field report on khewra gorge and it,s surrounding areas

7/23/2019 Field Report on Khewra Gorge and It,s Surrounding Areas

1/93


2/93


3/93

ContentsCERTIFICATE

ACKNOWLWDGEMENT

ABSTRACT

Chapter-1 ............................................................................................................................................ 13

INTRODUCTION ................................................................................................................................. 13

1.1. Aim Of Study: ........................................................................................................................... 13

1.2. Introducton To The Mapped Area ........................................................................................... 13

1.3. Accessability Of The Mapped Area .......................................................................................... 13

1.3.1 The Salt Range .................................................................................................................... 13

1.3.2. Khewra Town .................................................................................................................... 14

1.3.3. Khewra salt Mine .............................................................................................................. 14

1.3.4 .Stay at Choa Saidunshah ................................................................................................... 15

1.3 Inhabitate Of The Assigned Area .............................................................................................. 16

1.4.Previous Work ........................................................................................................................... 16

Chapter- 2........................................................................................................................................... 18

PHYSIOGRAPHY.................................................................................................................................... 18

2.1. Relief.................................................................................................................................... 18

2.2. Climate .................................................................................................................................... 18

2.3.Vegetation Cover .................................................................................................................. 18

2.4. Weathering............................................................................................................................... 19

2.4.1. Mechanical Weathering .................................................................................................... 19

2.4.2.Frost Action ........................................................................................................................ 20

2.4.3. Chemical Weathering ........................................................................................................ 20

2.5. Hydrology ................................................................................................................................. 212.5.1.Ratna Nala .......................................................................................................................... 21

2.6.Stream Load .............................................................................................................................. 22

2.7.Drainage Pattern ....................................................................................................................... 22

2.7.1.Dendritic Drainage Pattern .................................................................................................... 22

2.7.2.Sub Parallel Drainage Pattern ............................................................................................ 22

2.8. Mass Wasting ...................................................................................................................... 22


4/93

2.9. Main Khewra Nala .................................................................................................................... 23

2.9.1.Bifurcaton Ratio Of Main Khewra Nala: ............................................................................. 23

2.10..Choa Saidan Shah Pidh Nala ................................................................................................ 26

2.10.1.Bifurcaton Ratio Of Choa Saidan Shah-Pidh Nala: ........................................................... 26

Chapter- 3........................................................................................................................................... 29

STRATIGRAPHY..................................................................................................................................... 29

3.1 Introduction .............................................................................................................................. 29

STRATIGRAPHIC TABLE OF THE ASSIGNED AREA.......................................................................... 30

Table 3.1: Stratigraphic succession of Eastern Salt Range (Khewra Gorge) ............................... 30

3.2. Stratigraphy .............................................................................................................................. 31

3.2.1 Salt Range Formation ............................................................................................................. 31

3.2.2 Khewra Sandstone ................................................................................................................. 33

3.2.3. Kussak Formation .................................................................................................................. 36

3.2.4. Jutana Formation .................................................................................................................. 38

3.2.5. Baghanwala Formation ......................................................................................................... 40

3.2.6 Tobra Formation .................................................................................................................... 42

3.2.7.Dandot Formation .................................................................................................................. 44

3.2.8. Warchha Sandstone .............................................................................................................. 46

3.2.9. Namal Formation .................................................................................................................. 48

3.2.10 Sakesar Limestone ............................................................................................................... 50

Chapter- 4........................................................................................................................................... 54

SEDIMENTARY STRUCTURES.................................................................................................................. 54

4.1. Cross Bedding:- ........................................................................................................................ 55

4.2. Ripple Marks:- .......................................................................................................................... 56

4.3. Worm Tracks:- .......................................................................................................................... 57

4.4. Nodule Structures: ................................................................................................................... 58

4.5. Salt Pseudomorphs:- ................................................................................................................ 59

4.6. Karen Structures:- .................................................................................................................... 60

Chapter- 5........................................................................................................................................... 61

DEPOSI'I'IONAL ENVIRONMENTS............................................................................................................. 61

5.1. Salt Range Formation ............................................................................................................... 61

5.2. Khewra Sandstone ................................................................................................................... 62

5.3. Kussak Formation ..................................................................................................................... 62


5/93

5.4. Jutana Formation ..................................................................................................................... 63

5.5. Baghanwala Formation ............................................................................................................ 64

5.6. Tobra Formation ...................................................................................................................... 64

5.7. Warcha Sandstone ................................................................................................................... 65

5.8.Namal Formation ...................................................................................................................... 665.9. Sakaser Limestone ................................................................................................................... 66

Chapter- 6........................................................................................................................................... 67

GEOLOGICAL STRUCTURES..................................................................................................................... 67

6.1. Faults: ....................................................................................................................................... 67

6.1.1.Reverse Fault: .................................................................................................................... 67

6.1.2. Normal Fault ..................................................................................................................... 67

6.1.3. Grangul Thrust fault: ......................................................................................................... 67

6.2. Unconformaties: ...................................................................................................................... 67

6.2.1. Disconformity: .................................................................................................................. 68

6.2.2. Permian unconformity ..................................................................................................... 68

6.2.3. Unconformity ................................................................................................................... 68

6.2.4. Pidh Graben...................................................................................................................... 68

Chapter- 7........................................................................................................................................... 69

HYDRO CARBON POTENTIAL OF THE MAPPED AREA.................................................................................. 69

7.1.Introduction .............................................................................................................................. 69

7.2.Energy Resources ...................................................................................................................... 69

7.2.1.Petroleum Play ................................................................................................................... 69

Table 7.1 :Source Rocks ,Reservoir Rocks and Seal Rocks distribution in the Stratigraphy

Column of the Assigned area along with possible timing of hydrocarbon maturation and

Formation of the traps. ............................................................................................................... 70

7.3. Source Rocks ....................................................................................................................... 70

Maturation ............................................................................................................................... 72

Gene ra tio n an d Mi gr at io n ................................................................................................... 72

7.4. Reserv oi r Rocks ..................................................................................................................... 73

Traps and Seal s ........................................................................................................................ 74

Chapter- 8........................................................................................................................................... 75

ECONOMIC GEOLOGY............................................................................................................................. 75

8.1. Introduction ............................................................................................................................. 75


6/93

8.2.Coal ........................................................................................................................................... 75

8.3.Economic Industrial Raw Materials and Minerals .................................................................... 76

8.3.1. Rock Salt ............................................................................................................................ 76

8.3.2. Gypsum ............................................................................................................................. 77

8.3.3. Limestone .......................................................................................................................... 788.3.4. Dolomite............................................................................................................................ 80

8.3.5. Sandstone ......................................................................................................................... 80

Chapter- 9........................................................................................................................................... 82

REFERENCES.......................................................................................................................................... 82


7/93


8/93


9/93


10/93

All Praise To All Mighty ALLAH Who Gave Us Knowledge ,Education And

Learning To Work To The Best Of Our Abilities, Courage And Patience To Obligation .We

Are Able To Complete Our Field Work And Are Eventually Presenting This Field Report. We

Are Thankful To Dr Ibrahim Baloch Chairman ,Geology Department , And Also Our

Supervisor For Organizing The Field Program , Which Was Not Possible Without Him..We

Offer Our Sincere Thanks To Assistant Prof.Mr. Rahum-U-Din, Assistant Prof. Ahmed Shah

Kakar And Last Not Least Assistant Prof. Syed Haroon Ali For Their Supervision In Field And

Gaudiness For Preparation Of This Field Report . We Had Some Difficulties In Doing This

Task ,But They Taught Us Patiently Until We Knew What To Do .

Last But Not Least ,Our Group Who Were Doing This Field Work Sharing Ideas ,Helping

Each Other And We Combined And Discussed Together ,We Had This Task Done.


11/93


12/93

A comprehensive geological Map of Khewra Gorge and its surroundings

area Jhelum and Chakwal districts of Punjab Province, Which is prepared on the scale of

1:50000 about 60 square Kilometer area was mapped which was lying on latitude 30o

43/

04//

to 32o

38/

48//

and longitude of 73o

00/

25//

to 72o

59/

21//

and the Toposheet No 43

D/14 of Geological Survey of Pakistan.

This report describes the stratigraphy Structural geology, economic Geology and geological

history of the studied area. The rock units in studied area range from Precambrian to the

Eocene age. The Stratigraphic Succession of the area: Salt Range Formation (Pre-

Cambrian), Khewra Sandstone (Early Cambrian), Kussak Formation (Early Cambrian), Jutana

formation (Middle Cambrian), Baghanwala Formation (Late Cambrian) Tobra formation

(Early Permian) Dandot Formation (Early Permian) Warcha Sandstone (late Permian) Namal

Formation (Early Eocene) and Sakesar Limestone (Early Eocene) Detail study of Stratigraphy

of the area is carried out including the Characters of each rock unit. Shale , Limestone,

Sandstone and marls the major Lithologies of Sedimentary rocks.

These formations were deposits under shallow to moderately deep marine and fluvial and

glacial environments. The assigned area tectonically active and the rocks units thruster

over Punjab plain and highly deformed.

Geological Cross section were prepared for better understanding of the structures of the

assigned area along with their symbols and abbreviations also studied the potential

hydrocarbons of the rocks and economic rocks of the area.


13/93

Chapter-1

INTRODUCTION1.1. Aim Of Study:

The geological Fieldwork and thesis writing is an essential Requirement for Ms.c degree in

Geology .Students of Ms.c (Final) have done field work for three weeks in the Eastern Salt

Range Around Khewra Gorge in the Jhelum Chakwal district of Punjab Province, Which

was carried out In the month of February-March 2012 .

The main purpose of field work was to learn the geological mapping, recognition of the

geological feature ,proper collection of geological data in the field work and with student

point of view they are trained for all sort of geological structures ,tectonics and

stratigraphy of the mapped area observed in field .

1.2. Introducton To The Mapped Area

The area around the vicinity of Khewra gorge to Choa saiden shah (Jhelum district) was our

assigned area, which lies in eastern part of salt range, Pakistan. The area is covered in

Toposheet no 43D/14 of the survey of Pakistan .The location of the salt range is such that

the potwar plateau lies in its north ,Punjab plain is In south ,while in the east and west .it is

bounded by Jhelum and Indus rivers ,respectively.

1.3. Accessability Of The Mapped Area

1.3.1 The Salt Range

Most of the tourists to the Punjab tend to follow the beaten track .they go to well known

places with developed infrastructures of accommodation and other facilities .among the

places ,which one tends to over look ,is Jhelum , the recruiting ground of the former British

Army and now to Pakistan Army .It is also the starting point of the famous salt Range ,a

name given to two lines of low rugged hills and the fertile land sandwiched between them.


14/93

FIG 1.1 Map is showing Location of the Field Area.

1.3.2. Khewra Town

Khewra is a town of Pind Dadan Khan Tehsil in Jhelum District, Punjab province,

Pakistan.the population of Khewra is 1,00.000 and the world second largest salt deposits

are located in Khewra .

1.3.3. Khewra salt Mine

The Khewra salt mine also known as Mayo Salt mine named in the honor of Lord Mayo, who visited

the mine as Viceroy of IndiaThe salt mine is a part of salt range originated about 800 million years


15/93

ago after a shallow sea evaporated and following geological movements salt range

stretched to about 300 kilometers was formed It is said that the salt reserves at Khewra

were discovered when Alexander visited South Asia, coming across the Jhelum and

Mianwali region, during his Indian campaign. The discovery of the mine, however, was not

made by Alexander nor his "allies", but by his horse. It is stated that when Alexander's

army stopped here for rest, the horses started licking the stones. One of his soldiers took

notice of it and when he tasted the rock stone, it was salty thus leading to the discovery of

the salt mine. During Mughal era the salt was made available commercially by exporting it

to different markets including far away region of Central Asia With the downfall of Mughal

empire, the mine was taken over by Sikhs. Hari Singh Nalwa the Sikh ruler shared the

management of mine with the ruler of Jammu and Kashmir, Gulab Singh. The salt quarried

during Sikh rule was not only a source of general consumption but also a source of revenue

After Britishers took over the territory from Sikhs, they developed the mine further in

1872. Britishers found the mining carried out in an inefficient way with irregular and

narrow tunnels, entrances, which made the movement of laborers dangerous and difficult.

The supply of water inside mine was poor and there was no storage facility for the mined

salt. The only road to Khewra mine was a rocky road on difficult terrain. Addressing these

problems the then government leveled the road, built go-downs, provided supply of water,

improved the entrances and tunnels, introduced better mechanism for excavation of salt.

1.3.4 .Stay at Choa Saidunshah

Our stay during the field work was in a small town and Union Council of Chakwal District in

the Punjab Province of Pakistan. It is the one of the seven Union Councils of Choa Saidan

Shah Tehsil

This town is named after the saint Saidan Shah Shirazi. The legend goes that the area was a

desert until the holy man arrived, when he struck the ground with his staff and sweet

water sprang up ("Choa" means "spring"). The saints shrine is set back from the main

bazaar in a courtyard, and the annual urs is held in April.

Choa Saidan Shah is located in the south of Chakwal about 35 kilometres (22 mi) from the

town centre on the Chakwal-Khewra road, in the east of Kallar Kahar, about 27 kilometres


16/93

(17 mi) from the M2 motorway, about 10 kilometres (6 mi) north of Khewra and about 6

kilometres (4 mi) from Katas.The town is placed in a bowl shaped valley, surrounded by

hills. It is surrounded by trees and orchards, and is famous for its roses and perfumes.

1.3 Inhabitate Of The Assigned Area

The study area false administratively within Jhelum-chakwal District and most of its

population live in small towns Khewra .Tobar Village Choa Saidanshah,Dandot Village and

Pidh village are the major localities where most of the population of mapped area

habitats.khewra and choa Saidanshah are generally more populated . All agricultural

activities are confined to the big plains which run parallel in between the mountains .

Rain water is generally used for irrigation in addition to tube wells,which are also the

major source of irrigation particularly in valleys and depressions.

1.4.Previous Work

In the past the salt Range has attracted geologists from all over the world to study

Cambrian Stratigraphy .the Permian Triassic boundary,and Lower Territary foraminiferal

biostratigraphy .Particular note is the pioneering work of E.E.GEE(1935,1945) ,who

dedicated almost his entire geological career to study of the Salt Range .His initial work

related to solving the controversy regarding the age of the Saline Series,a burning Topicof that time ,and he made a great contribution by producing a geological map (more

recently six sheets on a scale 1:50,000 have been published by the Geological Survey of

Pakistan excluding the Trans-Indus Surghar Range).

DAVIES and PINFOLD (1937) completed a comprehensive study of Lower Teritary Larger

foraminifera of the Salt Range.WAAGEN (1882-1885,1895) worked on the brachiopods of

the permian of the Salt Range and FATIMI (1973) studied the ceratitids of the Triassic of

the Salt Range and Trans-Indus Surghar Range.He also worked on stratigraphic

nomenclature on the Salt Range as did SHAH (1977).KUMMEL and TELCHERT (1966,1970)

illustrated Permian brachiopods and described the detailed stratigraphy of the Permian

rocks while GRANT (1966)described trilobites.HAQUE (1956) described the amaller

foraminifera from the Teritiary formations of the western Namal Gorge ,Salt Range .AFZAL

(1997) completed his doctoral thesis on the planktonic foraminifera of the paleogene and


17/93

established a planktonic biostratigraphy for the patala formation of the Salt Range and

Surgher Range (AFZAL and VON DANIELS ,1991;AFZAL and BUTT ,2000). SAMEENI(1997)

completed his doctoral thesis on paleogene biostratigraphy of the Salt Range under

UNESCO IGCP-286 , headed by Prof .Lukas HOTTINGER o Basal University , Switzerland ,and

established an alveolinid biostratigraphy for the Eocene succession of the Salt Range

(SAMENI and BUTT ,1996,2004;SAMEENI and HOTTINGER , 2003).


18/93

Chapter- 2

PHYSIOGRAPHY

2.1. Relief

The Mapped Area lies between the Eastern Plateau in southeast and the Potwar

Plateau in north. The highest elevation from sea level is 3687 feet and is called

Tobra Peak . . The lowest elevation from sea level is I500 near Khewra town in south

of the Mapped Area. Thus the absolute reliefis 1987 feet.

2.2. Climate

The Mapped Area lies within the semi arid region. The local climate is more towards the

humid because the area experienced more rainfall than the adjacent areas of

Potwar, Kussak and Khewra.

Thick cover of vegetation reduces the intensity of hot summers. The altitude has

significant effect which produced precipitous slopes against the Monsoons.

2.3. Vegetation Cover

Dense vegetation cover conceals the geology of certain parts of the area .Two rakhs

(jungles) are present in the Project area These are Rak.h Karangal and Rak.h

Drengan. These rakhs presented serious difficulties in traversing and geological studies.

In Southern part, the south facing slopes are generally warmer than adjacent north facing

slopes due to direct fall of sunrays. At lower latitudes these sunny slopes are unable to

preserve moisture content. The nearby north facing slopes retain moisture content and

hence better vegetation cover is there. (Plants and Ecosystems by W.D. Billing).

The names of various herbs, shrubs and trees present in the area are as follow:

Oleacuspidata (Kaoo)

Acacia modesta (Phulai) Acacia arabica (Kiker)


19/93

Capparis dicidua (Kundair) Dodonea viscosa (Snutha) Ipomea viscosa (Bhaikar) Gnmda Saghar Dhaman Gogair

2.4. Weathering

Weathering is the total effect of all the various sub aerial processes that cooperate in

bringing about the decay and disintegration of the rocks. Weathering of rocks depends

upon following factors:

Mineral composition and structure of the rock Climatic conditions Presence and absence of vegetation Topography of the area Weathering is of three types Mechanical or Physical Weathering Chemical Weathering Biological Weathering

2.4.1. Mechanical Weathering

Mechanical changes may be brought about by changes in the temperature of the rock body

itself or it may be due to the Formation of ice within the interstices or within the joints of

the rock.

mechanical weathering break up rocks into smaller and smaller fragments by physical

forces without involving appreciable chemical decomposition.


20/93

In the Mapped Area following processes of mechanical weathering could be observed.

2.4.2.Frost Action

Mechanical disintegration of rocks depends to a large degree upon the presence of water

in the interstices or joints. Rocks are disintegrated by repeated freezing and thawing of

water in these joints and voids etc.

Water fills the crevices and joints present in the rocks, on fall of temperature it freezes and

expands because of increase in volume. This volume increase exerts a lot of pressure upon

the sides of joints and voids. Repeated freezing and thawing resulted in the shattering of

rock into angular fragments. These angular fragments can be seen on the slopes formed by

sandstone and limestone etc, in Tobra upper portion of gorge and Pind saiden shah.

2.4.3. Chemical Weathering

The Mapped Area is predominantly covered by Sakaser Limestone ,Khewra sand stone

,salt range Formation ,Namal and Warcha .Main type of chemical weathering active in

these carbonate rocks is solution weathering.

Rain water with dissolved carbon dioxide together with humus acid from the surface of

rocks attacks the carbonate rocks and removes them in the form of solution.

Following evidences of solution weathering are reported from the Mapped Area.

Karen structuresMiniature ridges formed on the surface of Sakesar Limestone.Karen structures are

also present in salt of salt range Formation.

Solution cavitiesSolution cavities in the Sakesar Limestone exposed and Namal Formation.

Widened jointsIn Sakesar Limestone, Khewra sand stone ,warcha sand stone and Jutana Formation, joints

are widened due to solutioning.


21/93

Honey comb weatheringIt is present in Khewra sand stone in Khewra Gorge..

Plant WedgingWith the growth of plants and their roots, joints and crevices are extended due to which

rocks become loose. Plant wedging effect in the Mapped Area is noted from roots of

banyan tree.

2.5. Hydrology

The area is drained by two permanent and a lot of aphermal streams. Permanent source of

water are springs of fresh water suggesting shallow reservoir rocks.

The parental streams are;

2.5.1.Ratna Nala

A Nala flowing in front of Karangal Ridge between the "Sarai" and Karangal Peak (3511).

Springs are the permanent source of water. All the streams reduced in volume during

winter. Springs were observed in Ratna Nala.

Numerous wells have been dug through the Wahali valley and Basharat area to

irrigate cultivated land. Ground water level is very low during dry season. A number of

water ponds are present. Rainwater is stored by building small bunds around the ponds.

All the streams of the Mapped Area drain into "Kus Surar" which joins the River

Bunha. Karangal Ridge extending north or northeast, Wahali Section extending eastwest

and Chail Ridge striking northeast act as water divide.

Locals have built protective bunds to save their cultivated land from erosion in rainy

seasons.


22/93

2.6.Stream Load

The load carried by streams at higher altitude is composed of large boulders and angular

fragments of rocks whereas in main streams at lower level, the load mainly is pebbles, gravels and

silty sand etc.

2.7.Drainage Pattern

In the Mapped Area, two types of drainage pattern have been observed. Dendritic drainage pattern

developed in northeastern half of the area. Fig 2.1

Subparallel drainage pattern developed on the dip slopes of Sakaser Limestone around the

saidan shah and pidh area . Fig 2.1

2.7.1.Dendritic Drainage Pattern

This type of drainage pattern is characterized by irregular branching of the tributaries in

many directions and at almost any angle usually less than right angle. This type of drainage

pattern is developed on the rocks of uniform resistance and structurally non controlled

rocks.

In the Mapped Area special dendritic pattern, the pinnate drainage pattern is observed.

The tributaries are sub parallel to the main stream and join it at acute angles. This

effect is particularly due to steep slopes on which the tributaries developed streams inKarangal area and Choa Ganj Ali Shah area.

2.7.2.Sub Parallel Drainage Pattern

Sub parallel drainage pattern is an intermediate type between dendritic and parallel drainage

patterns. It may develop on steep slopes because run off find the shortest line in parallel

streamlets, perpendicular to the strike of scarp. Nearly parallel tributaries join the main stream at

an angle.

In Wahali Section ofthe Mapped Area, the streams flowing at ihe dip slope ofSakaser Limestone

exhibit this type of drainage pattern.

2.8. Mass Wasting

Due to effect of physical and chemical weathering rocks become weak and produce loose

material. The down slope movement of loose material purely under gravity is termed as


23/93

mass wasting. The results of following processes of mass wasting were observed in the

area.This mass wasting is well observed in salt range Formation.

Rock CreepThe down slope movement of the individual rock blocks is called rock creep.

In Jutana Formation, Khewra Sandstone and Sakaser Limestone of the Mapped Area, mass

movement of this type is observed in Karangal area as well as along the Chail Ridge.

Debris SlideDebris slides are common in Sakesar Limestone, Jutana Formation and Khewra Sandstone.

Rock debris fall dov..n along slopes in rolling motion under the influence of gravity.

2.9. Main Khewra Nala

The drainage pattern in the mapped area is dendritic drainage pattern .this drainage

pattern was developed along the anticlinical axes of the Khewra anticlines .the drainage

was developed after the deFormation of the anticline.the Khewra gorge which denotes the

main stream in the area is basically the anticlinal axis of the Khewra anticline but after

faulting and deFormation the present day drainage pattern was developed. the main

stream in the area is MAIN Khewra NALA.

In this drainage pattern water flows from upper northern area to down ward in to the main

Khewra nala towards the south.

The bifurcation ratio (Rb) for main Khewra nala is determined such as:

2.9.1.Bifurcaton Ratio Of Main Khewra Nala:

STREAM ORDER VALUES

Stream of 1st

order (a) 50


24/93

Stream of 2nd

order (b) 16

Stream of 3rd

order (c) 4

Stream of 4th

order (d) 1

FORMULA USED

Stream of 1st

order (a) +Stream of 2nd

order (b) +Stream of 3rd

order (c)

Rb= Stream of 2nd

order (b)+ Stream of 3rd

order (c)+ Stream of 4th

order (d)

Mean

OR

By putting the values

Rb = 50/16 + 16/4 + 4/1

64

3

Rb = 200+256+256

a + b + c

b c d

Rb= Mean


25/93

64

3

Rb =11.25 = 3.7

3

Bifurcation ration of the main Khewra nala is 3.7.


26/93

2.10..Choa Saidan Shah Pidh Nala

This drainage pattern is of sub-parallel type .different large and small scale tributaries were

connected near choa-saidan shah city and around pidh area .

Here the channels of the water were less as compare to gorge nala.

2.10.1.Bifurcaton Ratio Of Choa Saidan Shah-Pidh Nala:

STREAM ORDER VALUES

Stream of 1st

order (a) 20

Stream of 2nd

order (b) 6

Stream of 3rd

order (c) 2

Stream of 4th

order (d) 1

FORMULA USED

Stream of 1st

order (a) +Stream of 2nd

order (b) +Stream of 3rd

order (c)

Rb= Stream of 2nd

order (b)+ Stream of 3rd

order (c)+ Stream of 4th

order (d)

Mean

OR


27/93

By putting the values

Rb = 20/6 + 6/2 + 2/1

6

3

Rb = 20+18+12

6

3

Rb =8.33 = 2.7

3

Bifurcation ration of the Choa saidan Shah Pidh Nala is 2.7.

a + b + c

b c d

Rb= Mean


28/93

FIG 2.1


29/93

Chapter- 3

STRATIGRAPHY

3.1 Introduction

In the assigned area ,the rocks are mainly of sedimentary origin, ranging from pre

Cambrian to Eocene

The rock units exposed in the mapped area are as follow:

Recent to Sub Recent alluvium Early Eocene Sakesar Limestone Early Eocene Namal Formation Unconformity Early Permian Warchha Sandstone Early Permian Dandot Formation Early Permian Tobra Formation Unconformity Late Cambrian Baghanwala Formation Middle Cambrian Jutana Formation Early Cambrian Kussak Formation Early Cambrian Khewra Sandstone precambrian Salt Range Formationin Nilawahan group sardhi Formation is absent.

There are three unconformities .there is unconformity between Khewra sand stone and

kussak Formation and a well known major unconformity present between Cambrian

and Permian period , and the third unconformity is present between warcha sand stone

and Namal Formation .

The stratigraphic table is shown below .


30/93

STRATIGRAPHIC TABLE OF THE ASSIGNED AREA

Table 3.1: Stratigraphic succession of Eastern Salt Range (Khewra

Gorge)

No. Age. Formation. Lithology.

10. Early Eocene Sakesar Limestone Massive and Nodular Limestones, with Marls ,

Chert in upper part

9. Early Eocene Namal Formation Light Gray Calcareous Shales and Limestones

Unconformity

8. Early Permian Warcha Sandstone Red and Light Colored Sandstones and Grits ,in

part Arkosic, Clay Interbeds

7. Early Permian Dandot Formation Olive green and Gray Sandstones and Shales ,

occasionally Carbonaceous

6. Early Permian Tobra Formation Conglomeratic Sandstones and Shales, Boulders

mainly Igneous or Metamorphic

Unconformity

5. Late Cambrian Baghanwala Formation Blood Red Shales and Flaggy Sandstones


31/93

3.2. Stratigraphy

3.2.1 Salt Range Formation

Nomenclature and Type Locality

The term Salt Range Formation has been introduced by Asrarullah (1962) after the

Salt Range in the Punjab Province. Previously it was named as "Saline Series by Wynne

(1878) and Punjab Saline Series by Gee (1945). Khewra Gorge (lat. 3240N; long.

730030 E) in the Eastern Salt Range, Jhelum district, Punjab Province, has been

designated as the type section (Shah,1977).

Lithology

In the Mapped Area the Formation is composed of gypseous marl in the lower part .The

marl is massive and includes gypsum, dolomite and clay. Quartz crystals of variable sizes

are also present in this marl. It is white to light grey in color. It is massive and is associated

with bluish grey clay. The dolomite is light in color. It is flaggy and cherty in nature. It is

associated with dolomitic shales, bituminous shales. The oil shales when freshly broken

give off oily smell. Oil shales are of dark brown color and weathering color is very dark.

There are elongated nodules containing bituminous material. They show cavities filled with

calcite.

Distribution and Thickness

Salt Range Formation is widely distributed in the southern parts of the area, but it is only

restricted in the nalas. Its thickness was not measured because base of the Formation is

not exposed.

Contacts

Base of the Formation is not exposed anywhere including the study area. The upper

contact with the Khewra Sandstone is transitional.


32/93

Age

The Salt Range Formation is devoid of fossils. Due to its position below Lower Cambrian

sediments and above the metamorphic Precambrian basement, it is considered as Late

Neoproterozoic. This is in accordance with the results of sulphur-isotope measurementscarried out on gypsum samples from the top of Salt Range Formation which indicate an age

of about 600 m.y. (H.A. RAZA)

FIG 3.1 :

Field Photograph Showing Salt Range Formation in the Khewera Gorge at

(Long 73o

00/

11//

, Lat 32o

39/

41//

)


33/93

3.2.2 Khewra Sandstone


The Khewra Group of Noetling (1894) is formalized as Khewra Sandstone after theKhewra town in the Punjab Province. Other terms were "Purple Sandstone Series of

Wynne (1878), "Khewra Group of Noetling (1894) and Purple Sandstone of most

subsequent authors. Khewra Gorge (lat.3240N; long. 7300E) in the Eastern Salt

Range, Jhelum district, PunjabProvince, is designated as the type locality.

Lithology

Khewra Sandstone dominantly consists of sandstone with minor amount of shale. The

basal part consists of thin-bedded, fine to medium-grained sandstone, partly shaly, passing

upward into massive, thick-bedded, purple, occasionally buff-colored, jointed sandstone

with thin bands of clay. Upper part is dominantly reddish brown and yellowish brown

sandstone, becoming pale towards the top. The sandstone is well sorted, cross bedded

and has abundant ripple marks and mud cracks and also shows convolute bedding in the

lower part .

The Khewra Sandstone can be divided into 4 units: (Saqib et. al 2009)

1. The lower unit, often called the Maroon Shale Group, consists of thin bedded, dark red

to brown, argillaceous siltstone, with intercalations of dark purple shales. Occasionally

argillaceous sandstones are present.

2. The middle unit is a thin bedded to flaggy, purple to brick red sandstone. It is generally

micaceous, fine grained and silty at the base; the grain size increases towards the top.

Sedimentary structures like ball and pillow, climbing ripples, parting lineation, tabular and

trough cross bedding are present.

3. The upper unit consists of light red to yellowish white sandstone which is medium hard

to friable. It gets coarser towards the top. Wedge planar cross bedding, large scale trough

cross bedding, honey comb weathering are prominent feature of this.


34/93

4. The topmost unit of the Khewra sandstone is yellowish white, friable, medium grained,

sandstone which shows high percentage of quartz. The sandstone is ferruginous; cross

bedded and contains calcareous lenses.(FIG 3.2)


Khewra Sandstone is widely distributed in the southern parts of the area, but it is only

restricted in the nalas. More than 200 m in Khewra gorge.

Contacts

The contact of Khewra Sandstone with the underlying Salt Range Formation is conformable

and gradational. Its upper contact with Kussak Formation is sharp .

Age

The Khewra Sandstone does not contain well-preserved fossils but possesses evidence

of organic remains and trace fossils which have been interpreted as diggings of

trilobites (Schindewolf and Seilacher, 1955).Because of its position between the Late

Proterozoic Salt Range Formation and the fossiliferous Early Cambrian Kussak Formation,

in the Eastern Salt Range the Khewra Sandstone is thought to represent the basal part of

the Lower Cambrian.(Schmdewalf and seilachaclass)


35/93

FIG 3.2

Field Photograph of Khewera Sandstone in the Khewera Gorge at the

(Long 73o

00/

02//

E and Lat 32o

39/

44//

N)


36/93

3.2.3. Kussak Formation


The "Kussak Group" ofNoetling (1894) is formalized as Kussak Formation after Kussak Fort

in Eastern Salt Range. Obolus or Siphonotreta Beds of Wynne (1878), Neobolus Beds of

Waagan (1884) and Kussak Stage of Pascoe (1959). Kussak Fort eastern Salt Range, District

Jhelum, Punjab.

Lithology

Kussak Formation contains shale with thin bands of glauconitic sandstone. Shale 1s

grey, greenish grey and purplish in color. Sandstone is micaceous.(FIG 3.3)

In the Mapped Area were found greenish grey shales and thinly bedded micaceous

sandstone. In the upper part sandstone becomes calcareous. Ripple marks worm tracks

were observed.

Thickness and Contacts

At type locality it is thick while in Mapped Area its thickness is 10 feet. It is outcropped

along west facing scarp in Khewra gorge.

It has sharp, conformable contact with Khewra Sandstone while upper contact with Jutana

Formation is transitional.

Fossils and Age

The Formation is fossiliferous, especially in the upper part. Schindewolf, Seilacher (1955)

and Pascoe reported following fossils. Neobolus Warthi, Lingulella wanniecka, HyolithesWynni and Redlichia noetlingi. Age of the Formation is Early Cambrian.(Schindewolf and

seilacher 1955)


37/93

FIG 3.3

Field Photograph of Vertical Bioturbation in Kussak Formation along the Choa SaidanShah Road

(Long 72o

53/

21//

E and Lat 32o

41/

01//

N)


38/93

3.2.4. Jutana Formation


The Jutana Group of Noetling (1894) is formalized as Jutana Formation after Jutana Village

in eastern Salt Range.Magnesium Sandstone of Fleming (1852) "Jutana Group" ofNoetling

(1894)".Jutana village, District Jhelum Eastern Salt Range, Punjab Province.

Lithology

Jutana Formation is composed of dolomite, shale and sandstone. In the Mapped Area this

Formation can be divided into three units, lower sandy dolomite, middle shaly portion

(similar to Kussak) and upper pure dolomite characterized by chop board

weathering. (FIG 3.4)


The Formation is widely distributed in southern part ofthe Mapped Area. Typical cliffs of

Jutana Formation can be seen in Khewra gorge.

At type locality the thickness is 240 ft whereas it is 300 feet thick while in Mapped Area it is

about 60 m thick.

The contact with underlying Kussak Formation is transitional and with overlying

Baghanwa!a Formation is sharp.

Fossils and Age

The Formation contains tracks and burrows of Trilobite. Early Cambrian or Early Middle

Cambrian age is assigned to the Formation on the basis of faunal record.(Techert 1964)


39/93

FIG 3.4

Field Photograph of Jutana Formation showing the thick beds of dolomites along Choa

Saidan Shah road at ( Long 72o

53/

25//

E and Lot 32o

41/

12//

N)


40/93

3.2.5. Baghanwala Formation


Baghanwala Group of Noetling (1894) is formalized as Baghanwala Formation after the

villageBaghanwala, Jhelum districPunjab Province.Wynne (1878) named as

Pseudomorphic Salt Crystal Zone. Holland (1926) called it Salt Pseudomorphic Beds.

Pascoe (1959) "Baghanwala Stage". Baghanwala village Eastern Salt Range, Jhelum District.

Lithology

It is composed of claystone,. Mud stone , Siltstone and thin bedded flaggy sandstone. The

flags are purple, grey or blue green. Primary sedimentary structures such as wave ripple

marks and mud cracks are present. Mud stone to silt stone (Upper lower part) are in blood

red color and characterized by pseudomorphic casts of salt crystals along the bedding

planes.(FIG 3.5 )

Presence of salt pseudomorphs, wave ripple marks mud cracks etc. indicate that Formation

was deposited under lagoonal envirorunent and arid climatic condition.


The Formation is mainly developed in Eastern Salt Range. Good exposures of Baghanwala

Formation can be seen in the Mapped Area.

At type locality the Formation is 300-350 feet thick. In the Mapped Area, the thickness is

20 feet due to erosion. The upper contact with Tobra Formation is unconformable

whereas lower contact is conformable with Jutana Formation.

Fossils and Age

No fossil record and Formation is Middle Cambrian in age.


41/93

FIG 3.5

Field Photograph showing Thin interbedded of sandstone and shale of Baghanwala

Formation at (Long 72o

49/

13//

E and Lat 32o

30/

21//

N)


42/93

3.2.6 Tobra Formation


The term Tobra Formation has been introduced by Gee (written communication, 1964),for the lowest unit of the Nilawahan Group. "Talchir Series" of Blanford (1856),

"Talchir Conglomerate", "Talchir Stage" of Gee (in Pascoe, 1959), "Talchir Boulder Beds" of

Pascoe (1959), "Salt Range Boulder Bed" of Teichert (1967) were known in previous

literature. Tobra village (lat.3240N; long. 7250E) Eastern Salt Range, Jhelum district,

Punjab Province

Lithology

The Formation includes following units from base to top

Boulders which are mainly pink granites and grayish quartzite.

Red pebble bedded sandstone.

Grayish cross bedded siltstone

White massive sandstone.

Black shale with grit lenses


It is only present in the southern part of the Mapped Area, along nalas. The Formation has

a thickness of 10m. (FIG 3.6)

Contacts

The lower contact of the Tobra Formation is a widespread unconformity with baghanwala

Formation while The upper contact with the Dandot Formation is (gradational)

conformable. The contact can be recognized with change in lithology from black and

dark brown shale to greenish sandstone of Dandot Formation


43/93

Age

The Tobra Formation contains ostracizes, and fresh water bivalves, pollen, spores,

microplanktons as well as flora remains including Glossopteris and Gangamopteris (Reed

1936). On the basis of fauna the age is considered as Early Permian (Shah, 1977).

FIG 3.6

Field Photograph Showing Contact b/w Tobra Formation and Dandot Formation along

the Choa Saidan Shah Road at (Long 720

45/

21//

E and Lat 32o

30/

21//

N )


44/93

3.2.7.Dandot Formation


The Dandot Group of Noetling (1901 a, b) is formalized as Dandot Formation after the

village Dandot in Eastern Salt Range, Jhelum district, Punjab Province. "Olive Series",

"Conularia Beds", "Erydesma Beds of Wynne (1878), "Speckled Sandstone" of Waagen

(1879), and "Dandot Group" of Noetling (1901) were different names assigned for this

Formation. East of Dandot (lat. 3239N; long. 7258E) Jhelum district, Punjab Province.

The Khewra-Choa Saiden Shah road section is designated as the principal reference section.

Lithology

In the Mapped Area the lithology consists of light-grey to olive green sandstone with

occasional pebbly beds and subordinate shale Distribution and Thickness.

The Formation is well exposed toward the Dandot village, in the Mapped Area it is not well

exposed. The thickness of this Formation in the mapped area is 12m.(Fig 3.7)

Contacts

The Dandot Formation has a gradational contact with the underlying Tobra Formation. The

upper contact with Warchha Sandstone is conformable and sharp

Fossils

The Formation contains rich fauna of brachiopods, bivalves, gastropods, pteropods,

bryozoans and ostracodes, as well as spores (Kadri, 1995).

Age

On the basis of the stratigraphic position of the Formation above the Tobra Formation, and

the presence of fauna in the Formation, Early Permian age has been assigned. (Telchert

1967)


45/93

FIG 3.7:

Field Photograph Showing Contact b/w Dandot Formation and Warcha Sandstone the

Khewera Gorge at

(Long 72o

59/

49//

E and Lat 32o

33/

21//

N)


46/93

3.2.8. Warchha Sandstone


The name Warchha Sandstone was coined by Hussain (1967), prior to this other terms were

Warchha Group by Noetling (1901) after the Warchha Gorge in the Salt Range in Mianwali

district, Punjab Province. "Middle Speckled Sandstone" of Waagen (1889-91) and "Speckled

Sandstone" of Gee (1945) were also prevalent in literature. The type section of Warchha

Sandstone is Warchha Gorge (lat. 3227N; long. 7158E), in Central Salt Range, Punjab

Province.

Lithology

This Formation consists predominantly of sandstone. The sandstone is red,purple or lighter

shades of pink color. It is medium to coarse-grained and is pebbly, friable and arkosic. The

pebbles are of mostly of pink granite, quartzite and feldspar. The sandstone is thick bedded. It

is highly jointed and is locally speckled. (Fig 3.8)


The Formation is widely distributed in the southern and south western part of the mapped

area. It is mainly present along the nalas; Khewra gorge upper portion of the Khewra scarp.. It is

57m thick in the Mapped Area.

Contacts

The lower contact with Dandot Formation is conformable and sharp. The upper contact with

the Sardhai Formation is transitional which is placed at the top of the highest massive

sandstone.

Fossils

No diagnostic fossils are known from this Formation except from worm- casts and petrified

wood (Fatmi, 1973).


47/93

Age

On the basis of stratigraphic position, Early Permian age has been assigned to this

Formation.(Hussain 1967)

FIG:3.8

Field Photograph Showing Warcha Sandstone in the Khewera Gorge

(Long 72o

49/

59//

E and Lat 32o

33/

21//

N)


48/93

3.2.9. Namal Formation


The "Namal Limestone and Shale" of Gee is formalized as Namal Formation after the Namal

Gorge, in the Western Salt Range, Mianwali district of Punjab Province. Prior to this other terms

were "Namal Limestone and Shale" of Gee (1935), and "Namal Marl" of Danilchik and Shah

(1967). Namal Gorge, Western Salt Range, Punjab province, is type locality of this Formation.

Lithology

In the mapped area, lithology of this Formation consists of limestone in the upper part and marl

below. Limestone and marl is almost is equal parts but marl becomes dominant in the basal

part. The limestone is whitish to medium grey, argillaceous hard, dense, medium to thick

bedded. It is nodular in part. Crystallization of calcite was noted in the joints.

Foraminifera are seen as small whitish specks on the weathered surface. Marl is whitish to

medium grey calcareous claystone which becomes silty at places. (FIG 3.9)


This Formation is widely distributed in the northern part of the Mapped Area. It forms

continuous escarpments. It is 20 -30 m thick in the Mapped Area.

Contacts

The lower contact of Namal Formation is placed at the top of gentle slope formed by underlying

warcha Formation. The contact is conformable with a thin transitional zone of grey marl

and shales. The upper contact with the Sakesar Limestone is conformable, sharp and distinct

Fossils

The Formation contains mollusks and foraminifera. Some important foraminifera include

Nummulites atacicus, N. subatacicus, N. mamillatus, N. irregularis, Assilina granulose, A.

laminosa, A. spinosa, A. subspinosa, A. daviesi, Lockartia tipperi, L. hunti, L. conditi and

Discocyclina ranikotensis (Kazmi and Abbasi, 2008).


49/93

Age

On the basis of the above fauna, Late Paleocene to Eocene age has been assigned to this

Formation.

FIG 3.9

Field Photograph Showing Nodules of LimeStone in the Namal Formation at Choa saidan shah

Road (Long 72o 58/

22//

E and Lat32o 41/

34//

N)


50/93

3.2.10 Sakesar Limestone


The term "Sakesar Limestone" has been introduced by Gee after the peak Sakesar in the

Central Salt Range. Sakesar Peak (lat. 3231'30"N; long. 7136'E), Central Salt Range.

Principal reference section is Bhadrar village (lat. 3241'N; long. 7231'E) in Eastern Salt Range,

Jhelum district, Punjab Province.

Lithology

The Formation consists predominantly of limestone with subordinate marl. The limestone

throughout its extent is cream colored to light grey, nodular, usually massive with

considerable development of chert in the upper part.

In the mapped area, the Sakesar limestone is composed of dense homogeneous limestone

which varies from light grey to dark grey in color. It is massive too thick bedded and is highly

fossiliferous at places. (FIG 3.10)


It is widely distributed in the northern part of the mapped area. It is not measured in the

Mapped Area.

Contacts

The Formation conformably overlies the Namal Formation.

Fossils

The Sakesar Limestone has a sporadic capricious distribution of fossils. Foraminifers are most

abundant followed in numbers by mollusks and echinoids.

Age

On the base of fauna, Early Eocene age has been given to this unit(Kazmi and Abbasi, 2008)


51/93

FIG 3.10

Field Photograph of Sakesar Limestone showing Chert Nodules near Choa saidan shah City(Long 72

o59

/21

//E and Lat32

o43

/4

//N)


52/93


53/93


54/93

Chapter- 4

SEDIMENTARY STRUCTURES

Following sedimentary structures were observed from the Mapped Area.

4.1.Cross Bedding

4.2. Ripple Marks

4.3. Worm Tracks

4.4. Nodule Structure

4.5. Salt Pseudomorphs

4.6. Karen Structure


55/93

4.1. Cross Bedding:-

we observed Cross bedding in the mapped area these structures are present in Khewera

Snadstone in the Khewera Gorge.

FIG 4.1 : Field Photograph Showing Cross Bedding in Khewera Sandstone.


56/93

4.2. Ripple Marks:-

In the mapped area Oscilatory ripple marks were present at the base of KUssak Formation,

Baghanwala Formation and Warcha Sandstone .The ripples preset in the Kussak Formation is

Cross Ripple.

FIG 4.2 : Field Photograph Showing Ripple Marks in Kussak Formation.


57/93

4.3. Worm Tracks:-

We have observed worm Tracks and burrows in the Kussak Formation which were of the

vertical and horizontal type .the shally Portion of Jutana Formation was also Contain the

Burrows .

FIG 4.3 : Field Photograph Showing Worm tracks and Burrows in Kussak Formation.


58/93

4.4. Nodule Structures:

We observed large Nodules in the Namal Formation .These werw Chert Nodules .The nodules of

Namal Formation are longer than the Nodules of Sakesar Limestone.

FIG 4.3 : Field Photograph Showing Chert Nodules in Sakesar Limestone and Namal Formation


59/93

4.5. Salt Pseudomorphs:-

Salt Pseudomorphs were present in the Baghanwala Formation pf the mapped area .Great

exposure of Pseudomorphs was seen in the Baghanwala Formation near Pidh and Khewera

Gorge.

FIG 4.5 : Field Photograph Showing Salt Pseudomorphs in Baghanwala Formation near Pidh .


60/93

4.6. Karen Structures:-

Well Preserved Kurn Sedimentary Structure were found In the salt Range Formation in the

Khewera Gorge.

FIG 4.6 : Field Photograph Showing Kurn Structure in Salt Range Formatuion.


61/93

Chapter- 5

DEPOSI'I'IONAL ENVIRONMENTS

5.1. Salt Range Formation

The Saline deposits are formed by the precipitation of salts from concentrated solutions

or brines. Because the concentration is brought about by evaporation, the saline deposits have

been termed as evaporites. Rock salt (halite) gypsum and anhydrite are deposited in this way.

The Salt Range Formation consists of salt marl, clay, gypsum, anhydrite, dolomite and rock salt

(halite). The ultimate source of the Salt Range Formation is normal sea water. The deposition of

Salt Range Formation took place in an enclosed, shallow water and partially isolated basin

during Late Pre Cambrian . An arid climate prevailed resulting in the deposition of

evaporite deposits under oxidizing conditions. The elastics were derived from Indian Shield

(Peninsular India).

The Salt Range Formation was deposited in arid region, enclosed basin received large

quantities of dust from atmosphere and by streams during rainy seasons. The

terrigenous material settled to the bottom and gave rise to layers of clay which later on

changes into marl by the reaction of acid vapors and solutions (Oldham). Red color of marl

indicates arid oxidizing conditions at the time of deposition. Lack of stratification in the

Formation is due to the diaprism of salt. High salinity was responsible for the absence of life.

Provenance

Fineness of material and good sorting indicate prolonged transportation from the'Peninsular

India. Continuous subsidence of the basin and incoming of water resulted in huge accumulation

of evaporitic deposit.


62/93

5.2. Khewra Sandstone

The Formation predominantly consists of purple color, shaly, thinly bedded at base and thickly

to massively bedded at upper part. Presence of oscillatory ripple marks suggests shallow water

marine conditions.

After the deposition of Salt Range Formation, free supply of water began in the basin.

Numerous streams charged with the sediments from the Indian Shield drained into the basin.

The arid climatic conditions were prevailed at the time of deposition. The lower reddish,

purplish portion indicate high temperature and oxidizing conditions. The light colored upper

portion suggests less intensity of oxidation and relatively low temperature.

Lack of fossils and organic remains indicate high salinity and silica content suggests acidicmedium. (Pattijohn)

Origin and Provenance

Quartz grains are fine to medium, sub angular to sub rounded. Well sorting of quartz grains

show that the sandstone is texturally and mineralogically mature. Well sorting and maturity of

sandstone indicate a long transportation before deposition. It also suggests dilute depositing

medium with very mild subsidence of the basin during deposition.The source rocks were

possibly of granitic composition in the Southern India.

5.3. Kussak Formation

At the contact of Kussak Formation and K.hewra Sandstone a gritty conglomerate band is

present which shows a change in environment.

The Formation contains greenish grey glauconitic sandstone and greenish grey shale deposited

altematingly. The sandstone is micaceous. Alternation of shale and sandstone suggests cyclic

deposition i.e. during rainy season flooded streams were able to carry greater loads of coarser

sediments while during dry seasons load carrying capacity of streams reduced and only fine

materials were supplied and deposited.


63/93

Green color of the Formation is due to the presence of mineral glauconite. Glauconite is a

potassium iron silicate which is formed under conditions of slow sedimentation in a partially

restricted environment. Glauconite was derived from biotite by sub marine weathering

(GaJlihar1935). Glauconite is formed in marine environment at a moderate depth from 200

fathoms to 300 fathoms. According to Cloud (1955) glauconite is formed under marine waters

of normal salinity. It requires slightly reducing conditionsThe presence of oscillatory ripple

marks at the base also indicates shallow water marine conditions..Salinity of the sea water was

normal because fossils are present.

5.4. Jutana Formation

Jutana Formation in the Mapped Area is composed of massive light cream to white hard sandy

dolomite at basal part, Kussak like fossils bearing shales in the middle and pure massive

dolomite in upper part.

Lithology of Jutana Formation and presence of sedimentary structures like ripple marks indicate

a shallow water marine environment and arid climatic conditions. The basin was partiall y

isolated and became rich in Mg by continuous evaporation and inflow of water. By the

precipitation of CaC03, Mg rich sea water attacks the CaC03 and replaces it by forming

MgC03.

The dolomitization of CaC03 resulted in a decrease of volume by 12.30% hence the porosity of

rock increased. But the Jutana Formation is hard and compact so the replacement of CaC0 3 by

MgC03 took place before lithification.

Sandy basal part and shaly intercalations indicate a continuous supply of detritus during early

stages of deposition. During the deposition of pure dolomite, the supply of detritus was ceased

or reduced. The rate of deposition is thought to be very slow so continuous stirring of bottom

by wave action in shallow marine environment helped in replacement. Salinity was not too high

to flourish life as fossils are present.


64/93

5.5. Baghanwala Formation

The Formation consists of shale with intercalations of thin bedded flaggy sandstone. The flags

are pink, blue green or grey in color while shale is green and red in color.

Shales of the Formation are characterized by pseudomorphic casts of salt crystals which

indicate sufficiently high salinity in the water of depositional basin to form cubic crystals of rock

salt. Latter on these crystals were dissolved by the water and removed. The empty spaces of

the crystals were filled with silt or clay and were preserved. Green color of shale changing to

red is due to the oxidation of Fe+2 into Fe+3 Intercalations shale and sandstone is an evidence

of cyclic deposition which indicate that alternating wet and dry seasons were prevailed.

In short Baghanwala Formation was deposited in restricted basin of shallow depth whereoxidizing and arid climatic conditions were present. Salt pseudomorphs with absence of life

show the high salinity in the basin.

Provenance

Quartz and feldspar are the main constituent of the sandstone well sorting and fineness shows

a long transportation before deposition. The source of the sediments was same as Khev..Ta

Sandstone i.e. igneous rock but the sediments suffered a longer transportation due to the

shifting of shore line in retreating sea.

5.6. Tobra Formation

We noted glacial striations on faceted boulders of pink granite in the mapped area.. Striated

boulders suggest a glacial origin of the Formation.

Tobra mark an unconformity in the area. In the Mapped Area tilltic facies is present. It consists

of boulders and fragments of pink granite, quartz, phyllite and magnetite. The matrix is clayey

and sandy. Tobra Formation is very heterogeneous both in component material and in

assortment or stratification. Boulders of the Formation were transported from distant sources

by glaciers. These boulders are striated and faceted.


65/93

Provenance

The provenance was first local and then changed to distant. At the base of Tobra Formation,

boulders of Khewrite and Khewra Sandstone represent local contribution of material while the

boulders and fragments of igneous rocks indicate a source lied in south i.e. Rajputana. Nagar

Parker pink granite is an evidence of this.

5.7. Warcha Sandstone

Light red or purplish color sandstone intercalated with sandy shales of dark purple color

comprised the warchha sandstone in the Mapped Area This sandstone is heterogeneous coarse

grained and pebbly. Cross bedding and ripple marks are observed. Pebbles embedded in

sandstone are of pink granite and quartz.

Warchha Sandstone was deposited in shallow water, fluvial environment. After the deposition

of Tobra Formation subsidence of the basin took place. The subsidence of the Western and the

Central Salt Range was earlier and more rapid than Eastern Salt Range because Dandot

Formation is present there.

Purplish and red color of sandstone and shales indicate shallow water, oxidizing environment of

deposition. Darker color of shale than the sandstone is due to the even distribution of coloring

matter (iron oxide).

Poor sorting suggests rapid deposition by dilute depositing medium. Presence of pebbles in

sandstone show high velocity of water and high relief of provenance.

Origin and Provenance

Composition of Warchha Sandstone shows that the material was derived from igneous rocks.

Coarse unsorted and angular grains indicate a short transportation by rapidly flowing dilute

medium. Deposition took place in a wide depression of shallow water.


66/93

5.8.Namal Formation

Marly limestone of Namal Formation exhibits nodularity. It is richly fossiliferous and contains

both pelagic and benthonic fossil shells. The transitional contact between Patala and Namal

Formations indicate that transgressional sea changed swampy conditions into purelyshallow water marine environment.

Deposition of nodular limestone suggests high temperature and alkaline medium of

normal salinity in which life can flourish well that is why, the Formation is richly fossiliferous.

Marl was deposited as elastics by the streams flowing from land into the basin. Nodularity

may be developed by the process of sedimentation or may be formed due to shearing stress.

Provenance

Limestone is pure and fine grained. It is formed by direct extraction of CaC03 from sea water by

organic as well as inorganic means whereas marl is deposited mechanically by the incoming

streams.

5.9. Sakaser Limestone

Sakaser Limestone was deposited in shallow water marine environment. Hard compact and fine

limestone indicate relatively deeper water conditions than Narnmal Formation. Fairly constant

lithology and high lime content show calm and stable conditions of deposition. Like Namal

Formation, the limestone of Sakaser Formation also formed by direct extraction of CaC03 from

sea water by organic as well as inorganic means. Pelagic and benthonic fossils support shallow

water marine environment. Grey color is due to slightly reducing conditions. Absence of marl

indicates that stream action was ceased. Chert was formed by the post depositional

replacement of host rock by silica.


67/93

Chapter- 6

GEOLOGICAL STRUCTURES

6.1. Faults:

There are three local and small scale local faults

Reverse Fault Normal Fault Grungal Thrust Fault

6.1.1.Reverse Fault:

The fault is a reverse fault in which hanging wall moved upward. the fault is near to the Khewra

George.

6.1.2. Normal Fault

In the mapped area there is another normal fault near Khewra Gorge in which Hanging wall has

been moved down of relative to Foot Wall .

6.1.3. Grangul Thrust fault:

As we know that salt Range is thrusted over Punjab Plain on the large scale while there is also

local and small scale thrusted fault .This fault is near Choa Siden Shah City , and the Namal

Formation and sakesar Limestone has been thrusted and they formed a thrusted fault Which is

also known as Grangul Fault.

6.2. Unconformaties:

In the mapped area two major unconformities and one minor unconformity is present.


68/93

6.2.1. Disconformity:

A disconformity is found in the Early Cambrian Khewra sandstone and kussak Formation micro

conglomerate was present in the disconformity..

6.2.2. Permian unconformity

A well known unconformity is present between late Cambrian bgahanwala Formation and

Permian tobra Formation .tobra Formation mainly contains conglomerate which is a well

evidence of the unconformity.

6.2.3. Unconformity

There is another unconformity is present between a warcha sand stone and Namal Formation

in the mapped area.

6.2.4. Pidh Graben

Near the pidh area we observed a Grabon in the Nmal and Sakesar Limestone .The Graben two

sde were dipping equally about 40o .


69/93

Chapter- 7

7.1.Introduction

Geological explorations are basically concern with the hunting of new economic minerals and natural

resources present within the earth. Minerals and rocks have a role in the economic uplift of a country

and Pakistan is no exception in this regard. Their geological investigation, evaluation and reserve

estimation would be helpful for the user industry. In addition, the possibility of discovering petroleum in

commercial quantities from the Potwar Plateau cannot be ruled out.

The east central fraction of the Salt Range (Mapped Area) is important due to its diverse economic

potential. The area is prosperous in varieties of industrial raw materials, construction materials and

economic industrial minerals. The exposed stratigraphic sequence suggests important petroleum system

elements including potential source, seal and reservoir rocks for oil and gas generation and

accumulation.

7.2.Energy Resources

7.2.1.Petroleum Play

There are several individual petroleum systems in this area. Each element of petroleum play is described

separately. Table 7.1 shows the source, reservoir and seal rocks distribution in the stratigraphic column of

the Mapped Area along with the possible timing of hydrocarbon generation and Formation of traps.

Table Petroleum system and events chart for the east central Salt Range (Mapped Area).


70/93

Table 7.1 :Source Rocks ,Reservoir Rocks and Seal Rocks distribution in the Stratigraphy

Column of the Assigned area along with possible timing of hydrocarbon maturation and

Formation of the traps.

The stratigraphy of Salt Range has its subcrop extension under the Potwar Plateau. Therefore, the study

of outcrop units in Salt Range is very important and helpful to define the subsurface petroleum plays in

Potwar which is one of the onshore oil-prone areas in the world.

7.3. Source Rocks

There are several potential source rocks exposed in the mapped area. Among these are the well known

late Proterozoic Salt Range Formation.

The oldest potential source rocks are in the Salt Range Formation with a Total Organic Carbon (TOC) of

upto 36% (Bender and Raza, 1995) and oil yields of more than 20% (Kadri, 1995). The oil shales are


71/93

present in the upper part of the Formation and are associated with dolomite and gypsum. Silled and

reducing basin conditions were favourable for the preservation of organic matter at that time. The oil

shales of Salt Range are equivalent to the Precambrian oil source rocks of India, Oman and North Africa.

The oil shales were observed and sampled from Khewra Gorge Kadri (1995) described the presence of

coal in Cambrian rocks in these words:

Shales of Khewra, Kussak and Jutana Formations are of lacustrine to marine origin and contain woody,

coaly to variously amorphous kerogene which are capable of generating paraffinic to normal crude and

gas. The maturity level for these strata is very high for their present depth, indicating their original deep

burial and then removal of the overburden by up thrusting along the boundary faults of Salt Range.

There are indications that hydrocarbons were generated in Cambrian source rocks.

Baqri and Baloch (1991) also reported lenticular, deltaic coal beds in upper part of Khewra Sandstone at

Nilawahan Gorge.

The International Committee for Coal Petrology (1963) defines coal as, a combustible sedimentary rock

formed from plant remains in various stages of preservation---temperature and Pressure. Vascular land

plants only appeared during Middle Silurian (Stewart, 1983 and Taylor and Smoot, 1984). Therefore, the

presence of woody and coaly beds in Cambrian strata is not sound. Starting in the Precambrian till the

Devonian, the sole primary producer of organic matter was marine phytoplankton (algae and fungi) that

made black, organic matter rich, open marine shales (Tissot and Welte, 1984). Therefore, only algal-

matter derived organic matter may be present in the Cambrian rocks (Yasin, A.R., 1993).

Rocks of lower Permian sequence (Tobra, Dandot and Warchha Formations) are the possible source of

gas discovered in the Punjab Platform. Organic richness varies from 0.3 to 4.75%. The hydrogen index

ranges from 29 to 165 mgHC/gTOC. On the average it is fair to good. The organic petrography and

limited rock-eval data suggest that source is a mixture of Kerogene type II, type III and type IV (Ahmad et

al., 2007). Shales of Dandot Formation with some coaly partings are good source rocks (Kadri, 1995).

Paleocene presents and overall low energy and anoxic environment favoring the abundance and

preservation of organic matter. Upper Paleocene Patala Formation is considered to be the major source

rock of this region .TOC ranges from 0.5% to more than 3.5%, with an average of 1.4 percent, and are

type-II and -III kerogens (Wandrey et al., 2004). It has EOM/TOC ratio partly more than 150 and HI mostly

more than 200. The Formation was deposited in shallow marine to deltaic environment accounting for

the interpretation of both terrestrial and marine organic material. The latter gives rise to the generation

of normal crude oil while the former generates gas and paraffinic crude.


72/93

Maturation

The source rock maturity is mainly related to the geothermal gradients and the thickness of overburden.

The geothermal gradient of Potwar region ranges between 1.5C and 2.6C/100 m. Post Eocene

sediments have played a very important role in maturity of younger source rocks in depression areas.

This period accounts for rapid clastic sedimentation at the expense of Himalayan uplift and subsequent

erosion of uplifted rocks.

The organic matter preserved in the Salt Range Formation did not get the maturity until the Permian.

Because, the thickness of Cambrian rocks was not sufficient for the deep burial and maturation of

organic matter.

Maturity level of Permian rocks also appears to be very high since they have undergone tremendous

change on account of their burial through both time and temperature (Kadri, 1995).

The most important source rock reached the oil window during Pliocene (Bender and Raza, 1995). A

basin profile indicates vitrinite reflectance equivalent maturities of 0.62 to 1.0 percent for Tertiary rocks

in the productive part of the Potwar Basin (Wandrey et al., 2004).

Generation and Migration

Petroleum generation is directly related to the scale of time and the thermal regime, the strata is

subjected to.Rapid burial of Eocene and older rocks have placed them in petroleum generation window

in the basinal areas.

Generation of hydrocarbons most likely began in Late Cretaceous time for Infracambrian and Permian

source rocks and again from Pliocene time to the present for younger source rocks.

Even though there were probably two distinct periods of generation from two different groups of source

rocks, sufficient source-to-reservoir correlation data were not available to clearly define separate

petroleum systems. Migration is primarily over short distances updip and vertically into adjacent

reservoirs and through faults and fractures associated with plate collision and thrusting (Wandrey et al.,

2004).


73/93

7.4.Reservoir Rocks

Reservoir rocks include Khewra Sandstone, Jutana Formation, Baghanwala Formation, Tobra Formation

and Sakesar Limestone. More than 60 percent of the producing reservoirs (by field) are of Cenozoic age

in Potwar Plateau, with the majority of those being Eocene carbonates.

Fractured dolomite in the Salt Range Formation can form a suitable reservoir in the right setting with a

cap or seal to prevent migration. Possibility of entrapment of hydrocarbons in the overlying Formations

also exists, provided the hydrocarbons have not been destroyed during the hiatus of Ordovician to

Carboniferous times (Kadri, 1995).

Khewra Sandstone is the main potential Cambrian reservoir. The uniform grain size of sandstone and

sorting indicates its excellent reservoir character. The upper and middle units of the Formation are

moderately porous and display intergranular primary porosity which ranges from 10-15%. The

sandstone also shows fractures and jointing which may contribute to increase the effective

permeability. Oil is produced in Potwar area from Khewra Sandstone at Adhi, Chak Naurang and Rajian

Oil Fields.

Kussak Formation is generally tight. However, hydrocarbon shows are reported on both ditch sample

(fluorescence) and logs (Kadri, 1995).

The Jutana Formation is a good potential reservoir and hydrocarbon indications are reported in some

wells in the Potwar. It shows good porosity at outcrops, for example, honey-comb and fenestral

porosity). Upper part of the Formation has been proved as a good reservoir in the southeastern Potwar

area and oil is produced from Jutana Formation at Rajian Oil Fields.

Baghanwala Formation also has reservoir potential. Lower part of the Formation is a very well sorted,

medium grained quartz arenite which can act as an excellent reservoir .The visual porosity found by dye

injected thin sections is upto 15% .

The reservoir potential of the Permian rocks is also good. In the wells of the Potwar basin the Permian

sequence is very compact with very low porosity and permeability. At places Tobra Formation

depicts very good reservoir characteristics with presence of primary and

development of dissolution porosity (matrix porosities between 10% and 13%).

Moreover, sandstones of the Formation are fractured in vertical and horizontal

directions. However, Tobra Formation has flowed oil in Adhi Field (Kadri, 1995).


74/93

The Dandot Formation displays more shales than siltstones and sandstones. The siltstones and

sandstones are well sorted and possibly develop into local reservoirs. The Warchha Sandstone is

medium hard to friable, highly porous,

field report on khewra gorge and it,s surrounding areas

Documents