va-1 andesite(JA-50) is 92.6 ± 1.2Ma, Va-4

andesite(FA-49) is 118.8±8Ma, and DCe dacite is 93.8±1.9Ma. The age value of

Va-4 andesite is supposed to include some error because of its low Ar content.

The age of these rocks from Villa Ayala Formation is estimated to be early Cretaceous,

in consideration of metamorphism.

Representative Ore Showings

Capire AuroraAuroraGuadalupeCruz BlancaManto RicoTlanilpaSan CarlosYerba BuenaLa CanpanaOtates NWVelixtla SSantiago Salinas NW Santiago Salinas SESantiago Salinas SMetlixtapa N

JR-26JR-26 2828JR-26 28FRO-1FRO-1FRO-1

JR-10JR-10JR-10

JR-38JR-38JR-38

LEGEND

Pachivia Formation CFm: Calcareous slate, limestone

Villa Ayala FormationDCw: Plagio phyric Dacite tuffMs: Slate, LinestoneVam: Andesitic tuff with mud ballVa-5: Andesite lava, tuffVa-6:Foliated andesiteVad:Dacite with Andesite

Alteration zone

Bedding plane

Cleavage plane

Geological section

KK

PgPgPg

GpGpGp

GpGpDo

: Sericite (3T)

: Kaolinite

: Palagonite

: Gypsum

: Dolomite

Sericite X0.1cps

KK

KK

KK

PgPgPg

PgPgPg

PgPgPg

PgPgPg

PgPgPg

DoDoDo

GpGpGp

GpGpGp

,,

GpGpGp

LEGEND

GL-A

Mineral Quartz

Number 20 個

Max. 163 ℃

Min. 144 ℃

Average 153.2 ℃

S.D. 4.2

Temperature(℃)

YB-2

Mineral Quartz

Number 20

Max. 325 ℃

Min. 241 ℃

Average 292.0 ℃

S.D. 20.6Temperature(℃)

Capire

Mineral Quartz

Number 20 個

Max. 233 ℃

Min. 169 ℃

Average 206.6 ℃

S.D. 17.2Temperature(℃)

MtR

Mineral Quartz

Number 20 個

Max. 222 ℃

Min. 165 ℃

Average 197.8 ℃

S.D. 16.7Temperature(℃)

AU-II

Mineral Quartz

Number 20 個

Max. 251 ℃

Min. 173 ℃

Average 217.2 ℃

S.D. 23.0Temperature(℃)

Frequency

Frequency

Fig.Ⅱ－１－１８　Result of fluid inclusion test (1)

Frequency

Frequency

Frequency

0123456789

10111213141516

120 130 140 150 160 170 180 190 200 210 220

0

1

2

3

4

5

6

7

230 240 250 260 270 280 290 300 310 320 330

0

1

2

3

4

5

6

7

150 160 170 180 190 200 210 220 230 240 250

0

1

2

3

4

5

140 150 160 170 180 190 200 210 220 230 240

0

1

2

3

4

5

6

160 170 180 190 200 210 220 230 240 250 260

FA-3

Mineral Quartz

Number 20 個

Max. 216 ℃

Min. 155 ℃

Average 183.9 ℃

S.D. 16.4Temperature(℃)

FAO-1

Mineral Quartz

Number 20 個

Max. 248 ℃

Min. 196 ℃

Average 229.5 ℃

S.D. 13.1Temperature(℃)

J100701

Mineral Quartz

Number 20 個

Max. 261 ℃

Min. 194 ℃

Average 232.6 ℃

S.D. 17.8Temperature(℃)

Campana

Mineral Quartz

Number 20 個

Max. 235 ℃

Min. 212 ℃

Average 223.0 ℃

S.D. 5.9Temperature(℃)

J88

Mineral Quartz

Number 20 個

Max. 235 ℃

Min. 162 ℃

Average 198.4 ℃

S.D. 19.0Temperature(℃)

Frequency

Frequency

Frequency

Frequency

Frequency

Fig.Ⅱ－１－１８　Result of fluid inclusion test (2)

0

1

2

3

4

5

6

7

8

9

130 140 150 160 170 180 190 200 210 220 230

0

1

2

3

4

5

6

7

8

160 170 180 190 200 210 220 230 240 250 260

0

1

2

3

4

5

6

7

8

170 180 190 200 210 220 230 240 250 260 270

0123456789

10111213

190 200 210 220 230 240 250 260 270 280 290

0

1

2

3

4

5

6

140 150 160 170 180 190 200 210 220 230 240

FA0-2

Mineral Calcite

Number 20 個

Max. 188 ℃

Min. 143 ℃

Average 172.2 ℃

S.D. 10.8Temperature(℃)

F1024

Mineral Quartz

Number 20 個

Max. 196 ℃

Min. 162 ℃

Average 180.1 ℃

S.D. 8.4Temperature(℃)

FRO-1

Mineral Calcite

Number 20 個

Max. 242 ℃

Min. 215 ℃

Average 229.3 ℃

S.D. 7.6Temperature(℃)

JR-38

Mineral Calcite

Number 20 個

Max. 231 ℃

Min. 163 ℃

Average 194.2 ℃

S.D. 17.2Temperature(℃)

Santiago SE

Mineral Quartz

Number 20 個

Max. 189 ℃

Min. 125 ℃

Average 164.3 ℃

S.D. 16.3Temperature(℃)

Frequency

Frequency

Frequency

Frequency

Frequency

Fig.Ⅱ－１－１８　Result of fluid inclusion test (3)

0

1

2

3

4

5

6

7

8

120 130 140 150 160 170 180 190 200 210 220

0

1

2

3

4

5

6

7

8

9

140 150 160 170 180 190 200 210 220 230 240

0123456789

1011

190 200 210 220 230 240 250 260 270 280 290

0

1

2

3

4

5

6

7

8

150 160 170 180 190 200 210 220 230 240 250

0

1

2

3

4

5

6

7

8

9

100 110 120 130 140 150 160 170 180 190 200

Santiago NW

Mineral Quartz

Number 20

Max. 274 ℃

Min. 205 ℃

Average 244.9 ℃

S.D. 16.6Temperature(℃)

FA1021

Mineral Quartz

Number 20

Max. 203 ℃

Min. 160 ℃

Average 178.0 ℃

S.D. 11.2Temperature(℃)

Fig.Ⅱ－１－１８　Result of fluid inclusion test (4)

Frequency

Frequency

0

1

2

3

4

5

6

7

190 200 210 220 230 240 250 260 270 280 290

0123456789

10

140 150 160 170 180 190 200 210 220 230 240

405000E 406000E 407000E 408000E 409000E 410000E 411000E 412000E 413000E 414000E 415000E

405000E 406000E 407000E 408000E 409000E 410000E 411000E 412000E 413000E 414000E 415000E

205

90

00N

2

058

00

0N

205

70

00N

2

056

00

0N

205

50

00N

2

054

00

0N

205

30

00N

2

052

00

0N

205

10

00N

205

90

00N

2

058

00

0N

205

70

00N

2

056

00

0N

205

50

00N

2

054

00

0N

205

30

00N

2

052

00

0N

205

10

00N

1 NA49 schistose coarse tuff 405945 2057670 ◎ △ ・ ・ △ ○ △

2 NA55 altered andesite 407595 2056493 ○ △ ・ △ ○ △ ○ ・ intersertal texture

3 FA49 brecciated pyroxene andesite 410015 2052055 ・ △ △ △ ・ △ ・ intersertal texture

4 FA87 very fine sandstone 405004 2057666 ◎ △ ・ △ ・

5 FA84 altered dacite (lava) 408370 2057360 ◎ ・ ・ ・ △ ・ felsitic texture

6 FA80 altered andesite 408230 2056700 ・ △ ・ ・ ○ ・ △ △ intersertal texture

7 JA15 epidote chlorite schist 405958 2058264 △ ・ ○ △ ○ ・ weakly lepidoblastic texture

8 JA45 slate 408245 2054052 ◎ ・ △ with quartz-calcite vein

9 JA64 altered pyroxene andesite 408525 2053715 ○ ○ ・ ・ ・ ○ △ ・ △ intersertal texture

10 JA18 shistose dacite tuff 405395 2055235 ◎ △ △ ・ ・ ・ lepidoblastic texture

11 JA50 olivine bearing pyroxene andesite 409201 2054675 ・ ○ ○ ・ ・ △ ・ ・ intersertal texture

12 JA85 schistose fine sandstone 410793 2053192 ○ ・ △ ・ ・ △ ・ weakly lepidoblastic texture

13 JA96 altered dacite (tuff) 411925 2051935 ◎ △ ・ ・ ・ △ ・ felsitic texture

14 JA125 hornblende pyroxene andesite 414920 2054035 ・ △ △ ・ ○ ・ △ ・ △ ・ brecciated and intersatal texture

15 JA139 altered andesite 414920 2054035 △ △ ・ ・ △ ・ ○ △ intersertal texture

16 JA141 schistose andesite 410925 2057045 ○ △ ・ △ △ ・ lepidoblastic texture

17 JR15 schistose fine sandstone 408706 2044741 ◎ ・ △ ・ ・ △ ・ lepidoblastic texture

18 UA24 brecciated altered andesite 405549 2055173 △ ○ ・ ・ ・ △ brecciated and intersatal texture

19 UA46 schistose fine sandstone 407128 2055975 △ ・ △ ・ ○ △ lepidoblastic texture

20 UA83 schistose altered andesite 411832 2056189 △ △ △ ・ ○ △ lepidoblastic texture

21 UA85 altered andesite 410645 2052370 △ △ △ △ ・ △ ・ intersertal texture

22 UA130 schistose altered tuff 410190 2058615 △ △ △ ○ ・ ・ △ strongly altered

23 UA143 shistose dacite tuff 406612 2053258 ○ △ △ ・ ・ ・ lepidoblastic texture

24 UR32 slate 409212 2041565 ◎ ・ △

25 FR1 altered andesite 410188 2041993 ○ △ ・ △ △ △ intersertal texture

26 FR3 altered basalt 410330 2042725 ・ ◎ △ ・ △ ・ pilotaxitic texture

27 FR4 dacite 410180 2042705 ◎ △ ・ ・ ・ ・ felsitic texture

28 FR9 shistose dacite tuff 410058 2043878 ○ △ △ ・ △ ・ strongly altered

29 FR24 brecciated altered andesite 410710 2045735 ○ △ ・ ・ ・ ○ △ relativery fresh cpx bearing

30 FA8 pyroxene andesite 411150 2053730 △ △ △ △ ・ △ △ intersertal texture

31 FA9 altered dacite (tuff) 411275 2053810 ◎ △ ・ ・ ・ ○ △

32 FA10 shistose dacite tuff 408446 2057241 ○ △ △ ・ ・ ○ △ lepidoblastic texture

33 FA13 altered andesite (tuff) 408650 2058150 △ △ ・ △ △ △ △ strongly altered

34 FA19 shistose dacite tuff 405618 2054649 ◎ ・ ○ ・ ・ ・ △ lepidoblastic texture

35 FA21 altered dacite (tuff) 406220 2054360 △ ・ ・ ・ ・ ○ △

36 FA30 limestone (biomicrite) 406620 2054785 ・ ◎ biomicrite

37 FA47 very fine sandstone ・siltstone 409561 2052401 ○ ・ △ △ weakly shistose texture

38 FA57 altered andesite (tuff) 412313 2054141 ○ ○ ・ △ ・ △ △

39 FA62 schistose andesite tuff 413620 2055330 △ ○ ・ △ ・ △ △

40 FA72 altered andesite (tuff) 411890 2057435 △ ○ ・ △ ・ △ △

41 FA79 altered andesite (tuff) 409315 2056935 △ △ ・ △ ・ ○ △

42 BR30 slate 414580 2060950 ◎ ○ △ △ lepidoblastic texture

43 CR7 strongly alterd andesite 404717 2050850 ・ ・ △ ○ ・ strongly altered

44 DR4 slate 400914 2043679 ◎ ○ △ ・ lepidoblastic texture

45 ER4 quartz sericite schist 397426 2060253 ◎ △ ○ △ △ △ lepidoblastic texture

Legend; ◎,abundant; ○, common; △, minor; ・rare

qz:quartz, pl:plagioclase, am:amphibole, opx:ortho pyroxene, cpx:clino pyroxene, ol:olivine

se: sericite, chl:chlorite, ca:carbonate mineral (mainly calcite), opa:opague minerals

Table Ⅱ－１－１(1) Result of microscopic observation(thin section)

No.SampleNo.

Rock Name Note

MineralsCoordinates

UTM-E UTM-N qz pl K-f am opxcpx ol opase chlepi ca

Note

UTM-E UTM-N py As Mc sph gn cp Th Bo ilm Ba Cv Rt(others)

1 CB-1 Cruz Blanca Ｍａｓｓｉｖｅ　ｏｒｅ 413800 2054140 ○ ◎ ○ △ △ Schistose

2 CB-3 Cruz Blanca Ｍａｓｓｉｖｅ　ｏｒｅ 413700 2054130 ○ ◎ ○ △ △ ・ △ Schistose recrystalization

3 GL-A Guadalupe Barite, massive ore 413630 2054870 △ ◎ ○ ○ Colloform、framboidal

4 GL-B Guadalupe Ｍａｓｓｉｖｅ　ｏｒｅ 413475 2054960 △ ◎ △ △

5 GL-C Guadalupe Band Ｍａｓｓｉｖｅ　ｏｒｅ 413630 2054870 △ ◎ ○ ・ ○

6 YB-1 Yerba Buena Brecciated ore 413500 2056480 ◎ △ ○ △ ・ Chalcopyrite disease

7 J-101406 Santiago NW Siliceous Breccia 408040 2053945 ○ ・

8 JA-43 Santiago NW Siliceous Breccia 408040 2053945 ○ ・

9 J-102216(1) Metlix E Net/Film pyrite 411908 2052037 ◎

10 J-102810(1) Salitre Chiq Disseminated pyrite 413259 2052575 ◎

11 J-103007 Salitre Chiq Net/Film pyrite 413390 2052335 ◎

12 J-100902 Velixtla Net/Film pyrite 408950 2058400 ◎

13 J-100905(2) Velixtla Net/Film pyrite 409140 2058615 ◎

14 JA-88 Aurora S Fine Net pyrite 410783 2052722 △

15 J100701 Otates W Vein 405493 2057963 ◎ ◎ ○

16 FAO-1 Manto R. /S Band pyrite 408443 2057228 ◎

17 Mt R（outcrop) Mant.R Band pyrite 408470 2057400 ◎

18 Mt R Mant.R Ba-Massive band ore 408500 2057380 △ ○ △ △ ○ ・

19 Capire Capire Ｍａｓｓｉｖｅ　ｏｒｅ 410625 2054615 ○ ◎ ○ △ Colloform、framboidal

20 Santiago SE Santiago SE Py-Sph NET/py 408875 2052975 ◎ ・

21 Santiago NW Santiago NW Pyrite Net 408039 2053916 ◎

22 FAO-2(Manto N)Manto.R U Vein 408425 2057895 △ ・ ○ △ △ Chalcopyrite disease

23 Otates Otates Pyrite lens 405325 2057918 ◎ △

24 C Campana C Campana Pyrite lens 407081 2058147 ◎

25 FA1017(2) Santiago SE Pyrite Net 408920 2052905 ◎ ・

Legend; ◎,abundant; ○, common; △, minor; ・rare

Py:pyrite, As:arsenopyrite, Mc: marcasite, Sph:sphalerite, Gn:galena, Cp:chalcopyrite, Th:tetrahedorite,

Bo:bornite Po:pyrrhotite, Cv:covelline, Ba:barite, Rt:rutile

Table Ⅱ－１－１(2) Result of microscopic observation(Polished section)

Ore minerals

No. Sample No Location Sample Type

Coordinates

Note

UTM-E UTM-N Py As Mc Sph Gn Cp Th Bo Po Ba Cv Rt(others)

26 FA1021 AuroraⅠ N Disseminated pyrite 410983 2055021 ○

27 FA1024(1) AuroraⅡ S Pyrite Net 412131 2053448 △ ・

28 FA-07 Tlanilpa Pyrite Net 410085 2056105 ◎ Colloform

29 UA-129 Velixtla Pyrite Net 409868 2058877 ○ △ ・

30 UA-92 AuroraⅡ S Disseminated pyrite 412000 2052955 △

31 UA-131 Tlanilpa Disseminated pyrite 412000 2052955 △

32 NA-29 Tlanilpa Pyrite Net 410103 2056187 ◎

33 NA-57 Velixtla Disseminated pyrite 409465 2058965 ○ ・ ・

34 FRO-1 Rancho V.NE Pyrite Net 409970 2043875 ◎ ○ ・ Colloform

35 JR-10 Rancho V.N Disseminated pyrite 408625 2043998 ○

36 JR-25 A. Tenanguillo Pyrite Net 411300 2043460 △

37 JR-26 A. Tenanguillo Pyrite Net 411300 2043460 ○

38 JR-28 A. Tenanguillo Disseminated pyrite 411400 2043465 ○ ・

39 JR-38 Tierra C. N Pyrite Net 409458 2045732 ◎ Colloform、framboidal

40 Aurora-1(AR-6) Aurora Ⅰ Ｍａｓｓｉｖｅ　ｏｒｅ 411100 2054540 ○ ◎ ○ ・ △

41 J102106 Aurora S Disseminated pyrite 410842 2053310 △ ○

42 J102117(2) Aurora S Brecciated ore 410770 2052745 △

43 J102216(2) Metrixapa E Disseminated pyrite 411908 2052037 ○ Colloform

44 J102505 Metrixapa E Disseminated pyrite 412410 2052060 ○

45 J100109 Yerba buena NW Vein 412674 2056979 ○ ○ △ ・ ・ ・ Chalcopyrite disease

46 AR-10 Aurora Ⅱ Barite, Massive ore 411793 2054039 ○ ○ ○ △ ○

Legend; ◎,abundant; ○, common; △, minor; ・rare ◎ ○ △ ・

Py:pyrite, As:arsenopyrite, Mc: marcasite, Sph:sphalerite, Gn:galena, Cp:chalcopyrite, Th:tetrahedorite,

Bo:bornite Po:pyrrhotite, Cv:covelline, Ba:barite, Rt:rutile

Sample Type

Table Ⅱ－１－１(3) Result of microscopic observation(Polished section)

Ore minerals

No. Sample No Location

Coordination

No. Sample No. UTM-E UTM-NAu

(ppm)Ag

(ppm)Cu

(ppm)Pb

(ppm)Zn

(ppm)Ba

(ppm)Fe

(ppm)S

(ppm)

1 CB-1 413800 2054140 0.39 126 3630 95100 243000 16100 47800 206500

2 GL-B 413475 2054960 0.55 310 8560 75100 452000 7650 27900 289000

3 YB-1 413500 2056480 0.07 116 481 52000 34600 9 160000 234000

4 J-101406 408040 2053945 < 0.01 0.90 29 87 337 401 51500 51300

5 JA-43 408040 2053945 0.03 0.60 25 76 162 239 24300 14800

6 J-110509(2) 408438 2052518 < 0.01 0.60 13 13 133 10120 95900 127000

7 JA-88 410783 2052722 < 0.01 0.30 14 25 44 147 15400 15400

8 Mt.R (outcrop) 408470 2057400 < 0.01 0.90 23 11 82 39 238000 294000

9 Mt.R 408500 2057380 0.84 550 6950 8070 17000 531000 1740 18800

10 Capire 410625 2054615 1.67 1900 4720 50900 127000 367000 11000 88400

11 Santiago SE 408875 2052975 < 0.01 4.85 25 121 154 17 103000 110700

12 Santiago NW 408039 2053916 < 0.01 1.00 16 22 85 158 202000 264000

13 FA-07 410085 2056105 < 0.01 0.90 9 27 71 467 76500 73600

14 FRO-1 409970 2043875 < 0.01 0.30 42 2070 48200 34 242000 348000

15 JR-38 409458 2045732 < 0.01 0.80 42 23 78 43 155000 184000

TableⅡ－１－２　Result of ore grade assay

Qz Ab Kf Sm Ha K Ch S S3 Pg Gp Ba Ja Ca Do Py Gn Sph Px Hb Ep

1 Dacite 410285 2054495 ○ △ △ △

2 Slate>tuff 410500 2054720 ○ ○ △ △ altered

3 Tuff 408446 2057241 ○ ○ ○ ○ ○ ・ △ ・

4 Dacite 408365 2057590 ○ ○ △ △

5 And tuff 408474 2057947 ○ ・ ◎ ○ ◎

6 Andesite 409140 2058025 △ ◎ ○ ○ ・ ・

7 Dacite 406084 2054475 ○ △ ○ △ ・ ・

8 FA-21 And tuff 406220 2054360 ○ ○ ○ △ △ ・

9 FA-32 Dacite 409465 2052710 ○ ○ ・ ・ saponite?

10 FA-33 Dacite tuff 409522 2052573 △ ・ △ △ ・ ○

11 FA-34 Dacite 408884 2052946 ○ ◎ △ ・ ・ ・

12 FA-36 Dacite 409069 2052502 ◎ △ △ ・

13 FA-37 Dacite 408710 2052070 ○ ○

14 FA-43 Dacite 411069 2054760 △ ○ ○ ・ ・

15 FA-44 Tuff 411033 2054943 ○ ・ ○ △ ・

16 FA-45 Tuff 411002 2055180 ○ ・ ○ △ ・

17 FA-48 Tuff 409667 2052163 △ △ ○ ・ ・ ・ ・

18 FA-53 Dacite tuff 412111 2053964 ○ △ ・ ○

19 FA-54 And tuff 412070 2054145 ○ ・ △ △ △

20 FA-55 Dacite 412061 2054335 ◎ ・ △ △

21 FA-64 Calc. Tuff 414650 2055585 ・ ・ △ ・ ◎

22 FA-75 Lapilli tuff 410665 2054135 ○ △ △ ・ △ ・

23 FA-76 Andesite 409880 2056180 △ ○ ○ ・ ・ ・

24 FA-79 Andesite 409315 2056935 △ △ ○ ・ △

25 FA-10/17(3) Andesite 408760 2052000 ○ △ △ △ ・ △

26 FA-10/21(1) Andesite 410983 2055021 ○ ○ ・ pyrite diss

27 FA-10/24(1) Dacite 412131 2053448 ○ ○ ・ △ △ ・

28 FA-10/24(2) Lapilli tuff 412098 2053800 ○ ○ △ ○ ・

29 FA-10/28(1) Dacite 412800 2054700 ○ ◎ ・ ・

30 FA-10/28(2) Slate>tuff 413208 2054807 ○ ◎ ・ ・ ・

31 FA-10/28(3) Calc. Tuff 413355 2054805 △ △ ○ ・ ◎

32 FA-10/29(1) Dacite 413332 2055254 ○ ・ ・ △ ・

33 FA-11/7(1) Andesite 409515 2056440 ○ △ ◎ ○ △ ・

34 FA-11/7(2) Dacite 409515 2056640 ○ △ △ ○ ○

35 FA-11/7(3) Andesite 409395 2057080 ・ △ ◎ △ △Legend; ◎,abundant; ○, common; △, minor; ・rare Qz:quartz, Ab:albite, Kf:K feldspar, Sm:smectite, Ha:halloysite, K: kaolinite, Ch:chlorite, S;sericite,S3;sericite(3T), Pg:palagonite, Gp:gypsum, Ba:barite, Ja:jarosite, Ca:calcite, Do: dolomite, Py:pyrite, Gn:galena, Sph:sphalerite, Px:pyroxene, Hb:horblende, Ep:epidote

Clay MineralsNo. Sample No,

FA-1

Coordinates

UTM-E

Rock nametype

Sulphate MRemarks

UTM-N

Table Ⅱ－１－３ Result of X-ray diffraction(1)

FA-12FA-16

Silica M

Detected Minerals

Other MineralsFeldspar M

FA-3FA-10 FA-11

FA-20

Qz Ab Kf Sm Ha K Ch S S3 Pg Gp Ba Ja Ca Do Py Gn Sph Px Hb Ep

36 FA-41-D Dacite 410020 2057395 ○ ・ △ ○

37 FR- 1 Andesite 410188 2041993 △ △ △ ・ ・ ・

38 FR- 9 Tuff 410058 2043878 △ △ △ ・ ○

39 FR- 12 Dacite 409372 2043925 ○ ・ △ ・

40 FR- 16 Tuff 409470 2045080 ○ △ ・ △

41 FR- 19 Dacite 409065 2044615 ◎ ・ △

42 FRX- 1 Andesite 410550 2042570 △ ・ ・ △ △ ○

43 J- 100902 Ailtered Dc 408950 2058400 ○ ○ ・

44 J- 100905 Andesite 409140 2058615 △ △ △ △ ・ △

45 J- 102511 Dacite 412445 2052395 ○ ○ ・ △ ・ ・

46 J- 110509 Dacite 408438 2052518 ○ ・ ・ △ ○

47 J- 102810(1) Dacite 413259 2052575 △ △ △ △ ・ ・ △

48 JA- 44 Dacite 408100 2054000 ○ ◎ ・ ・

49 JA- 57 Slate 408455 2053250 ○ ・ ◎

50 JA- 63 Tuff 408470 2053635 ○ ・ ○ △

51 JA- 72 Dacite 408256 2052635 ○ ○ ・ ○

52 JA- 83 Dacite 410925 2053440 ○ △ △ ・ ・ ・ ・

53 JA- 90 Breccia 410937 2052559 ○ ◎ ・ ・

54 JA- 93 Tuff 411410 2052310 △ ・ ◎ ・ ○

55 JA- 123 Andesite 414345 2054490 ・ ・ ・ ○ △ ◎

56 JA- 137 Dacite 412653 2056617 ○ ◎ ・ ・ △

57 JA- 138 Andesite 412630 2056925 ○ △ ○ ・ ・

58 JA- 146 Tuff 410563 2054127 ○ ・ ○ △ ○

59 JA- 148 Tuff 413735 2054775 ○ ◎ △

60 JR- 10 Dacite 408625 2043998 ○ △ △ △ ・

61 JR- 21 Andesite 411040 2045085 △ ・ ・ △ ◎

62 JR- 25 Slate 408812 2044721 ・ △ ・ △ ○ ・

63 JR- 26 Slate 411300 2043460 ・ ・ △ △ ◎ ・

64 JR- 28 Slate 411400 2043465 △ ・ △ ・ ・ △

65 JR- 38 Andesite 409458 2045732 ・ △ ・ ・ ・ ・ ○

66 NA- 31 Andesite 410150 2056200 ○ △ ・ △

67 NA- 39 Tuff 410696 2056895 △ ○ △ ・ ・ ○

68 NA- 45 Tuff 405624 2057871 ○ ・ ・ ・ ◎ ・

69 NA- 61 Andesite 408245 2058332 ○ ◎

70 Santiago NW Dacite 408039 2053916 △ ・ ・ ・ ・ ○ ○ alteredLegend; ◎,abundant; ○, common; △, minor; ・rare Qz:quartz, Ab:albite, Kf:K feldspar, Sm:smectite, Ha:halloysite, K: kaolinite, Ch:chlorite, S;sericite,S3;sericite(3T), Pg:palagonite, Gp:gypsum, Ba:barite, Ja:jarosite, Ca:calcite, Do: dolomite, Py:pyrite, Gn:galena, Sph:sphalerite, Px:pyroxene, Hb:horblende, Ep:epidote

No. Sample No, Sulphate M

Table Ⅱ－１－３ Result of X-ray diffraction(2)

Other Minerals

UTM-E UTM-N

CoordinatesSilica M Feldspar M Clay Minerals

Detected Minerals

RemarksRock name

type

Qz Ab Kf Sm Ha K Ch S S3 Pg Gp Ba Ja Ca Do Py Gn Sph Px Hb Ep

71 UA- 54 Andesite 408245 2053200 △ △ ○ ・ ・ ・

72 UA- 55 Tuff 408845 2053033 ○ △ ○ △

73 UA- 57 Tuff 409380 2053586 ○ △ ◎ △ △

74 UA- 59 Tuff 409968 2053576 △ ・ ・ △ ・ ・ ・

75 UA- 61 Tuff 410335 2053511 △ ○ ○ ・ ○

76 UA- 65 Dacite 410971 2053645 ○ △ △ ・

77 UA- 66 Andesite 410963 2053886 ○ ○ △ ・ ・

78 UA- 73 Tuff 410978 2056273 ○ △ ○ △ △

79 UA- 74 Andesite 410985 2054159 ○ D ○ ・ ・

80 UA- 104 Andesite 413735 2053878 ・ △ △ ○ ・ △

81 UA- 106 Tuff 413686 2054082 △ ・ ○ △ ○

82 UA- 108 Andesite 414217 2053787 ・ △ △ ・ ◎ ・

83 UA- 109 Andesite 414297 2053922 △ ・ △ △ △ △

84 UA- 111 Sandstone 414709 2054390 △ △ ◎ ・

85 UA- 113 Dacite 411743 2053843 ○ ・ ◎ △ ○

86 UA- 114 Tuff 412286 2053765 ○ △ ○ ・

87 UA- 115 Dacite 412540 2053652 ◎ ・ ・ △

88 UA- 118 Dacite 413086 2053638 △ △ ・

89 UA- 124 Andesite 412784 2056441 ○ △ △ ・ ○ ・

90 UA- 125 Dacite 413102 2056158 ○ △ △ △

91 UA- 133 Lapilli tuff 410015 2056579 ○ △ ○ ・ ・ △

92 UA- 134 Tuff 411513 2053491 ◎ ・ ・ △

93 UA- 135 Tuff 412660 2054940 ○ △ ○ ・ △

94 UA- 136 Lapilli tuff 412765 2054690 ○ ◎ ・ △

95 UA- 110601 Tuff 410075 2057525 ◎ ○ ・

96 UA- 111202 Tuff 413940 2054200 ○ ・ △

97 Santiago SE Dacite 408875 2052975 △ △ △ ・ ○

98 FA- 10/17(2) Dacite 408920 2052905 ○ ・ ○ △ △

99 AR-2 Dacite 410311 2052948 ◎ ・ ・

100 AR-5 Tuff 410255 2053126 △ ・ △ △

101 AR-10 ore 411793 2054039 △ ・ ○ ○ ◎

102 AR-11 ore 410625 2054605 ・ ・ △ ◎

Legend; ◎,abundant; ○, common; △, minor; ・rare

Qz:quartz, Ab:albite, Kf:K feldspar, Sm:smectite, Ha:halloysite, K: kaolinite, Ch:chlorite, S;sericite,S3;sericite(3T), Pg:palagonite, Gp:gypsum,

Ba:barite, Ja:jarosite, Ca:calcite, Do: dolomite, Py:pyrite, Gn:galena, Sph:sphalerite, Px:pyroxene, Hb:horblende, Ep:epidote

Coordinates

UTM-E UTM-N

Table Ⅱ－１－３ Result of X-ray diffraction(3)

Other MineralsRemarks

Detected Minerals

Silica M Feldspar M Clay Minerals Sulphate MSample No, Rock nametype

No.

Table Ⅱ－１－4(1) Result of fluid inclusion test(temperature)

Temperature（℃）range average S.D. UTM-E UTM-N

1 GL-A Quartz 20 144～163 153.2 4.2 Size＝7.5～25.0μm 413630 20548702 YB-2 Quartz 20 241～325 292.0 20.6 Size＝7.5～60.0μm 413500 20564803 JA-88 Quartz 20 162～235 198.4 19.0 Size＝5.0～25.0μm 410783 20527224 J100701 Quartz 20 194～261 232.6 17.8 Size＝5.0～12.5μm 405493 20579635 FA0-1 Quartz 20 196～248 229.5 13.1 Size＝2.5～27.5μm 408443 20572286 Mt R　　　　 Quartz 20 165～222 197.8 16.7 Size＝5.0～37.5μm 408500 20573807 Capire Quartz 20 169～233 206.6 17.2 Size＝5.0～32.5μm 410625 20546158 FA0-2 Calcite 20 143～188 172.2 10.8 Size＝5.0～32.5μm 408425 20578959 C Campana Quartz 20 212～235 223.0 5.9 Size＝5.0～32.5μm 407081 205814710 FA1024(1) Quartz 20 162～196 180.1 8.4 Size＝2.5～17.5μm 412131 205344811 FR0-1 Calcite 20 215～242 229.3 7.6 Size＝5.0～17.5μm 409970 204387512 JR-38 Calcite 20 163～231 194.2 17.2 Size＝5.0～12.5μm 409458 204573213 Au-Ⅱ(AR10) Quartz 20 173～251 217.2 23.0 Size＝5.0～17.5μm 411793 205403914 FA-3 Quartz 20 155～216 183.9 16.4 Size＝7.5～25.0μm 410500 205472015 Santiago SE Quartz 20 125～189 164.3 16.3 Size＝5.0～12.5μm 408875 205297516 Santiago NW Quartz 20 205～274 244.9 16.6 Size＝5.0～12.5μm 408039 205391617 FA-1021 Quartz 20 160～203 178.0 11.2 Size＝5.0～22.5μm 410983 2055021

Table Ⅱ－１－4(2) Result of fluid inclusion test(salinity)

Frozn temp（℃） salinity(wt%)Min. Max. Ave. Min. Max. Ave.

1 GL-A Quartz 16 -2.5 -1.9 -2.14 3.23 4.18 3.612 YB-2 Quartz 19 -0.2 0 -0.12 0 0.35 0.213 JA-88 Quartz 15 -1.5 -1.0 -1.18 1.74 2.24 2.044 J100701 Quartz 15 -1.7 -0.8 -1.18 1.40 2.74 2.045 FA0-1 Quartz 14 -2.6 -1.9 -2.31 3.23 4.49 3.896 Mt R　　　　 Quartz 16 -2.2 -1.7 -1.95 2.90 3.55 3.317 Capire Quartz 16 -1.6 -0.9 -1.25 1.57 3.39 2.168 FA0-2 Calcite 14 -6.2 -4.7 -5.22 7.45 9.47 8.179 C Campana Quartz 17 -2.5 -2.1 -2.34 3.55 4.18 3.9310 FA1024(1) Quartz 11 -1.4 -0.8 -1.02 1.23 2.41 1.7711 FA0-1 Calcite 15 -1.7 -1.4 -1.65 2.41 2.90 2.8112 JR-38 Calcite 14 -1.4 -0.9 -1.19 1.57 2.41 2.0613 Au-Ⅱ Quartz 12 -0.6 -0.2 -0.41 0.35 0.88 0.7114 FA-3 Quartz 18 -2.6 -1.7 -2.33 2.90 4.65 3.9115 Santiago SE Quartz 12 -3.5 -1.3 -2.78 2.24 5.71 4.5916 Santiago NW Quartz 11 -2.3 -1.6 -2.03 2.74 3.87 3.4317 FA-1021 Quartz 16 -3.1 -2.3 -2.66 3.87 5.11 4.43

Ｃｏｏｒｄｉｎａｔeｓ

Number

Sample name mineral Form

Remarks

No.

No. Sample name mineral

inclusion no.

FA-10/28 slate no carb 16.6 413208 2054807FA-11/8-10 dacitic tuff no carb 20.2 408165 2053395FA-11 dacite no carb 16.2 408365 2057590FA-12 andesitic tuff treated 20% HCl 14.9 408474 2057947FA-34 dacitic tuff treated 20% HCl 20.0 408884 2052946FA-35 slate treated 20% HCl 20.6 408930 2052844FA-36 dacite treated 20% HCl 21.0 409069 2052502FA-51 dacitic tuff treated 20% HCl 18.5 412180 2053225FA-52 dacitic tuff treated 20% HCl 17.0 412112 2053550FA-54 dacitic tuff treated 20% HCl 10.7 412070 2054145FA-55 dacite no carb 10.3 412061 2054335FA-56 dacitic tuff no carb 11.2 412260 2053895FA-60 dacite no carb 16.6 413115 2054789FA-80 andesite treated 20% HCl 12.4 408230 2056700FA-84 dacite treated 20% HCl 16.8 408370 2057360FA-85 slate treated 20% HCl 16.3 408380 2057370JA-49 andesitic tuff treated 20% HCl 12.2 408945 2054690JA-122 andesite breccia no carb 15.9 414080 2054440JA-123 andesite breccia no carb 15.8 414345 2054490JA-144 andesite treated 20% HCl 12.7 409740 2054430NA-33 dacitic tuff treated 20% HCl 14.5 410225 2056270UA-66 andesite no carb 13.0 410963 2053886UA-67 andesite no carb 13.2 409644 2055876UA-69 dacite no carb 15.8 410056 2056135UA-71 andesite no carb 12.7 410303 2056189UA-73 tuff treated 20% HCl 14.9 410978 2056273UA-74 andesite treated 20% HCl 11.3 410985 2054159UA-76 andesite treated 20% HCl 11.6 411214 2054655UA-78 andesite no carb 10.1 411538 2054741UA-106 sandy tuff no carb 15.4 413686 2054082UA-113 dacitic tuff no carb 15.8 411743 2053843

Sample No Type δ13C δ18O UTM-E UTM-NJA-58 Limestone -12.4 -9.7 408495 2053305JA-74 Limestone -1.6 -7.2 408165 2052405UA-72 Limestone 1.0 -9.5 410733 2056276JA-145 Limestone -4.6 -13.1 410390 2054125JA-124 Limestone 1.7 -8.0 414540 2054610UA-103 Limestone 0.7 -12.0 413795 2053752

Table Ⅱ－１－５ Result of isotope analysis(δ18O and δ13C)

UTM-N

δ13C　and δ18O on Carbonates

δ18O on Silicates

Sample No Type Treated for Carbonate δ18O(SMOW)

UTM-E

－97－

Chapter 2 Geochemical Survey

2-1 Survey Method

The rock geochemical survey has been performed in the Rancho Viejo and

Aurora areas. The samples have been taken in the spacing of about every five samples

per one kilometer along the survey lines, but more dense in the ore horizon and

mineralized zones. Only fresh parts of rocks have been taken, eliminating weathered

part. The duplicate sampling for every 20 points has been performed to check assay

accuracy.

All samples have been assayed for the major oxides and minor elements. The

duplicated samples have been assayed for only the minor elements. The assay has been

asked for ALS Chemex. The assay method and detection limits are shown in the

following table. Element Method detection

limit Element Method detection

limit Al203 XRF 0.01% BaO XRF 0.01% CaO XRF 0.01% Cr2O3 XRF 0.01% Fe2O3 XRF 0.01% K2O XRF 0.01% MgO XRF 0.01% MnO XRF 0.01% Na2O XRF 0.01% P2O5 XRF 0.01% SiO2 XRF 0.01% SrO XRF 0.01% TiO2 XRF 0.01% LOI XRF 0.01% Au FA-ICP 1ppb Ag ICP-AES 0.2ppm Al ICP-AES 0.01% As ICP-AES 2ppm B ICP-AES 10ppm Ba ICP-AES 10ppm Be ICP-AES 0.5ppm Bi ICP-AES 2ppm Ca ICP-AES 0.01% Cd ICP-AES 0.5ppm Co ICP-AES 1ppm Cr ICP-AES 1ppm Cu ICP-AES 1ppm Fe ICP-AES 0.01% Ga ICP-AES 10ppm Hg ICP-AES 1ppm K ICP-AES 0.01% La ICP-AES 10ppm Mg ICP-AES 0.01% Mn ICP-AES 5ppm Mo ICP-AES 1ppm Na ICP-AES 0.01% Ni ICP-AES 1ppm P ICP-AES 10ppm Pb ICP-AES 2ppm S ICP-AES 0.01% Sb ICP-AES 2ppm Sc ICP-AES 1ppm Sr ICP-AES 1ppm Ti ICP-AES 0.01% Tl ICP-AES 10ppm U ICP-AES 10ppm V ICP-AES 1ppm W ICP-AES 10pm Zn ICP-AES 2ppm

－98－

2-2 Survey Result

Table II-2-1 shows the chemical assay result.

1 Major Oxides

Figures II-2-1, II-2-2, and II-2-3 show the histogram, scatter diagram, and

distribution map of alteration index. The rocks assayed are mainly andesitic to basaltic

volcanic rocks, dacitic volcanic rocks, and sedimentary rocks, and the obtained assay

values reflect these rock facies.

The alteration index (MgO+K2O)/(Na2O+CaO+MgO+K2O)X100% has been

calculated and investigated to extract alteration zones associated with mineralization,

because the reaching of Na and Ca, and addition of Mg and K are some characteristics

of the common massive sulphide type alteration.

The interpretation has been done for separated rock facies such as the

andesite of the Villa Ayala Formation, dacite of the same formation, sedimentary rocks

of the Villa Ayala and Pachivia Formations, and andesite of the Pachivia Formation.

In the histogram, it tends to that the dacite shows higher background value

than that of the andesite. The background value of the sedimentary rocks shows a

dispersed distribution due to their wide range of rock facies from calcareous to

tuffaceous. Judging from the histogram of each rock facies, the anomaly value is set up

as +1σ in average, and further detailed ranking is set up.

Anomaly zones occupying some portions in the Aurora area are Capire deposit

to the north of Aurora I deposit and an area between the south of Aurora II deposit and

Guadalupe deposit. Small size anomalies are dispersed around Santiago Salinas and

south of Velixtla. An anomaly to the southwest of La Campana is of one point, but its

value is above +2σ, even though the sampling space there is wide. It is thought that

an anomaly zone on a ridge to the southwest of MJZC-3 would be affected by

weathering.

In the Rancho Viejo area, an anomaly zone occupying some area is situated to

the northwest of Tierra Colorada, and this is correlated to the place where some

altered rocks dominated in the sedimentary and pyroclastic rocks.

－99－

2 Minor Elements

The assay result has been processed by logarithmic transformation for every

component, and interpreted. The values lower than the detection limit have been

calculated being regarded as the half of the limit value. Figure II-2-4 to Figure II-2-17

show the interpretation result. The histograms of main elements have been made for

the four categories of the rock facies same as the case of the whole rock analysis. No

value for W and Tl exists in the result. Followings are the description of the

distribution patterns of elements for each group.

(1) B, Hg, U

More than 95 percent of the specimens have the values of less than the

detection limit. It is possible that B and Hg are associated with the local alteration and

fracture. U has been detected mainly in the sedimentary rocks.

(2) Be, Bi, Ga, La

Seventy to eighty percent of these elements show the value of less than the

detection limit. Be and Bi are detected sporadically, but are more frequently appear in

the Rancho Viejo area. Ga is not detected in the western part of the Aurora area and

the eastern part of the Rancho Viejo area. La tends to be detected in the dacite. No

relation is recognized between those elements and mineralization.

(3) Ag, Au, Cd, Mo, Sb

Seventy to eighty per cent of these elements show the values of less than the

detection limit. It is probable that the slightly higher values reflect some hydrothermal

activity or mineralization.

Ag is contained in both vein-type and massive sulphide type deposits. Ag

shows the highest value of 20 ppm in La Campana West, and 18 ppm near by

Guadalupe. Other anomalies over 1 ppm exist in the following portions to the

southwest of the Manto Rico deposit, near by San Carlos, near by the Capire deposit,

and to the southeast of the Aurora deposit. The San Carlos deposit is of the vein-type,

－100－

but the other anomalies supposedly reflect the massive sulphide type mineralization.

The background value of Ag is high in the Rancho Viejo area, but only one point shows

1 ppm.

Au is positively correlated with Ag, and its anomalies coincident with that of

Ag in many cases. Au is not detected vicinity areas of the vein-type San Carlos deposit,

therefore it is thought that many of Au anomalies probably reflect the massive

sulphide type mineralization. Au shows 84 ppb in an area to the west of Capire, 83 ppb

to the west of La Campana, and over 10 ppb in Santiago Salinas and Aurora II deposit.

Cd is commonly contained in sphalerite, and it behaves with Zn. A north to

south extending remarkable anomaly zone exists near by the vein-type San Carlos

deposit. Other high anomaly zones are in areas to the south-southwest of the Manto

Rico deposit, near by the Capire deposit, Aurora II deposit, and near by Guadalupe

deposit to Cruz Blanca deposit.

Mo tends to higher in the dacite and sedimentary rocks. It only shows slightly

high values in the known massive sulphide type mineral occurrences, and no strong

relation with mineralization is recognized.

Sb anomalies are concentrated in the areas to the south of Velixtla in the

northern to northwestern district, to the southwest of the Manto Rico deposit, and to

the west of La Campana. In the vein-type San Carlos deposit, Sb shows below the

detection limit value. Only weak anomalies have been detected near by the known

massive sulphide type mineral occurrences. It is well known that the ores of the Capire

and Aurora deposits contain tetrahedrite, (Cu,Fe)12Sb4S13, and miargyrite, AgSbS2,

therefore it is possible that Sb reflects the massive sulphide type mineralization.

However, it is not clear that the all Sb anomalies in the northern to northwestern

district indicate existence of massive sulphide mineralization.

(4) Co, Cr, Mn, Ni, P, Sc, Sr, V

The density distribution-pattern of the elements reflects the rock facies. These

elements such as Co, Cr, Ni, Sc, V tend to show high values in the andesitic volcanic

rocks. Mn and P tend to show high values in the sedimentary rocks. No direct relation

－101－

between these elements and mineralization.

(5) As, Ba, Cu, Pb, Zn, S

It is highly possible that these elements reflect the vein-type and massive

sulphide type mineralization.

Around a half of the whole samples show the value below the detection limit (2

ppm for As). In the histograms, some groups showing over 3.5 ppm exist in every rock

facies, indicating somewhat anomalous zones. The background value of the dacite and

sedimentary rocks having over 3.5 ppm anomalous groups is slightly higher than that

of the andesite. In the Aurora area, if the average values +1σare set for anomaly, some

anomaly areas are recognized in areas to the south of Velixtla, to the south of the

Manto Rico deposit, near by Tlanilpa occurrence, near by Capire deposit, to the south

of Aurora II deposit, and around Santiago Salinas. Some sporadic anomalies are in

areas to the northwest of the Yerba Buena deposit, to the west of La Campana, and in

the western end of the district. In the Rancho Viejo area, some anomalous area exists

around Terra Colorada.

Massive sulfide ores in the Aurora area have relatively high content of Ba.

This survey has clearly revealed that the ores of the Yerba Buena deposit contain low

Ba (9 ppm). The dacite shows generally higher value than that of the andesite. Some

anomalous zones showing +1σ are extracted in areas from the Capire deposit to

Guadalupe deposit and to the south. Slightly anomalous zones exist areas from the

north of the Manto Rico deposit to the west of Campana, to the west of Santiago

Salinas, and around El Copal. In the Rancho Viejo, some sporadic anomalies tend to

distribute in the central part extending north to south.

Cu shows significant different values for different rock facies. One population

showing the normal distribution exists in the Villa Ayala Formation and Pachivia

Formation respectively, but the latter shows rather higher value than that of the

former. It is judged that the dacite and sedimentary rocks are conformed by multi

numbers of populations, but its variation is large. In the Aurora area, anomalous zones

showing +1σ for each rock facies exist in areas from the Capire deposit to the east of

－102－

the Aurora II deposit, and from the Guadalupe deposit to Cruz Blanca deposit. In the

Rancho Viejo area, the anomalies tend to distribute from the central to the northern

parts.

Pb shows multiple numbers of populations in the histogram. The andesite has

same tendency in the Villa Ayala and Pachivia Formations, Pb is clustered in the lower

side. The dacite shows higher Pb values than that of in the andesite, and has two peaks

in the histogram. The sedimentary rocks show the similar tendency with that of the

dacite. In the Aurora area, the distributions of the average values +1σ are seen in the

areas from the San Carlos deposit to the south of Velixtla, around the Tlanilpa

occurrence, the Guadalupe deposit and to the west, and to the north of Azulaquez. The

small-scale distributions are seen in the Capire deposit and Aurora I deposit. It is

possible that the anomaly distributed from the San Carlos deposit to the south of

Velixtla reflects vein-type mineralization. In the Rancho Viejo area, there are some

sporadic distributions of weak anomaly.

Zn shows one population of the normal distribution in the andesitic rocks, and

the Villa Ayala and Pachivia Formations show the same tendency. It appears that Zn

values of the dacite are almost in one population, but there exist some clearly high

values. The Zn values of the dacite tend to lower than that of the andesitic rocks. The

Zn values of the sedimentary rocks are scattered, but two populations are recognized.

The anomalous zones showing +1σ in average are areas from the San Carlos deposit

to the south of Velixtla, from the Capire deposit to the east of the Aurora I deposit, and

from the Guadalupe deposit to the Cruz Blanca deposit. The anomaly around the San

Carlos reflects vein-type mineralization. In the Rancho Viejo area, small anomalies are

scattered.

S is well reflective for existence of mineralized zones, and can be applied as

same as alteration. In the histogram, several populations are supposedly recognized. It

is possible that the population of the highest values reflects mineralized zones. About

over 0.322 percent of the values are regarded as anomalous values for every rock facies,

and this is correlated to the value of +1σ. In the Aurora area, the anomaly zones are in

areas to the south of Velixtla, to the south of the Manto Rico deposit, from Tlanilpa to

－103－

the Aurora deposit, to the southeast of MJZC-3, and to the southeast of the Aurora II

deposit. Other sporadic anomaly zones are in the western end district, around Otates,

around Santiago Salinas, in the Guadalupe deposit, and around Azulaquez. In the

Rancho Viejo area, some sporadic anomalies exist around Tierra Colorada and to the

north and south of Rancho Viejo Village.

(6) Principal Component Analysis

The principal component analysis has been performed to judge in an

integrated manner the behavior of the elements associated with mineralization. The

elements strongly reflected rock facies characteristics are eliminated. Table II-2-4 and

Figure II-2-18 show the result of analysis.

The first factor shows high load of Co, Cu, Ni, Sc, and V, reflecting the

andesite facies. The contribution rate is 25.5 percent.

The second factor shoes high minus load of As and Pb, and followed by Au, Ag,

Mo, S, Sb, etc. It is, therefore, judged that these elements are the good integral

indicators for mineralized zones. The contribution rate is 11.9 percent.

In the Aurora area, those zones concentrated by the high-points, average +1σ,

in “Figure II-2-18 the points distribution of the second factor” are La Campana, the

south of Velixtla, the southwest of the Manto Rico deposit, San Carlos deposit, Capire

deposit to Aurora I deposit, the southeast of the Aurora II deposit, and the southwest of

Santiago Salinas to the southeast. In the Guadalupe and Cruz Blanca deposits, only

one point shows high +2σ value.

It is possible that the anomaly zones present both vein-type and massive

sulphide type mineralized zones. It is possible that the anomalies to the south of

Velixtla and near by the San Carlos are of the vein-type, and others of the massive

sulphide type.

In the Rancho Viejo area, some sporadic anomalies are scattered in the

northwestern part.

(7) Geochemical Anomaly

－104－

From the above-mentioned result, some geochemical anomaly areas have been

extracted based on the alteration index, principal component, and density distribution

of S. Figure II-2-19 shows the distribution of anomaly areas.

The anomaly areas are distributed in areas from around the Capire deposit to

the southeast of the Aurora II deposit and near by the Guadalupe deposit in large area,

and in areas to the south of Velixtla, to the west of La Campana, to the south of the

Manto Rico deposit, near by Tlanilpa occurrence, and Santiago Salinas in slightly

small-scale.

In areas near by the vein-type Yerba Buena and San Carlos deposits, no

anomaly is recognized nor indicating small-scale.

(8) Spectral Analysis

The spectral-reflection spectrum has been obtained. The spectrometer

“POSAM: Portable SpectrorAdiometer for Mineral identification” made by Dowa

Engineering Co.” has been used. The wavelength between 1,300 and 2,500 millimeters

has been measured. Figure II-2-20 shows the spectral-chart of the measurement. The

measured figures are of the specimen’s relative reflectivity for barite white board in

the range of the wavelength.

The altered minerals identified by the spectral data are sericite,

montmorillonite, illite, chlorite, epidote, and calcite. The identification has been done

through the judgment of existence by the absorption strength, estimation of volume by

the depth of the absorption peaks, and presentation in numerical figures. The

sericite/chlorite ratio and the change of absorption peak positions have been

investigated as an application trial for the alteration zoning from the spectrometric

analysis, and the spectral analysis result is shown in Table II-2-5 and Figure II-2-21.

As shown in Figure II-2-21, the identified mineral distribution is shown as bar

graphs being in proportion to the apparent mineral volume, i.e. absorption strength, at

their sampling positions. Each mineral is presented by different graphical axis. The

change of the absorption peaks for sericite and montmorillonite is expressed by red in

case of shifting to the long-wave-length side, and by blue incase of shifting to the short

－105－

wave length side. The sericite/chlorite ratio is changed to numerical figures by the

formula “sericite - chlorite / sericite + chlorite” setting +1 for sericite and -1 for chlorite.

Figure II-2-21 shows much chlorite in the andesite dominant areas, and much sericite

in the dacite dominant areas. Some relations between rock types and identified

minerals by the spectral analysis are recognized. The sericite/chlorite ratio is also

related with rock types, the ratio is high in dacite and low in andesite.

The absorption position of the spectrum of the sericite in Yerba Buena and

San Carlos deposits, Velixtla, and Otates NW occurrences shifted to the

short-wave-length side, and that in the massive sulfide type Guadalupe, Curz Blanca,

Aurora I, and Aurora II deposits shifted mainly to the long wavelength side. It

probably indicates that same sericite identified by the spectral analysis can be

classified into two different types, vein-type or massive sulphide type, depending upon

their wavelength shift pattern.

Fig.Ⅱ－２－１　Scatter diagram of major elements

Number Average Exponential ave. Standard deviationAll Sample

439 37.6 - 21.6Villa Ayala Formation Andesite

158 35.0 - 14.6Villa Ayala Formation Dacite

137 49.4 - 20.9Sedimentary rocks(Villa Ayala F. + Pachivia F.)

101 27.4 - 27.3Pachivia Formation Andesite

42 33.5 - 12.4

All Sample

0

20

40

60

80

100

0.0

1.5

8.7

16.0

23.2

30.4

37.6

44.8

52.0

59.2

66.4

73.7

80.9

88.1

95.3

100.0

Alteration Index

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Villa Ayala Formation Andesite

0102030405060

0.0

1.5

8.7

16.0

23.2

30.4

37.6

44.8

52.0

59.2

66.4

73.7

80.9

88.1

95.3

100.0

Alteration Index

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Villa Ayala Formation Dacite

0

5

10

15

20

0.0

1.5

8.7

16.0

23.2

30.4

37.6

44.8

52.0

59.2

66.4

73.7

80.9

88.1

95.3

100.0

Alteration Index

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Sedimentary rocks(Villa Ayala F. + Pachivia F.)

05

1015202530

0.0

1.5

8.7

16.0

23.2

30.4

37.6

44.8

52.0

59.2

66.4

73.7

80.9

88.1

95.3

100.0

Alteration Index

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Pachivia Formation Andesite

0

5

10

15

20

0.0

1.5

8.7

16.0

23.2

30.4

37.6

44.8

52.0

59.2

66.4

73.7

80.9

88.1

95.3

100.0

Alteration Index

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Fig. Ⅱ－２－２　Histogram of alteration index

Fig.Ⅱ－２－３　Distribution map of alteration index

Fig.Ⅱ－２－４　Scatter diagram of minor elements

Number Average Exponential ave. Standard deviationAll Sample

439 5.44 2.43 2.96Villa Ayala Formation Andesite

158 4.28 2.19 2.86Villa Ayala Formation Dacite

137 5.75 2.81 3.01Sedimentary rocks(Villa Ayala F. + Pachivia F.)

101 8.32 2.86 3.31Pachivia Formation Andesite

42 1.95 1.53 1.88

All Sample

0

50

100

150

200

250

1.2

1.7

2.4

3.5

5.0

7.2 10

15

21

31

44

63

91

130

187

268

As

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Villa Ayala Formation Andesite

0

20

40

60

80

100

1.2

1.7

2.4

3.5

5.0

7.2 10

15

21

31

44

63

91

130

187

268As

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Villa Ayala Formation Dacite

0102030405060

1.2

1.7

2.4

3.5

5.0

7.2 10

15

21

31

44

63

91

130

187

268

As

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Sedimentary rocks(Villa Ayala F. + Pachivia F.)

0

10

20

30

40

50

1.2

1.7

2.4

3.5

5.0

7.2 10

15

21

31

44

63

91

130

187

268

As

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Pachivia Formation Andesite

05

1015202530

1.2

1.7

2.4

3.5

5.0

7.2 10

15

21

31

44

63

91

130

187

268

As

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Fig. Ⅱ－２－５　Histogram of As

Fig.Ⅱ－２－６Distribution map of Aｓ

Number Average Exponential ave. Standard deviationAll Sample

439 50.7 29.0 2.8Villa Ayala Formation Andesite

158 44.3 27.5 2.6Villa Ayala Formation Dacite

137 73.6 44.7 2.6Sedimentary rocks(Villa Ayala F. + Pachivia F.)

101 24.1 15.6 2.5Pachivia Formation Andesite

42 64.2 38.1 2.6

All Sample

0

50

100

150

200

5.3

7.5 11

15

21

29

41

57

80

112

157

220

309

433

607

852

Ba

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Villa Ayala Formation Andesite

0102030405060

5.3

7.5 11

15

21

29

41

57

80

112

157

220

309

433

607

852

Ba

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Villa Ayala Formation Dacite

0102030405060

5.3

7.5 11

15

21

29

41

57

80

112

157

220

309

433

607

852

Ba

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Sedimentary rocks(Villa Ayala F. + Pachivia F.)

05

1015202530

5.3

7.5 11

15

21

29

41

57

80

112

157

220

309

433

607

852

Ba

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Pachivia Formation Andesite

05

1015202530

5.3

7.5 11

15

21

29

41

57

80

112

157

220

309

433

607

852

Ba

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Fig. Ⅱ－２－７　Histogram of Ba

Fig.Ⅱ－２－８Distribution map of Ba

Number Average Exponential ave. Standard deviationAll Sample

439 23.7 10.6 3.9Villa Ayala Formation Andesite

158 22.3 16.2 2.6Villa Ayala Formation Dacite

137 12.6 5.1 3.3Sedimentary rocks(Villa Ayala F. + Pachivia F.)

101 31.4 8.4 5.2Pachivia Formation Andesite

42 47.6 43.0 1.6

All Sample

0102030405060

0.7

1.0

1.4

1.9

2.7

3.8

5.3

7.5 11

15

21

30

42

59

83

117

164

231

326

Cu

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/4σ

Villa Ayala Formation Andesite

0

10

20

30

40

0.7

1.0

1.4

1.9

2.7

3.8

5.3

7.5 11

15

21

30

42

59

83

117

164

231

326

Cu

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/4σ

Villa Ayala Formation Dacite

0

5

10

15

20

25

0.7

1.0

1.4

1.9

2.7

3.8

5.3

7.5 11

15

21

30

42

59

83

117

164

231

326

Cu

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/4σ

Sedimentary rocks(Villa Ayala F. + Pachivia F.)

02468

101214

0.7

1.0

1.4

1.9

2.7

3.8

5.3

7.5 11

15

21

30

42

59

83

117

164

231

326

Cu

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/4σ

Pachivia Formation Andesite

0

5

10

15

20

0.7

1.0

1.4

1.9

2.7

3.8

5.3

7.5 11

15

21

30

42

59

83

117

164

231

326

Cu

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/4σ

Fig. Ⅱ－２－９　Histogram of Cu

Fig.Ⅱ－２－１０Distribution map of Cu

Number Average Exponential ave. Standard deviationAll Sample

439 11.1 4.1 2.9Villa Ayala Formation Andesite

158 5.3 2.9 2.6Villa Ayala Formation Dacite

137 8.8 6.0 2.4Sedimentary rocks(Villa Ayala F. + Pachivia F.)

101 23.8 4.3 3.7Pachivia Formation Andesite

42 10.0 3.3 3.1

All Sample

020406080

100120

1.4

2.4

4.1

6.9 12

20

35

59

102

174

298

509

871

1491

Pb

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/2σ

Villa Ayala Formation Andesite

0102030405060

1.4

2.4

4.1

6.9 12

20

35

59

102

174

298

509

871

1491

Pb

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/2σ

Villa Ayala Formation Dacite

0

10

20

30

40

50

1.4

2.4

4.1

6.9 12

20

35

59

102

174

298

509

871

1491

Pb

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/2σ

Sedimentary rocks(Villa Ayala F. + Pachivia F.)

0

5

10

15

20

25

1.4

2.4

4.1

6.9 12

20

35

59

102

174

298

509

871

1491

Pb

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/2σ

Pachivia Formation Andesite

02468

101214

1.4

2.4

4.1

6.9 12

20

35

59

102

174

298

509

871

1491

Pb

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/2σ

Fig. Ⅱ－２－１１　Histogram of Pb

Fig.Ⅱ－２－１２Distribution map of Pb

Number Average Exponential ave. Standard deviationAll Sample

439 99.1 53.7 2.7Villa Ayala Formation Andesite

158 78.5 71.1 1.6Villa Ayala Formation Dacite

137 83.8 58.0 2.2Sedimentary rocks(Villa Ayala F. + Pachivia F.)

101 163.0 28.3 5.1Pachivia Formation Andesite

42 72.9 67.1 1.5

All Sample

0

50

100

150

200

1.6

2.6

4.4

7.2 12

20

33

54

89

147

243

401

662

1095

Zn

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/2σ

Villa Ayala Formation Andesite

0

20

40

60

80

100

1.6

2.6

4.4

7.2 12

20

33

54

89

147

243

401

662

1095Zn

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/2σ

Villa Ayala Formation Dacite

0102030405060

1.6

2.6

4.4

7.2 12

20

33

54

89

147

243

401

662

1095

Zn

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/2σ

Sedimentary rocks(Villa Ayala F. + Pachivia F.)

0

5

10

15

20

1.6

2.6

4.4

7.2 12

20

33

54

89

147

243

401

662

1095

Zn

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/2σ

Pachivia Formation Andesite

05

1015202530

1.6

2.6

4.4

7.2 12

20

33

54

89

147

243

401

662

1095

Zn

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/2σ

Fig. Ⅱ－２－１３　Histogram of Zn

Fig.Ⅱ－２－１４Distribution map of Zn

Number Average Exponential ave. Standard deviationAll Sample

439 0.2507 0.0523 6.1633Villa Ayala Formation Andesite

158 0.2353 0.0406 6.8851Villa Ayala Formation Dacite

137 0.1838 0.0490 5.7246Sedimentary rocks(Villa Ayala F. + Pachivia F.)

101 0.4081 0.0933 5.8982Pachivia Formation Andesite

42 0.1533 0.0418 4.3407

All Sample

0

20

40

60

80

100

0.0

08

0.0

16

0.0

29

0.0

52

0.0

96

0.1

76

0.3

22

0.5

90

1.0

8

1.9

8

3.6

4

6.6

7

S

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Villa Ayala Formation Andesite

0

10

20

30

40

50

0.0

08

0.0

16

0.0

29

0.0

52

0.0

96

0.1

76

0.3

22

0.5

90

1.0

8

1.9

8

3.6

4

6.6

7S

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Villa Ayala Formation Dacite

05

101520253035

0.0

08

0.0

16

0.0

29

0.0

52

0.0

96

0.1

76

0.3

22

0.5

90

1.0

8

1.9

8

3.6

4

6.6

7

S

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Sedimentary rocks(Villa Ayala F. + Pachivia F.)

05

1015202530

0.0

08

0.0

16

0.0

29

0.0

52

0.0

96

0.1

76

0.3

22

0.5

90

1.0

8

1.9

8

3.6

4

6.6

7

S

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Pachivia Formation Andesite

02468

1012

0.0

08

0.0

16

0.0

29

0.0

52

0.0

96

0.1

76

0.3

22

0.5

90

1.0

8

1.9

8

3.6

4

6.6

7

S

Freq

uenc

y

0%

20%

40%

60%

80%

100%

間隔=1/3σ

Fig. Ⅱ－２－１５　Histogram of S

Fig.Ⅱ－２－１６Distribution map of S

Fig.Ⅱ－２－１８Distribution map of principal factor 2

Alteration Index (>M+1 )

S (>M+1 )

PC2 (<M 1 )

Fig.Ⅱ－２－１９　Distribution map of geochemical anomaly zones

TotalOH

Sericitered : + shift blue :

Epidote

Calcite

Chlorite

Illite + Montmorillonitered : + shiftblue :

(Sericite Chlorite)(Sericite + Chlorite)

Fig.Ⅱ－２－２１　Result of spectral analysis

Table Ⅱ－２－２　List of statistic data for cemical analysis

Element Al2O3 BaO CaO Cr2O3 Fe2O3 K2O MgO MnO Na2O P2O5 SiO2 SrO TiO2 LOIMinmum 0.07 0.005 0.03 0.005 0.06 0.01 0.005 0.005 0.005 0.005 0.55 0.005 0.005 1.4Maximum 20.45 0.71 54.7 0.13 12.67 10.12 14.1 0.55 7.34 2.35 91.83 0.15 2 44.74Average 13.02558 0.054214 9.298519 0.010273 4.810456 1.543599 2.868394 0.077916 2.533781 0.135 54.8441 0.031333 0.57672 9.532984Geometoric meanMedian 14.41 0.04 5.16 0.005 5.08 1.27 2.56 0.06 2.56 0.1 57.01 0.03 0.67 5.43Standard deviation 4.838566 0.063824 13.4907 0.012657 2.643082 1.350471 1.989914 0.073046 1.671853 0.202828 19.228 0.023639 0.375587 10.75988Detection limit

Element Au Ag Al As B Ba Be Bi Ca Cd Co Cr Cu FeMinmum 0.5 0.1 0.01 1 5 5 0.25 1 0.005 0.25 0.5 1 0.5 0.04Maximum 84 20 5.35 200 20 670 1.5 8 15 56 40 299 1135 7.79Average 1.318907 0.257403 1.837084 5.439636 5.125285 50.67198 0.33713 1.302961 3.761993 0.583144 9.849658 47.67198 23.74943 2.716446Geometoric mean 0.654788 0.135292 1.211064 2.428791 5.079573 28.98291 0.309072 1.147112 1.512547 0.334518 4.973959 33.38624 10.60745 2.001183Median 0.5 0.1 1.82 2 5 30 0.25 1 1.94 0.25 10 38 14 2.86Standard deviation 5.87539 1.306773 1.15288 13.42935 0.97703 76.26972 0.182604 1.092425 4.670499 2.757189 8.32969 43.48848 60.23678 1.557492Detection limit 358 316 3 210 430 39 320 380 1 328 88 0 18 0

Element Ga Hg K La Mg Mn Mo Na Ni P Pb S Sb ScMinmum 5 0.5 0.005 5 0.005 2.5 0.5 0.005 0.5 5 1 0.005 1 0.5Maximum 20 4 1.71 30 7.8 2920 121 0.11 386 9790 1260 6.08 20 24Average 6.492027 0.531891 0.087016 6.127563 1.385547 489.664 1.58656 0.022232 15.20501 539.8747 11.07289 0.250683 1.457859 5.405467Geometoric mean 6.129536 0.516518 0.055857 5.721225 0.929937 319.1341 0.75713 0.016559 5.386598 315.059 4.054689 0.052254 1.175824 3.207174Median 5 0.5 0.07 5 1.22 400 0.5 0.02 6 380 4 0.05 1 4Standard deviation 2.435338 0.231895 0.103369 3.211302 1.02574 417.4205 6.629843 0.017015 29.52702 822.6597 64.75478 0.590845 1.842528 4.752151Detection limit 312 423 34 364 0 0 301 80 62 0 83 94 380 74

Element Sr Ti Tl U V W ZnMinmum 2 0.005 5 5 0.5 5 1Maximum 778 0.49 5 50 320 5 10000Average 79.36674 0.077437 5 6.161731 51.78018 5 99.10478Geometoric mean 36.18366 0.025962 5 5.386678 20.04279 5 53.74252Median 34 0.02 5 5 43 5 64Standard deviation 123.1657 0.091732 0 6.322302 50.05463 0 481.7116Detection limit 0 201 439 419 25 439 0

Table Ⅱ－２－３　Correlation coefficient of minor elements

AU AG AL AS B BA BE BI CA CD CO CR CU FE GA HG K LA MG MN MO NA NI P PB S SB SC SR TI TL U V W ZNAU 1.00 0.29 -0.05 0.30 -0.05 0.01 0.02 0.05 -0.10 0.02 -0.07 0.06 0.05 0.01 -0.08 0.12 0.06 -0.01 -0.07 -0.10 0.19 0.01 -0.02 -0.08 0.25 0.17 0.27 -0.09 -0.09 -0.05 -- -0.02 -0.04 -- -0.03AG 0.59 1.00 0.09 0.22 0.05 0.10 0.03 0.12 -0.21 0.30 0.02 0.06 0.20 0.10 0.02 0.02 0.11 0.02 0.05 -0.03 0.07 -0.06 0.05 -0.01 0.29 0.09 0.16 0.01 -0.22 0.05 -- -0.09 0.04 -- 0.19AL -0.08 0.05 1.00 -0.05 0.11 0.20 0.34 0.12 -0.14 0.16 0.65 0.63 0.54 0.91 0.46 -0.03 0.33 -0.06 0.68 0.33 -0.11 0.39 0.41 0.22 0.07 -0.05 0.01 0.68 -0.35 0.51 -- -0.46 0.56 -- 0.72AS 0.59 0.17 -0.10 1.00 -0.07 0.08 -0.02 -0.04 -0.29 0.10 0.00 0.05 0.05 0.06 -0.11 0.04 0.22 0.11 -0.23 -0.22 0.29 -0.03 -0.01 -0.10 0.43 0.39 0.37 -0.04 -0.28 -0.04 -- 0.00 -0.05 -- 0.06B -0.02 -0.01 0.16 -0.03 1.00 -0.02 0.24 0.00 0.09 0.03 0.10 0.09 0.09 0.07 0.15 -0.02 -0.11 0.00 0.07 0.10 -0.03 0.05 0.15 0.17 -0.03 -0.01 0.01 0.12 0.03 0.16 -- -0.03 0.12 -- 0.06BA 0.23 0.28 -0.10 -0.01 0.00 1.00 -0.01 -0.03 -0.36 -0.04 -0.06 0.17 0.04 0.17 -0.02 -0.04 0.45 0.18 -0.06 -0.09 0.01 0.14 -0.13 -0.22 0.24 -0.05 -0.03 -0.05 -0.31 -0.01 -- -0.20 -0.16 -- 0.27BE -0.02 -0.03 0.38 -0.06 0.23 -0.05 1.00 0.28 0.15 0.17 0.36 0.20 0.31 0.28 0.20 0.06 0.11 -0.02 0.21 0.17 -0.06 0.26 0.31 0.33 -0.02 -0.05 0.03 0.45 0.03 0.55 -- -0.12 0.40 -- 0.18BI -0.02 -0.01 0.12 -0.04 -0.01 -0.06 0.19 1.00 0.11 0.13 0.19 0.12 0.18 0.12 -0.04 0.13 0.04 -0.09 0.14 0.13 -0.01 0.08 0.22 0.24 -0.06 0.02 0.06 0.21 0.04 0.15 -- -0.07 0.20 -- 0.04CA -0.07 -0.07 -0.29 -0.13 0.03 -0.14 -0.06 0.01 1.00 0.16 0.32 -0.14 0.13 -0.12 0.18 0.03 -0.31 -0.25 0.23 0.60 -0.03 -0.02 0.42 0.55 -0.40 0.07 0.02 0.32 0.85 0.24 -- 0.29 0.44 -- -0.18CD 0.00 0.64 0.16 0.03 0.00 0.01 0.00 0.00 -0.01 1.00 0.21 0.17 0.32 0.20 0.15 0.02 0.04 0.01 0.20 0.26 0.07 -0.05 0.33 0.23 0.20 0.09 0.09 0.26 0.11 0.15 -- -0.02 0.27 -- 0.43CO -0.07 0.02 0.69 -0.04 0.08 -0.12 0.27 0.16 -0.04 0.11 1.00 0.51 0.72 0.74 0.44 0.01 0.26 -0.23 0.52 0.64 -0.11 0.38 0.80 0.63 -0.14 0.11 0.09 0.86 0.08 0.65 -- -0.25 0.89 -- 0.46CR 0.00 0.02 0.34 -0.02 0.07 -0.02 0.12 0.15 -0.02 0.07 0.52 1.00 0.47 0.64 0.25 -0.01 0.31 0.02 0.33 0.21 -0.09 0.39 0.53 0.10 0.12 -0.04 0.01 0.50 -0.28 0.42 -- -0.34 0.37 -- 0.50CU 0.00 0.59 0.27 -0.01 0.01 0.00 0.04 0.04 -0.04 0.87 0.30 0.19 1.00 0.61 0.32 0.02 0.29 -0.10 0.39 0.43 -0.03 0.20 0.70 0.46 0.08 0.15 0.06 0.67 -0.04 0.54 -- -0.24 0.66 -- 0.52FE 0.01 0.05 0.83 0.11 0.04 -0.13 0.25 0.15 -0.29 0.14 0.74 0.27 0.28 1.00 0.43 -0.01 0.41 -0.09 0.62 0.41 -0.06 0.40 0.51 0.24 0.12 0.08 0.08 0.72 -0.33 0.47 -- -0.43 0.61 -- 0.74GA -0.06 0.03 0.64 -0.08 0.14 0.00 0.15 -0.06 -0.02 0.08 0.46 0.18 0.15 0.56 1.00 -0.07 -0.07 -0.13 0.43 0.41 -0.11 0.04 0.33 0.27 -0.01 0.00 -0.06 0.49 0.01 0.34 -- -0.13 0.47 -- 0.29HG 0.07 0.00 -0.04 0.05 -0.02 -0.04 0.04 0.04 0.05 -0.01 -0.04 -0.02 -0.01 -0.02 -0.06 1.00 0.00 -0.02 0.02 0.01 0.08 0.07 0.03 0.10 -0.01 0.04 0.16 0.03 0.01 -0.01 -- 0.01 0.07 -- -0.04K 0.09 0.08 -0.05 0.09 -0.04 0.12 0.05 0.00 -0.18 0.01 0.08 -0.03 0.07 0.06 -0.04 -0.02 1.00 0.19 -0.08 0.08 -0.02 0.23 0.12 0.01 0.22 -0.01 0.08 0.23 -0.34 0.11 -- -0.30 0.08 -- 0.41LA 0.03 0.08 -0.15 0.05 -0.01 0.09 -0.01 -0.07 -0.14 0.05 -0.19 -0.05 0.02 -0.16 -0.11 -0.03 0.15 1.00 -0.20 -0.18 0.06 0.02 -0.15 -0.19 0.29 -0.08 -0.05 -0.23 -0.19 -0.18 -- -0.09 -0.31 -- 0.07MG -0.05 0.07 0.73 -0.09 0.05 -0.09 0.20 0.12 -0.06 0.17 0.63 0.47 0.29 0.64 0.48 -0.04 -0.06 -0.14 1.00 0.50 -0.09 0.20 0.44 0.29 -0.14 0.03 -0.05 0.54 0.09 0.37 -- -0.18 0.53 -- 0.47MN -0.09 0.00 0.32 -0.10 0.08 0.01 0.06 0.05 0.30 0.07 0.48 0.28 0.18 0.44 0.40 -0.03 0.08 -0.12 0.34 1.00 -0.12 0.11 0.54 0.54 -0.22 0.06 -0.02 0.57 0.41 0.35 -- -0.04 0.63 -- 0.31MO 0.03 0.00 -0.05 0.10 -0.02 0.01 0.05 -0.01 0.01 0.00 -0.08 -0.07 -0.03 -0.02 -0.05 0.01 -0.02 -0.01 -0.05 -0.03 1.00 -0.12 0.00 0.01 0.19 0.26 0.18 -0.15 -0.01 -0.13 -- 0.08 -0.09 -- -0.04NA -0.04 -0.07 0.17 -0.03 0.04 0.05 0.18 0.08 -0.25 -0.06 0.26 0.14 -0.03 0.21 -0.01 0.06 0.05 0.05 0.08 0.05 -0.05 1.00 0.24 0.20 0.01 -0.05 0.04 0.38 -0.14 0.47 -- -0.24 0.35 -- 0.27NI -0.02 0.06 0.27 -0.05 0.10 -0.03 0.10 0.13 0.22 0.13 0.59 0.69 0.25 0.26 0.20 -0.02 -0.01 -0.05 0.46 0.35 -0.04 0.07 1.00 0.69 -0.11 0.07 0.06 0.69 0.28 0.54 -- -0.06 0.76 -- 0.32P -0.05 0.01 0.00 -0.06 0.14 -0.09 0.14 0.12 0.35 0.06 0.14 -0.02 0.08 -0.01 0.06 0.07 -0.04 -0.04 0.03 0.12 -0.01 0.05 0.15 1.00 -0.24 0.01 0.05 0.55 0.42 0.49 -- 0.14 0.75 -- 0.13PB 0.63 0.35 0.01 0.68 -0.01 0.05 -0.03 -0.02 -0.06 0.33 0.00 0.03 0.30 0.12 0.01 0.08 0.03 0.03 0.05 0.00 0.04 -0.05 0.02 -0.01 1.00 0.28 0.11 -0.15 -0.39 -0.14 -- -0.13 -0.22 -- 0.31S 0.35 0.06 -0.04 0.68 -0.04 -0.04 0.00 0.03 -0.08 0.00 0.12 -0.06 0.05 0.26 -0.05 0.04 0.06 -0.04 -0.02 -0.05 0.09 0.01 -0.02 -0.03 0.45 1.00 0.18 0.05 0.01 -0.03 -- 0.04 0.07 -- 0.01SB 0.30 0.11 -0.04 0.62 -0.01 -0.03 -0.01 0.06 -0.01 0.03 0.00 -0.03 -0.01 0.11 -0.07 0.12 0.03 -0.03 -0.05 -0.01 0.09 0.00 -0.02 -0.02 0.31 0.50 1.00 0.06 0.01 0.09 -- -0.05 0.10 -- 0.02SC -0.09 -0.01 0.68 -0.06 0.11 -0.14 0.46 0.21 0.02 0.07 0.77 0.49 0.21 0.66 0.52 0.00 0.09 -0.18 0.55 0.45 -0.05 0.26 0.37 0.10 -0.04 0.02 0.00 1.00 0.08 0.66 -- -0.28 0.87 -- 0.48SR -0.06 -0.06 -0.39 -0.10 -0.02 -0.13 -0.11 0.00 0.86 -0.01 -0.18 -0.17 -0.07 -0.38 -0.12 0.04 -0.19 -0.12 -0.16 0.07 -0.01 -0.27 0.03 0.34 -0.05 -0.08 -0.01 -0.15 1.00 0.04 -- 0.40 0.22 -- -0.33TI -0.07 -0.02 0.54 -0.08 0.19 -0.08 0.51 0.13 -0.06 0.03 0.64 0.32 0.16 0.45 0.33 -0.03 0.18 -0.11 0.40 0.23 -0.05 0.42 0.33 0.19 -0.04 0.00 0.01 0.63 -0.16 1.00 -- -0.20 0.69 -- 0.29TL -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --U -0.02 -0.02 -0.28 -0.02 -0.02 -0.07 -0.09 -0.05 0.44 -0.01 -0.19 -0.17 -0.06 -0.29 -0.11 0.00 -0.12 -0.06 -0.12 -0.07 0.01 -0.17 -0.06 0.33 -0.02 -0.04 -0.04 -0.18 0.53 -0.15 -- 1.00 -0.14 -- -0.32V -0.07 0.04 0.72 -0.06 0.11 -0.14 0.41 0.17 -0.01 0.15 0.81 0.43 0.30 0.70 0.56 0.02 0.08 -0.17 0.59 0.43 -0.06 0.33 0.39 0.17 0.00 0.01 -0.02 0.86 -0.14 0.75 -- -0.16 1.00 -- 0.37W -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --ZN 0.00 0.65 0.17 0.01 0.00 0.02 -0.02 -0.02 -0.07 0.98 0.11 0.06 0.88 0.15 0.09 -0.01 0.02 0.07 0.17 0.07 -0.01 -0.05 0.10 0.04 0.33 0.00 0.00 0.05 -0.06 0.02 -- -0.03 0.13 -- 1.00

Table Ⅱ－２－４　Result of principal factor analysis

STAT. Factor Load (analysis_log.sta)FACTORANALYSIS

Factor　　　Factor　　　Factor　　　Factor1 2 3 4

AU -0.044575 -0.525044 -0.267535 -0.187480AG 0.103167 -0.525622 0.047750 -0.201618AS -0.049336 -0.722442 -0.184563 0.164246B 0.170781 0.048043 0.186873 -0.209701BA -0.039951 -0.250912 0.571233 -0.098064BE 0.467034 0.002968 0.029829 -0.494155BI 0.255345 -0.043475 -0.212972 -0.618612CD 0.394263 -0.342496 0.094930 -0.022531CO 0.923743 0.054358 -0.095110 0.103450CR 0.591483 -0.161652 0.336658 -0.075409CU 0.802759 -0.190792 0.056104 0.020511GA 0.545123 0.124173 0.164499 0.246228HG 0.029282 -0.117452 -0.321921 -0.416105LA -0.227125 -0.242108 0.487014 -0.134870MN 0.684935 0.223354 -0.091646 0.173823MO -0.121535 -0.448761 -0.286948 0.143406NI 0.842229 -0.000976 -0.118366 0.014511PB -0.085052 -0.736655 0.333761 0.087255S 0.079445 -0.467762 -0.354021 0.388827SB 0.067967 -0.452544 -0.417529 -0.074347SC 0.909667 0.084525 -0.028660 0.007592V 0.903165 0.113433 -0.216886 0.045547ZN 0.573116 -0.313637 0.482386 0.086662説明済 5.864853 2.747569 1.814177 1.277476寄与率 0.254994 0.119460 0.078877 0.055542

Element

－131－

Chapter 3 Drilling Survey

3-1 Survey Method

1 Outline

The drilling survey has been performed in the three points shown in Figure

II-3-1 to make clear the geological structure, and state of mineralizaion and alteration

in the Aurora area.

MJZC-1 has been planed at Tlanilpa, where some mineral occurrences are

known, in the central north district for planed 350 meters deep. MJZC-2 has been

planned at the northwestern district, where some mineral occurrences exist but no

drilling has been done until now, for planned 250 meters deep. MJZC-3 has been

planned at the area to the south of the Aurora mineral occurrence in the central

district for planned 250 meters deep. These are all vertical holes.

A local contractor, Asesoria y Servicios de Perforacion, has conducted the

drilling.

The drilling cores have been inspected, and presented in drilling logs, 1/200 in

scale. In the same time, some color photos of the cores have been taken, and some

specimens for laboratory tests have been sampled. The all drilling-cores have been

kept in the CRM office in Teloloapan.

2 Drilling Method and Equipment

The drilling has been done using a Longyear 38 machine, and the wire line

method has been applied. Casing pipes have been inserted near the surface, if it was

necessary. Polymer or other chemicals have been used for preservation of boreholes in

response to the state of boreholes.

Table II-3-1 and II-3-2 show the principal machines and equipment for the

drilling.

3 Working Condition

Access road construction, arrangement removal were carried out one shift/day

and drilling work was in two shifts/day as a principal. Personnel for one drilling shift

－132－

consisted of one to two engineers and two to three workers. The base of survey was laid

in Tlanilpa and Otates. Daily necessities including food and fuels were provided by car

from Teloloapan.

4 Transportation of Equipment, Rig up and Tear Down

Tracks have been used for the move-in and transportation of the drilling

machine in the field through unpaved roads to the drilling site. The location of MJZC-1

is in a rugged terrain for transportation due to bad weather condition, accordingly the

transportation for several hundreds meters has to be relied on manpower. Preparation

of drilling site has been kept as much as small-scale considering environmental

preservation, and done by manpower. The drilling sites have been back to the original

state after moved out, and the drill hole have been covered by cement being recorded

the hole number and depth according to the CRM’s custom.

5 Drilling Water

In MJZC-1 and MJZC-3, enough volume of water could not obtained from the

nearby area, so that the necessary water had to be purchased from a pond for farming.

In MJZC-2, stream water has been pumped up, and reserved in the mud pit.

6 Progress of Drilling

Figure II-3-2 to Figure II-3-4 show the location of the drill holes, and Tables

II-3-3 and II-3-4 show the drilling result and process.

(1) MJZC-1

The drilling period is from October 3 to October 21. The wire line NQ drilling

method has been applied from the surface to the bottom of the hole. The drilling rate

has lowered, because troubles such as break of machine parts have happened, and

andesitic rocks having many cracks have been encountered below the depth of 270

meters.

－133－

(2) MJZC-2

The drilling period is from November 8 to November 15. The wire line NQ

drilling method has been applied from the surface to the bottom. The drilling has very

smoothly been done, because no trouble has happened, and all the rocks are stable.

(3) MJZC-3

The drilling period is from October 25 to November 6. The wire line NQ

drilling method has been applied. Troubles of the water pump have happened twice, so

that the drilling rate has lowered during the mid periods. However, the recovery rate

has not lowered, and the drilling has finished.

3-2 Survey Result

Figures II-3-5, II-3-6, and II-3-7 show the geological columner sections,

Figures II-3-8 shows the geological sections, and Tables II-3-5 and II-3-6 show the

assay result and laboratory test result.

1 MJZC-1

(1)Geology

・ 0－6.0 m: Cracked limestone and calcareous slate. Some weathered parts along

cracks.

・6.0－37.1m: Dacitic rock containing many plagioclase phenocrysts. The groundmass

is vitric, and shows dark gray due to argillization. Essential vitric fragments and rock

fragments of underlying porphyritic andesite and fine-grain rocks are contained. Below

24.5 meters, pyroxene andesite cobles and boulders are contained. Under the

microscopic observation of the rock specimen at 32 meters, altered plagioclase

phenocrysts, chlorite, calcite, and iron minerals are seen.

・37.1－53.2 m: Green andesitic tuff to lapilli tuff. The matrix is mainly vitric.

Accessory porphyritic andesite, accidental silicified micro-grained pyrite are contained.

Around 40 to 41 meters depth, rocks change to sandy tuff, and grading structure is

seen. Beds incline 20 degrees. In the X-ray diffraction analysis, large amounts of

－134－

chlorite and small amounts of sericite, calcite, and dolomite are detected in the rock

specimen at 45.5 meters.

・53.2－67.3 m: Reddish to yellowish-greenish gray andesite lava partly showing

opaque autobrecciated structure. Hematite contains in reddish parts and chlorite in

yellowish green parts. Below 61 meters, silicification makes leaching. In the X-ray

diffraction analysis, small amounts of chlorite, sericite, and calcite are detected.

・67.3－121.5 m: Andesitic lapilli tuff to hyaloclastite. Much chloritized accessory

andesite fragments are contained, being accompanied by small amounts of silicified

rocks and green andesite fragments. The groundmass is fine-grained green glass, being

accompanied by chip-like essential glass fragments with plagioclase phenocrysts. At

104.2 meters and 109.8 meters, rocks change to course-grained tuff. The bedding

inclines about 30 degrees. At 92.7 meters, a 10 cm width small fault inclining 50

degrees containing solid cemented clay is seen.

・121.5－145.0 m: Greenish to yellowish-greenish-gray massive, compact andesite lava.

Small amounts of coarse-grained plagioclase and pyroxene phenocrysts, smaller than 3

millimeters in diameter, are contained. No breccia structure is seen. This part is

gradually changed to the underlying layer. Under the microscopic observation of the

sample at 132.5 meters, altered plagioclase set in intersertal groundmass

accompanying chlorite and calcite are seen.

・145.0－150.2 m: Andesitic lapilli tuff to hyaloclastite containing altered accessory

andesite and essential glass fragments. The fragments are 1 to 5 cm in size. The rocks

contact with lower andesite by fracture zone.

・150.2－221.7 m: Andesite lava. About 10 meters thick upper zone shows bluish green

and fine-grained parts, being possible sheared zone. Most parts are of chloritized

massive porphyritic rocks. The lower boundary zone is fine-grained and vitric. Sheared

zones exist at 166.4m and in 198.7 to 199.0 meters.

・221.7－269.5 m: Andesitic lapilli tuff to hyaloclastite, having same facies as of the

upper layer. They show same facies as that of the upper layer. These rocks contain

yellowish green andesitic accessory fragments, and fine-grained andesite and silicified

rock fragments. Under the microscope, plagioclase fragments, chlorite, calcite are

－135－

observed in chlorite altered groundmass.

・269.5－321.8 m: Andesitic tuff and lapilli tuff. Tuff mainly consists of green glass,

being accompanied by green andesite and silicified rock fragments, but volume of

fragments is smaller than that of the upper layer. In 286.2 meters to 300 meters and

303.5 meters to 307 meters, chloritized sheared zones exist.

・321.8－326.5 m: Massive, compact, fine-grained andesite lava. Strong hematite,

chlorite alteration are seen. The lower boundary is of high angle, sheared zone.

・326.5－350.1 m: Yellowish-grayish-green brecciated lava or lapilli tuff with strong

chloritization. Green glass fragments are seen in fine-grained groundmass. Sheared

zone is accompanied by clay in 340.5 to 344.3 meters.

(2) Mineralization and Alteration

A significant mineralized part is seen in the upper part of dacite. It is of the

fine-grained pyrite dissemination and network. Some specimens taken at the depths of

11.8 meters and 28.4 meters have been examined by observation of polished section,

X-ray diffraction, and chemical assay. The assay result is as follows.

0.03 ppm Au, 0.75 to 5.50 ppm Ag, 25 to 32 ppm Cu, 9 to 32 ppm Pb,

36 to 93 ppm Zn, 103 to 201 ppm Ba, 5.17 to 7.17 % Fe, 4.07 to 7.07 % S

In the X-ray diffraction analysis, sericite, chlorite, calcite, and pyrite are

detected. In the polished section, fine-grained pyrites occurred in spaces between

fragments, and colloform structure is partly seen. Fine pyrite grains also exist in the

fragments. No other ore minerals are seen.

At 183.5 meters, 192.6 to 193.3 meters, and 194.7 to 195.4 meters,

calcite-quartz-pyrite veins exist. The assay result of the sample at 192.8 meters is as

follows.

0.03 ppm Au, 0.35 ppm Ag, 22 ppm Cu, 17 ppm Pb, 34 ppm Zn,

172 ppm Ba, 4.53 % Fe, 3.06 % S

Sericite, chlorite, calcite, pyrite, and quartz are detected as alteration

minerals. In the polished section, irregular to idiomorphic pyrites are observed in

quartz veins, and small amounts of fine-grained pyrite are disseminated there.

－136－

2 MJZC-2

(1) Geology

・0.8－8.1 m: Mainly brownish gray weathered schistose rocks.

・8.1－37.0 m: Dark green to grayish green andesitic tuff to lapilli tuff. Foliation planes

are well developed, and banded structure is partly seen. Essential gravels are

confirmed up to the depth of 17 meters, but tend to be flattened. Hematite increases to

the lower part, rock color turns to reddish. This layer gradually changes to the lower

layer. In the X-ray diffraction analysis, of the rock at 17.5 meters, mainly sericite and

calcite, chlorite, and pyrite are detected.

・37.0－55.8 m: Schistose rock with banded structure due to chlorite rich layers and

sericite rich layers with well developed foliation and cleavage. It is possibly that the

source rock is andesitic tuff. Green flattened glass chips are seen. Under the

microscope, the sample at 46.3 meters shows lepidoblastic texture, and quartz, calcite,

chlorite, and sericite align along schistosity. Inclination of foliation plane is 10 degrees.

The contact plane between upper and lower layers is 40 degrees.

・55.8－82.0 m: Altered fine-grained to aphanitic andesite intrusive rock. The rock

shows generally greenish gray, but partly gray networks are seen. It is thought that

fine-grained green spots are of chloritized mafic mineral phenocrysts or glass. In 75 to

78 meters, brecciate to shearing structure is seen. In 79.5 to 82 meters, rock is mixed

with the lower schistose rock.

・82.0－187.0 m: Banded schistose rock of chlorite rich layers and sericite rich layers.

Partly plagioclase phenocrysts, flattened green glass and pumice are contained. Rarely

altered fragments are seen. Foliation plane and cleavage inclines 20 to 50 degrees.

Rocks in 105.5 to 109.5 meters are possibly acidic rocks origin due to dominant quartz

and sericite. Rocks in 184 to 184.9 are of green basic schistose rock.

・187.0－250.0 m: Dark green basic volcanic rock, originally schistose rocks. Plagioclase

relicts are confirmed in many places. In 209.6 to 228 meters, opaque, deformed,

autobrecciated structure is seen. Inclination of schistosity is 10 to 45 degrees. In the

X-ray diffraction analysis of the rock at 218.7 meters, large amounts of chlorite and

calcite, medium amounts of sericite and dolomite, and small amounts of pyrite are

－137－

seen.

(2) Mineralization and Alteration

Networks and silicified zones formed by quartz, calcite, and pyrite are seen in

the andesite. Its hanging and footwall schistose rocks have been disseminated by

pyrite, maximum 5 %, and some film-like mineralized parts are seen. In the assay

result of the rock at 80.6 meters is as follows.

<0.01 ppm Au, <0.01 ppm Ag, 33 ppm Cu, 7 ppm Pb, 48 ppm Zn,

327 ppm Ba, 4.75 % Fe, 2.09 % S

In the polished section of the same specimen, some fine-grained pyrite

network and minor amounts of limonite altered from magnetite are seen. In the X-ray

diffraction analysis, chlorite, calcite, and pyrite are detected

The maximum values of the assay result of the specimens from 45.5, 115.8,

and 128.0 meters are as follows

0.12 ppm Au, 0.45 ppm Ag, 23 ppm Cu, 26 ppm Pb, 198 ppm Zn,

336 ppm Ba, 6.58 % Fe, 6.19 % S

In the polished section, slightly coarse-grained irregular and idiomorphic

pyrite are only seen. In the X-ray diffraction analysis of the specimen at 45.5 meters,

chlorite, sericite, pyrite, and dolomite are detected.

3 MJZC-3

(1) Geology

・0－7.5 m: Talus deposits consisting of weathered yellowish tuff, sandstone, and soil.

・7.5－11.0 m: Weathered yellowish tuffaceous sandstone.

・11.0－34.1 m: Mainly black slate, being accompanied by fine-grained tuffaceous

fragment and mineralized breccia. Alternation of thin layers of those is seen. In 18.6 to

22.45, the rock is calcareous. Inclination of beds is about 45 degrees. Weak

dissemination and films of pyrite, and calcite veinlets are seen.

・34.1－39.5 m: Pale yellowish gray vitric fine-grained tuff. Slump-like structure is seen,

and mud ball-like slate is included inside. Under the microscopic observation,

－138－

specimen at 34.6 meters plagioclase fragment is seen in the vitric groundmass. In the

X-ray diffraction analysis, chlorite, calcite, sericite, and pyrite are detected.

・39.5－53.1 m: Irregular alternation of black slate and tuff. Slate is dominant in the

upper part being accompanied with lenticular tuff, and tuff is dominant in the lower

part. Sandy limestone beds are intercalated in 45.8 to 46.8 meters. Small amounts of

pyrite films and mineralized fragments are in the whole section. Inclination of beds is

about 20 degrees.

・53.1 - 78.5 m: Massive coarse-grained dacite to salic andesite intrusive rock. The

upper boundary inclines 20 degrees, and lower boundary gradually changes to

fine-grained rock. The rock is greenish gray and contains relatively large amounts of

plagioclase phenocryst, 1 to 2 millimeters in size, and colored minerals. Steep angle

calcite veins are distributed in the rock. Little pyrite dissemination nor foliation planes

exist. Under the microscope, the rock at 65.6 meters is judged pyroxene andesite

containing amphibole. In the X-ray analysis, chlorite and calcite are detected.

・78.5－126.8 m: Mainly black slate being accompanied by thin layer and fragmental

vitric tuff. Vitric tuff in 85.1 to 87.7 meters, and calcareous slate in 119.8 to 122.3

meters are dominant. Under the microscope, rocks at 121.8 meters show aligned large

amounts of calcite and small amounts of quartz grains along schistosity. Small

amounts of lenses and films of pyrite and mineralized fragments are seen along

bedding planes. Bedding inclines 20 to 40 degrees. Small-scale overturned folding

structure is seen at 87.4 meters.

・126.8－131.2 m: Tuffaceous breccia. Lithic lapilli stone like part and muddy

fragments are contained.

・131.2－132.5 m: Alternation of well stratified tuff and slate. The rock gradually

changes to lower calcareous slate.

・132.5－136.2 m: Calcareous slate and limestone showing cleavage and bedding planes.

Thin layers of fine-grained pyrite are intercalated. Cleavage and bedding planes

incline 50 degrees.

・136.2－137.6 m: Yellowish gray vitric tuff containing plagioclase phenocrysts.

・137.6－139.7 m: Calcareous limestone with foliation and bedding planes. The rock

－139－

gradually changes to lower breccia.

・139.7－144.8 m: Breccia containing silicified andesite fragments and mineralized rock

fragments ( micro-grained pyrite dissemination).

・144.8－170.0 m: Grayish blue to bluish green autobrecciated andesite lava. Small

amounts of plagioclase and pyroxene phenocrysts exist. Calcite veins are distributed in

the whole section. Gray quartz fills openings of breccia. The contact plane with the

lower layer declines 70 degrees with sheared zone. Under the microscope, the specimen

at 166.0 meters is altered andesite showing intersertal texture. In the X-ray diffraction

analysis of the same specimen, chlorite, and small amounts of sericite, quartz, and

calcite are detected.

・170.0－173.9 m: Dacitic breccia. The upper part is of lapilli tuff containing accidental

silicified fragments. Main component is brecciated vitric lava containing plagioclase

phenocrysts. At the unit boundary at 173.9 meters, phenocryst increases.

・173.9－187.9 m: Grayish green dacitic and andesitic tuff to breccia. Fine-grained

plagioclase is spotted, but mostly green vitric groundmass. The boundary with the

lower unit turned to dark gray vitric groundmass. In the X-ray diffraction analysis of

the specimen at 186.5 meters, some chlorite, and small amounts of calcite and sericite

are detected.

・187.9－199.7 m: Andesitic lapilli tuff and hyaloclastite. The groundmass is mostly

vitric, and contains some fragments of accessory fine-grained porphyritic andesite and

coarse-grained chloritized andesite. The rock gradually changes to autobrecciated lava

of lower layer.

・199.7－250.0 meters: Dark green to grayish green autobrecciated lava. The rock is

generally vitric, but being accompanied by small amounts of plagioclase phenocrysts.

Hyaloclastite principally consisting of green glass balls in 220.0 to 222.5 meters is the

boundary of the unit. Under the microscope, the specimen at 204.5 meters is of

brecciated rock consisting of plagioclase phenocrysts and groundmass showing

intersertal texture. In the X-ray diffraction analysis of the specimen at 186.5 meters,

some chlorite, and small amount of calcite and sericite are detected.

－140－

(2) Mineralization and Alteration

The sedimentary rocks and dacitic breccia above the andesite contain small

amounts of fine-grained pyrite dissemination, films and thin layers, and mineralized

fragments. The maximum values for each element in the chemical assay, for eight

samples, are as follows.

0.18 ppm Au, 1.05 ppm Ag, 46 ppm Cu, 24 ppm Pb, 253 ppm Zn,

771 ppm Ba, 5.55 % Fe, 4.35 % S

In the polished section of eight specimens, most of the mineralized parts are of

pyrite dissemination and fragments of fine-grained pyrite dissemination. In the

specimen taken at the depth of 91.2 meters, pyrite is accompanied with minor amounts

of chalcopyrite. In the specimens take at the depth of 107.8 meters and 114.8 meters, a

little colloform texture and framboidal texture have been observed.

4 Laboratory test (fluid inclusion test and isotopic analysis)

(1) Fluid Inclusion Test

The test has been conducted for three specimens as shown in Tale II-3-5(4).

The test could not be achieve for the two specimens of MJZC-1, because the size of their

inclusions are too small (smaller than 1μm), and they contain too much gas inclusion.

The specimen taken at the depth of 131.5 meters (MJZC-3) is of quartz from a

layered white mineral vein in the stratified tuff. The homogenized temperature of the

inclusion ranges between 220゜and 270゜C, forming a single population. The salinity

ranges between 3 and 4 percent. It is possible that the homogenization temperature

reflects the hydrothermal activity of film-like pyrite in surroundings.

(2) Isotopic Analysis

The oxygen isotope (δ18O) of silicates and the carbon (δ13C) and oxygen

isotopes of carbonates for analysis are shown in Table II-3-5(5).

The dacite taken at the depth of 32 meters in MJZC-1 has been measured for

the oxygen isotope on silicates. δ18O is 15.1 per mil, which is approximately same

value as that of the dacite on the surface to the south of the drill hole (14.5 and 15.8 per

－141－

mil). δ13C andδ18O of the limestone taken at the depth of five meters are -0.6 per mil

and -14.5 per mil respectively, lower than those of the limestone on the surface (δ13C;

1 per mil, δ18O; 9.5 per mil).

Two specimens taken at the depth of 34.6 meters (dacite tuff) and 186.5

meters (andesite) in MJZC-3 have been measured for oxygen isotope on silicates. δ18O

of dacite tuff and andesite are 15.5 per mil and 15.1 per mil respectively. These values

indicate no significant alteration but are equivalent to the background of surface

samples.

Two specimens taken at the depth of 45.5 meters (calcareous slate) and 138.2

meters (limestone) in MJZC-3 have been measured for oxygen isotope and carbon

isotope on carbonates. δ13C values on carbonates of these core samples show -5.6 per

mil (45.5m) and -2.4 per mil (138.2m), and alsoδ18O values are -14.2 per mil (45.5m),

-14.5 per mil (138.2m). It is considered that these indicate hydrothermal calcite origin.

Teloloapan

Taxco

Geo

logi

cal S

ecti

on L

ine

MJZC-1(350m)

Geological Section Line

WSW

ENE

MJZC-2(250m)

Geological Section LineW EMJZC-3(250m)

Name Type Specification No.

Engine type "DETROIT"

50H.P、1500RPM

Volume：20GPM

Max Pressure：400psi

Motor：17.5H.P　1800RPM

Outer tube(NQ) 3.05m 2pc

Inner tube(NQ) 3.05m 3pc

Casing pipe NW　3.05m 20pc

Rod(NQ-WL) NQ　3.05m 125pc

Truck 1t 1pc

Truck 3.5t 1pcTransport

Rod,Outer tube,

etc

Table Ⅱ－３－１ List of drilling equipment

L-38（LONG　YEAR)

420RT（BEAN　ROYAL)

1pc

2pc

Drilling Machine

Drilling Pump

MJZC-1 MJZC-2 MJZC-3

Drilling rod NQ CN×3.05m pc 114 81 81 276

Casing pipe(NW) 76.2mm×3.05m pc 2 3 3 8

Outer tube(NQ) 12-400-05 pc 1 0 0 1

Inner tube(NQ) 12-400-03 pc 2 0 0 2

Inner tube head(NQ) 12-400-00 pc 1 0 0 1

Overshot 13-400-00 pc 1 0 0 1

Wireline rope 5mm×450m ｍ 350 0 0 350

Casing shoe bit 76.1mm×91.8mm pc 1 0 0 1

Diamond bit NQ pc 2 2 2 6

Diamond reamer NQ pc 1 0 0 1

Stabilizer NQ pc 1 1 1 3

Core lifter NQ pc 3 1 2 6

Core lifter case NQ pc 0 1 1 2

Pipe for water 　 ｍ 550 350 600 1,500

Cement kg 350 200 350 900

Polymer kg 15 10 8 33

Diesel l 2,400 1,600 1,600 5,600

Gear oil l 19 0 19 38

Hydraulic oil l 20 19 0 39

Engine oil l 150 0 19 169

Glees kg 19 19 19 57

Total

Table Ⅱ－３－２ List of used diamond bits and consumption goods

QuantityDescription Specification Unit

CLASS TOTAL DAYSACTUALWORKING

DAY OFF WORKERS

RIG UP ～ 2002.10. 2 6 6 0 46

DRILLING ～ 2002.10.21 19 19 0 188

TEAR DOWN ～ 1 1 0 7

TOTAL ～ 2002.10.22 26 26 0 241

350.00 OVERBURDEN(m) - DEPTH(m)CORE

LENGTH(m)CORE

RECOVERY(%)CUMULATIVE(%

)

- CORE LENGTH(m) 342.70 0.00～115.10 109.40 95.05 95.05

350.10 RECOVERY(%) 97.89 115.10～204.20 89.05 99.94 97.18

204.20～310.00 105.80 100.00 98.15

(h) (%) (%) 310.00～350.10 38.45 95.89 97.89

247 61.21 50.67

108 26.77 22.15 TOTAL DEPTH(m)/TOTAL

WORKING DAYS13.47 /DAY

48.5 12.02 9.95 TOTAL DEPTH(m)/ACTUAL

WORKING DAYS13.47 /DAY

TOTAL DEPTH(m)/TOTALDRILLING DAYS

18.43 /DAY

403.5 100.00 82.77 TOTAL DEPTH(m)/ACTULDRILLING DAYS

18.43 /DAY

72 14.77 TOTAL DEPTH(m)/TOTALWORKERS

1.45 /WORKERS

12 2.46ACTUAL DRILLINGWORKERS

/TOTALDEPTH(m)

0.54 /ｍ

487.5 100.00

B/A×100(%)

RECOVERY

（％）

SIZE SET DEPTH

NW (76.2) 8.00 2.29 100.00

TRIP,CORERECOVER,CASING,etc

REPAIR,FISHING

DRILLING DEPTH etc.

PROPOSED DEPTH

ADDITIONAL DEPTH

　A　：　TOTAL　DEPTH　B　：　SET　DEPTH

TOTAL

SIZE（mm)

WORKING PERIOD

TIME ANALYSYS

2002. 9.27

2002.10. 3

2002.10.22

2002. 9.27

OTHER

TableⅡ-3-3 Drilling　Summary（MJZC-1)

PENETRATION RATE

CORE RECOVERY PER EACH 100m

REMARKS

（SUB-TOTAL）

INSPECTED DEPTH

RIG UP

TEAR DOWN

COTEGORY

DRILLING

CLASS TOTAL DAYSACTUALWORKING

DAY OFF WORKERS

RIG UP ～ 2002.10.24 2 2 0 14

DRILLING ～ 2002.11. 6 12.5 12.5 0 87.5

TEAR DOWN ～ 0.5 0.5 0 3.5

TOTAL ～ 2002.11. 6 15 15 0 105

250.00 OVERBURDEN(m) 7.20 DEPTH(m)CORE

LENGTH(m)CORE

RECOVERY(%)CUMULATIVE(%

)

- CORE LENGTH(m) 244.55 0.00～98.55 93.10 94.47 94.47

250.00 RECOVERY(%) 97.82 98.55～196.70 98.15 100.00 97.23

196.70～250.00 53.30 100.00 97.82

(h) (%) (%)

196 64.90 57.99

43 14.24 12.72 TOTAL DEPTH(m)/TOTAL

WORKING DAYS16.67 /DAY

63 20.86 18.64 TOTAL DEPTH(m)/ACTUAL

WORKING DAYS16.67 /DAY

TOTAL DEPTH(m)/TOTALDRILLING DAYS

20.00 /DAY

302 100.00 89.35 TOTAL DEPTH(m)/ACTULDRILLING DAYS

20.00 /DAY

24 7.10 TOTAL DEPTH(m)/TOTALWORKERS

2.38 /WORKERS

12 3.55ACTUAL DRILLINGWORKERS

/TOTALDEPTH(m)

0.35 /ｍ

338 100.00

B/A×100(%)

RECOVERY

（％）

SIZE SET DEPTH

NW (76.2) 7.70 3.08 100.00

TableⅡ-3-3 Drilling　Summary（MJZC-2)

PENETRATION RATE

CORE RECOVERY PER EACH 100m

REMARKS

（SUB-TOTAL）

RIG UP

TEAR DOWN

COTEGORY

DRILLING

TRIP,CORERECOVER,CASING,etc

　A　：　TOTAL　DEPTH　B　：　SET　DEPTH

TOTAL

SIZE（mm)

WORKING PERIOD

TIME ANALYSYS

2002.10.23

2002.10.25

2002.11. 6

2002.10.23

OTHER

REPAIR,FISHING

DRILLING DEPTH etc.

PROPOSED DEPTH

ADDITIONAL DEPTH

INSPECTED DEPTH

CLASS TOTAL DAYSACTUALWORKING

DAY OFF WORKERS

RIG UP ～ 1 1 0 7

DRILLING ～ 2002.11.15 8 8 0 56

TEAR DOWN ～ 1 1 0 7

TOTAL ～ 2002.11.16 10 10 0 70

250.00 OVERBURDEN(m) 8.10 DEPTH(m)CORE

LENGTH(m)CORE

RECOVERY(%)CUMULATIVE(%

)

- CORE LENGTH(m) 244.25 0.00～118.60 112.60 94.94 94.94

250.25 RECOVERY(%) 97.60 118.60～195.95 77.35 100.00 96.94

195.95～250.25 54.30 100.00 97.60

(h) (%) (%)

128 74.42 65.98

28 16.28 14.43 TOTAL DEPTH(m)/TOTAL

WORKING DAYS25.03 /DAY

16 9.30 8.25 TOTAL DEPTH(m)/ACTUAL

WORKING DAYS25.03 /DAY

TOTAL DEPTH(m)/TOTALDRILLING DAYS

31.28 /DAY

172 100.00 88.66 TOTAL DEPTH(m)/ACTULDRILLING DAYS

31.28 /DAY

10 5.15 TOTAL DEPTH(m)/TOTALWORKERS

3.58 /WORKERS

12 6.19ACTUAL DRILLINGWORKERS

/TOTALDEPTH(m)

0.22 /ｍ

194 100.00

B/A×100(%)

RECOVERY

（％）

SIZE SET DEPTH

NW (76.2) 3.15 1.26 100.00

TRIP,CORERECOVER,CASING,etc

REPAIR,FISHING

DRILLING DEPTH etc.

PROPOSED DEPTH

ADDITIONAL DEPTH

　A　：　TOTAL　DEPTH　B　：　SET　DEPTH

TOTAL

SIZE（mm)

WORKING PERIOD

TIME ANALYSYS

2002.11. 7

2002.11. 8

2002.11.16

2002.11. 7

OTHER

TableⅡ-3-3 Drilling　Summary（MJZC-3)

PENETRATION RATE

CORE RECOVERY PER EACH 100m

REMARKS

（SUB-TOTAL）

INSPECTED DEPTH

RIG UP

TEAR DOWN

COTEGORY

DRILLING

Hole Name Item September

Transportation 27 2

MJZC-1 Drilling 3 　21

Tear down 22

Rig up 7

MJZC-2 Drilling 8 15

Tear down 16

Rig up 23 24

MJZC-1 Drilling 25 6

Tear down 6

Table Ⅱ－３－４ Drilling schedule

October Novmber

Note

(others)

1 MJZC-1(32m) altered andesite ・ △ ・ ・ ○ ・ △ △ intersertal texture

2 MJZC-1(45.5m) altered brecciated andesite ・ △ ・ ○ △ △ △ brecciated with intersertal texture

3 MJZC-1(132.5m) altered andesite ・ △ ・ ・ ○ ・ △ △ intersertal texture

4 MJZC-1(263.2m) altered andesite (tuff) △ △ ・ △ ・ △ ・

5 MJZC-2(46.3m) calcarious quartz sericite sch○ ○ ○ ・ ○ △ lepidoblastic texture

6 MJZC-2(64m) altered andesite ・ △ ・ ・ ○ ・ △ △ intersertal texture

7 MJZC-2(165.5m) calcarious quartz sericite sch○ △ ○ ・ ○ △ lepidoblastic texture

8 MJZC-2(190.5m) calcarious quartz sericite sch○ △ ○ ・ ○ △ lepidoblastic texture

9 MJZC-3(34.6m) altered andesite (tuff) △ △ ・ △ ・ △ ・

10 MJZC-3(65m) pyroxene andesite △ △ ・ △ ・ △ ・ △ ・ intersertal texture

11 MJZC-3(121.8m) calcarious quartz schist ○ ・ △ ・ ◎ lepidoblastic texture

12 MJZC-3(124.1m) brecciated tuff ・ ○ ・ ・ ・ △ △ cataclastic? with lepidoblastic texture

13 MJZC-3(166m) altered andesite ・ △ ・ ○ ・ △ △ intersertal texture

14 MJZC-3(186.5m) altered andesite ・ △ ・ ○ ・ △ △ intersertal texture

15 MJZC-3(204.5m) altered brecciated andesite ・ △ ・ ○ ・ △ △ brecciated with intersertal texture

Legend; ◎,abundant; ○, common; △, minor; ・rare

qz:quartz, pl:plagioclase, K-f:K feldspar, am:amphibole, opx:ortho pyroxene, cpx:clino pyroxene, ol:olivine

se: sericite, chl:chlorite, ca:carbonate mineral (mainly calcite), opa:opague minerals

Table Ⅱ－3－5(1) Result of laboratory test(Thin section for core sample)

Sample No. Rock Name

Minerals

No.qz pl K-f amopxcpxol opasechlepi ca

Note

py As Mc sph gn cp Th Bo ilm Ba Cv Rt (others)

1 MJZC-1 ８．１ｍ ◎

2 MJZC-1 ２８．４ｍ Pyrite Network ◎ Colloform

3 MJZC-1 １９２．８ｍ Q-Cal-Py vein ○

4 MJZC-2 ４３ｍ Pyrite lens, diss ◎

5 MJZC-2 ８０．５ｍ Pyrite Network △

6 MJZC-2 １１５．８ｍ Pyriet dissemination, frag △

7 MJZC-3 ４２．０ｍ Pyriet dissemination, frag ◎

8 MJZC-3 ９２．１ｍ Pyrite lens, diss ◎ ・

9 MJZC-3 １０６．６ｍ Pyrite dissemination band △ ・

10 MJZC-3 １０７．８ｍ Pyrite film, dissemination △ Colloform、framboidal

11 MJZC-3 １１４．８ｍ Pyrite film, dissemination △ ・

12 MJZC-3 １３１．５ｍ Pyrite film, dissemination ○

13 MJZC-3 １３４．８ｍ Pyrite film, dissemination ○ Framboidal

14 MJZC-3 １４１．３ｍ Brecciated △

15 MJZC-3 １７１．５ｍ Brecciated △ ・

Legend; ◎,abundant; ○, common; △, minor; ・rare

Py:pyrite, As:arsenopyrite, Mc: marcasite, Sph:sphalerite, Gn:galena, Cp:chalcopyrite, Th:tetrahedorite,

Bo:bornite Po:pyrrhotite, Cv:covelline, Ba:barite, Rt:rutile

Ore minerals

Table Ⅱ－3－5(2) Result of laboratory test(Polished section for core sample)

No. Sample No Location Sample Type

Sulphide network

Qz Ab Kf Sm Ha K Ch S S3 Pg Gp Ba Ja Ca Do Py Gn Sph Px Hb Ep

1 11.8m Dacite △ △ △ △ ○ ・ △ ・ pyrite dissemination

2 28.4m Dacite △ ○ ・ △ ・ ・ △ ・

3 45.5m Andesite △ ・ ○ ・ ・ △

4 54.5m Andesite ○ ◎ ・ ・ ・ ・

5 192.8m Andesite ○ ○ ・ ○ ○ △ pyrite vein

6 17.5m Foliated tuff △ △ ・ △ ◎ ・

7 45.5m Foliated tuff ○ △ ・ ◎ ・ △ pyrite dissemination

8 80.6m Andesite ○ △ ○ △ ◎ ・

9 218.7m Andesite ○ ・ ○ △ ◎ △ ・

10 34.6m Tuff △ ○ △ ・ ○ ・

11 65.6m Andesite ○ ○ △ △ △

12 124.1m Slate>tuff ○ △ ○ ・ △ ・

13 166.0m Andesite ○ △ △ ・ ・ ・

14 186.5m Andesite ・ ○ ○ ・ △

Legend; ◎,abundant; ○, common; △, minor; ・rare

Qz:quartz, Ab:albite, Kf:K feldspar, Sm:smectite, Ha:halloysite, K: kaolinite, Ch:chlorite, S;sericite,S3;sericite(3T), Pg:palagonite, Gp:gypsum,

Ba:barite, Ja:jarosite, Ca:calcite, Do: dolomite, Py:pyrite, Gn:galena, Sph:sphalerite, Px:pyroxene, Hb:horblende, Ep:epidote

Detected Minerals

Table Ⅱ－3－5(3) Result of laboratory test(X-ray diffraction for core sample)

No. Sample No, Rock name, type

MJＺＣ-2MJＺＣ-2

RemarksSilica M Feldspar M Clay Minerals Sulphate M Other Minerals

MJＺＣ-1

MJZC-3MJZC-3

MJＺＣ-2MJZC-3MJZC-3MJZC-3

MJＺＣ-1MJＺＣ-1

MJＺＣ-1MJＺＣ-2

MJＺＣ-1

Temperature（℃）No. range average S.D.1 MJZC-3 131.5m Quartz 20 223～277 245.9 14.1 Size＝5.0～17.5μm2 MJZC-1 28.4m Quartz － － － － 1μgass inclusion3 MJZC-1 192.8m Calcite － － － － 1μgass inclusion

Frozn temp（℃） salinity(wt%)Min. Max. Ave. Min. Max. Ave.

1 MJZC-3 131.5m Quartz 10 -2.5 -1.6 -1.98 2.90 4.18 3.352 MJZC-1 28.4m Quartz － － － － － － － No data3 MJZC-1 192.8m Calcite － － － － － － － No data

ＭＪZC-3 131.5m

Mineral Quartz

Number 20

Max. 277 ℃

Min. 223 ℃

Average 249.5 ℃

S.D. 14.1

Temperature

Table Ⅱ－3－5(4) Result of laboratory test(fluid inclusion test,temperature)

Table Ⅱ－3－5(4) Result of laboratory test(fluid inclusion test,salinity)

Form

Frequency

remarksNo. Sample name mineral Number

Sample name mineralinclusion no.

0

1

2

3

4

5

6

7

8

9

200 210 220 230 240 250 260 270 280 290 300

Table Ⅱ－3－5（5） Result of laboratory tests （Isotope, for core samples）

Oxygen isotope

Sample Rock Name treated for carbonate Yield δ18O(SMOW)

MJZC-1, 32.0m dacite treated 20% HCl 14.0 15.1

MJZC-3, 34.6m dc tuff treated 20% HCl 14.4 15.5

MJZC-3, 186.5m Alt Ad treated 20% HCl 15.1 15.1

Oxygen isotope and carbon isotope on carbonates

Sample Rock Name δ13C δ18O

MJZC-1 5.0M CALC SLATE/ls -0.6 -14.5

MJZC-3 45.5M CALC SLATE -5.6 -14.2

MJZC-3 138.2M CALC SLATE/ls -2.4 -14.5

－173－

Part Ⅲ Conclusions and Recommendation

Chapter 1Conclusion

Following surveys are carried out in second year: The geological and

geochemical survey in the Aurora area and the Rancho Viejo area, the detail geological

survey in the Santiago Salinas area and three drilling survey in the Aurora area.

The geology of the Aurora area is composed of the Villa Ayala Formation, the

Pachivia Formation and intrusive rocks.

The Villa Ayala Formation is composed of schistose volcanic rocks (Lsh),

schistose sedimentary rocks (Lss), andesites (Va1～Va6, Vam), dacite (DCw, DCe, DCn,

DCc, Vad) and sedimentary rocks (Us, Ust, Ms).

The Pachivia Formation consists of the layers (CFm) that are mainly

composed of slate and volcanic rocks (CFv).

The geological structure is complicatedly controlled by the folding and fault

structures whose axis is NNE to NNW with the gently inclined cleavage. As a whole,

andesite Va-1 is located in the central part and sedimentary rocks surround it, the

outsides of the sedimentary rocks andesites Va-2～Va-5 are distributed. Dacite rock

bodies are distributed in the south west and south east of the area and schistose

volcanic rocks and sedimentary rocks occupy in the corner of the northwestern part of

the area. The Pachivia Formation is distributed in a belt with the direction of north to

the south in the eastern part of the area. The Formation dips westward in appearance,

but the horizon is judged to be overturned by the fossil age and the folding pattern.

There are massive sulfide type ore deposit and metalliferous vein type ore

deposit as the mineralization of the Aurora area. Within the above massive sulfide ore

deposit, the Capire, the Aurora and the Manto Rico ore deposit occur within the

sedimentary rocks of the upper part of the Villa Ayala Formation. On the other hand,

the Guadalupe and the Cruz Blanca deposit occur within the uppermost part of the

Pachivia Formation. These ore deposits are relatively rich in Pb, Zn, Ag and Ba. As a

result of this year’s survey, the Santiago Salinas district and the La Campana district

were found as the place of ore showing. The detail geological survey was carried out in

the Santiago Salinas district and confirmed the horizon of occurrence of massive

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sulfide ore deposit.

Based on the geochemical survey, the zone that shows more than +1σ of

average alteration index of each rock facies is considered to reflect the halo of the

alteration related to the massive sulfide alteration. It became obvious that there are

high possibility of that Ag, As, Zn, Pb, Cd and Ba as the trace elements to the

indication elements for metalliferous vein type and Au, Ag, As and S as the indication

elements for massive sulfide type ore deposit are effective. Besides the above, principal

component analysis can extract the anomaly related to the mineralization in the La

Campana, the south of Velixtla, the Santiago Salinas and around the Capire to the

Aurora deposits.

The horizon of massive sulfide ore deposit was observed in the shallow part of

the drilling hole MJZC-1. Sulfide network was also observed within the footwall dacite.

This horizon continues to the place of mineralization indicate of Tlanilpa and the

drilling hole TN-14 that was already drilled. Drilling hole MJZC-2 intersected volcanic

rocks that develop schistosity. Though the volcanic rocks show strong pyrite

dissemination, the horizon of these volcanic rocks were judged to be lower than the

horizon of massive sulfide ore deposit. Drilling hole MJZC-3 intersected the

sedimentary rock that is the same as the host rocks of the Capire and the Aurora

deposit were observed in the depth of 149.5 meters. The weak pyrite dissemination and

mineralized rock fragments were sampled in the same depth. Under the sedimentary

rock, andesite lava of the Villa Ayala Formation that corresponds to andsite Va-4 of the

surface was observed.

The geology of the Rancho Viejo area is composed of the Villa Ayala Formation,

the Pachivia Formation.

The Villa Ayala Formation is composed of basalt to andesitic rocks (Va) and

dacite (Vd). The quantity of the dacite is less than that in the Aurora area.

The Pachivia Formation is composed of basalt to andesitic tuff (CFv),

limestone (CFL), slate (CFs), and alternation of tuff and slate (CFt).

As the geological structure, cleavage with the direction of NNE～NNW

develops as same as in the Aurora area, it shows that the folding structure in the NNE

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～NNW direction is dominant. The dip of the strata is west in appearance and the

strata is generally overturned.

Though alteration accompanied with mineralization is observed in several

places, all of them were small scale and the zones were limited.

Geochemical anomaly zones of alteration index are outlined in part of the

northwestern district of the Rancho Viejo area by geochemical survey.

Considering the above facts, the north of Capire district, the Santiago Salinas

district and La Campana district in the Aurora area, are considered to be the

prospective zones for ore deposit (shown in figure 1-5-1), since those districts have

thick distribution of hanging wall, geochemical anomaly and remarkable ore showing.

Although the distribution of the horizon of massive sulfide ore deposit and the

hanging wall were developed in Rancho Viejo area, ore showing and marked

geochemical anomaly are rarely observed. Consequently, the potential for ore deposit is

considered to be small in the Rancho Viejo area.

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Chapter 2 Recommendation for the Third Year’s Program

The distribution of sedimentary rocks related with massive sulphide deposits

(Capire deposit, Aurora deposit, etc.), ore showings, alteration zone and these

relationships have been revealed by the second year’s program. Distribution pattern of

specific elements that indicate mineralization and geochemical characteristics in the

surveyed area was outlined by geochemical survey.

The previous exploration data that was obtained in this survey, showed the

existence of unexplored districts such as Santiago Salinas, La Campana and north of

Capire deposit districts.

Massive sulfide type mineralization is expected in Santiago Salinas district

where is underlain by hanging wall sediments and alteration occurred in footwall

dacite accompanying mineralization (Ba:1%).

There is little previous exploration in La Campana district located in the west

of Manto Rico deposit, due to private mining concession. But, this survey has defined

geochemical anomaly, ore showings and ore horizon in the district. Moreover, Drilling

hole MJZC-2 encountered footwall alteration and mineralization which are correspond

to the exposure in the creek situated to the west of Otates. Therefore, Massive sulfide

ore body is expected in the depth of 200-300m below the surface between Manto Rico

deposit and La Campana.

Exploration program must be advanced in north of Capire deposit district

where exhibits geochemical anomaly and alteration zone, and is expected the

continuation of mineralization intersected hole TN-14. Since the previous drilling did

not confirm the ore horizon below thick sedimentary rocks, the deep drilling program is

desirable.

As mentioned above, farther investigations must be recommended in the

followings prospective districts to confirm continuation of mineralization and ore

horizon.

1. Santiago Salinas district

2. La Campana district

3. North of Capire deposit district

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Reference

Campa, M. F (1978): La evolución tectónica de Tierra Caliente, Gro.: Bol. Soc. Geol.

Mex., Ⅳ Convención Geológica, Tomo XXXⅣ,No 2.

Campa, M. F., Campos, M., Flores, R. y Oviedo, R. (1974): La secuencia mesozoica

volcano-sedimentaria metamorfizada de Ixtapan de la Sal, México-Teloloapan,

Guerrero. : Bolétin de la Sociedad Geológica. Mexicana: v.35, p.7-28.

Campa, M. F. y Ramirez., J. (1979): La evolución geológica y la metalogénesis del

noroccidente de Guerrero: Univesidad. Autónoma de Guerrero, Serie

Técnico-Científica: núm.1, p.1-84.

Coney, P.J. y Campa, M. F. (1987): Lithotectonic terrane map of Mexico(west of the 91st.

meridian): US Geological Survey, Miscellaneous Field Studies Map

MF-1874-D.

De Cserna, Z. (1965): Reconocimiento geológico de la Sierra Madre del Sur de México

entre Chilpancingo y Acapulco, Estado de Guerrero: Universidad Nacional

Autónoma de México. Inst. Geol., Boletín: v.62, 76p.

De Cserna, Z. (1978): Notas sobre la geología de la región comprendida entre Iguala,

Ciudad Altamirano y Temascaltepec, Estado de Guerrero y México, D.F.:

Sociedad Geológica Mexicana, Libro guía de la excursión geológica a Tierra

Caliente: p.1-25.

De Cserna, Z. (1983): Hoja Tejupilco 14Q-g(9), con Resumen de la geología de la Hoja

Tejupilco, estados de Guerrero, México y Michoacán: Universidad Nacional

Autónoma de México, Instituto de Geología, Carta Geologíca de Mexico,

Serie de 1:100,000, mapa con texto explicativo: 28p.

De Cserna, Z., Palacions, N. y Pantoja, A. (1978): Relaciones de facies de las rocas

cretácicas en el noroeste de Guerrero y en áreas colindantes de México y

Michoacán: Universidad Nacional Autónoma de México. Inst. Geol., Revista:

v.2, p.8-18.

Elías-Herrera, Mariano y Sánchez-Zavala, J.L. (1992): Relaciones

tectonoestratigráficas del terreno Guerrero en la porcíon suroccidental del

estado de México y su interpretaíon geodinámica: Sociedad Geológica

－178－

Méxicana, XI Convencíon Geológica Nacional, Veracruz, Ver.,

Resúmenes(abstract).

Fries, C. (1960): Geología del estado de Morelos y de partes adyacentes de México y

Guerrero, regíon central meridional de México: Univ. Nacional Autónoma de

México, Inst. Geol., Bolétin: v.60, 236p.

Guerrero, M., Ramirez, J. y Talavera., O. (1990): Estudio estratigrafico del arco volcanico

cretácico inferior de Teloloapan. Guerrero: Abstracts, X Convencion Sociedad

Geológica Mexicana: p.67.

Guerrero, M., Ramirez, J., Talavera., O. y Campa, M.F. (1991): El desarrollo carbonatado

del cretácico inferior asociad al arco de Teloloapan, Norocidente del Estado

Guerrero: Abstracts, Convencion Sobre la Evolucion Sociedad Mexicana de

Mineralogia and Instituto de Geología, Universidad Nacional Autónoma de

México:p.67.

Ishikawa, Y., Sawaguti, T., Iwaya, S., Horiuti, M.(1976):Aproch to exprolation indicator

using footwall dacite lava of Kuroko deposit, trace for alteration haro around

Fukazawa main and volcanic activity, Mining Geology(in japanese).26(2)

JICA・ MMAJ(1994): Reporte sobre la geologia y depositos minerales en la region de

Tejupilco, Estados Unidos Mexicanos. p44

Ochoa Camarillo, H., Gomez-Moreno, V. y Leon Matz, A. (1985): Geología, geoquimica

de mercurio y magnetometria terrestre del area Azulaquez, Gro.: Informe de

Avance, GFE, CRM, Inedito.

Raiz, Erwin(1959): Landforms of Mexico, Cambridge,Mass

Reyes J.S.(1990): Prospeccion geologico-minera del area la Trinidad, Mpio, de

Zacualpan, Mex. CRM.

Sakai, H., Hisamatu, Y. (1996): Stable isotope geochemistry, University of Tokyo Press

Sedlock, R.L., Ortega, G.F., and Speed, R.C. (1993): Tectonostartigraphic terranes and

tectonic evolution of Mexico: Geological Society of America Bulletin: v.100,

p.274-281.

Serratos,R.V., Diaz, A. S,. and Martinez, M. A. (1999): Carta Geológico-Minera,

Teloloapan E14-A77.

－179－

Serratos,R.V., Diaz, A. S,. Trjillo, D. A,. and Martinez, M. A. (1999): Carta

Geológico-Minera, Pilcaya E14-A67.

Serratos,R.V.,et al(2000): Carta Geológico-Minera, Amatepec E14-A66.