litho- and biostratigraphy of the lower eocene carbonate sequence in upper egypt: evidence for...

Jnurnol ~$?fA,jiicm~ Earth Sciences, Vol. 11; No. l/2: 151-168, 1990. 0899-5362/90 $3.00 + 0.00

Printed in Great Britain 0 1991 Pergamon Press plc

Litho- and biostratigraphy of the Lower Eocene carbonate sequence in Upper Egypt : evidence for uplifting and resedimentation

_ a- of tne Paieocene section

E. A. KEHEILA, H. A. SOLJMAN and ABD ALLA M. EL-AYYAT

Geology Dept.. Faculty of Science, Assiut University, Assiut, Egypt

Abstract - The Lower Eocene carbonate succession outcropping east of Qena and Sohag, Upper Egypt is divided into theThebes andDrunkaFormations. Field observations and petmgraphic analysis demonstrated intexilmgering relationship between these units. Moreover, the Assiuti Chalk and Manfalut Formations of Bishay (1961.1966) as well as the Thebes Formation of Said (1961) are considered here unique iithostratigrap-hit unit. Biostratigrap~hicaiiy. the Lower Eocene carbonates are subdivided into two larger foraminiferal zones : (l) Nummulites soliturius (discocyclina irregularislOpemdina libyca) Zone (Early Ypresian) and (2) Nummulites planulatustN. burdigalensis Zone (Late Yprehn) besides three algal zones of Late Ypresian age : (1) OvuZites maillolensis Zone followed upward by (2) Carpathoporella occidentaliszOne and (3)Belzungiu borneti he. These faunla and floral zones are correlated and all the identified larger foraminifera (nummulites, discocyclines and operculines) andcalcareous green algae (dasycladacean and codiacean) are point counted as well as their vertical distributions in six measured columnar sections are represented. Here, for the first time, coexistence of mixed Paleocene reworked planktonic foraminifers with the Ypresian sediments is recorded in the Thebes Formation. Therefore. we suggest that the Paleocene sequence in Egypt may have been subjected to uplifting and subaerial exposure followed by severe denudation during the Ypresian time.

INTRODUCTION

General statement In spite of the accessibility as well as numerous

works dealing with the Lower Eocene limestone plateau on both sides of the River Nile, many nlleetinnc rf=latinb t,e cnm P ctratidranhiral ~b.YYUV”” *Y’uL”‘~ Yv-*-” YU . ..L’~‘...y---w..*

problems remain without satisfactory answers. Examples of these problems are the contacts and the vertical and lateral relationships between the different rock units of bower Eocene, besides the boundary between the Early and bate Ypresian.

An area covering about 1140 square kilometers, and extendingbetweenQenaandSohag, on eastern side of the River Nile up to the western scarp of -__ ._ _ waai uena. was chosen and subjected to detaiied stratigraphical studies. This area is characterized by well exposed Lower Eocene stratigraphic sequence exhibiting vertical and lateral stratigraphical variations. It is believed that the study of this particular area may throw more light upon the litho- and biostratigraphic relationships between some of the bower Eocene carbonate units.

Previous work Not much detailed work has been done on the

area under investigation. The bower Eocene sequence in Egypt was dealt with through many

litho- and biostratigraphic studies carried out by Zittel (1883). Blanckenhom (1900 and 1921): BarronandHume(1902);Beadnell(1905); Cuvillier (1930); Nakkady (1958); Said (1960, 1962. 1971): B&hay (1961.1966): El-Naggar (1970): Amer etcd (1970):AbdEl-Razik(1972). Omara etcd., (1970, 1473\* Kenawv 114731 Calim flQ7RI Ahrl-Alla _V. -,, “wa’...“J \a.,. ‘,, *w-u*- \A.#. Y,, **.su *a...

(1974),KenawyandEl-Baradi(1977).Keheila(1978 and 1983). Moustafa ( 1979). Mahfouz ( 1980). Lot.@ (1980). Aref (1982) and Marzouk (1985).

Tables 1 and 2 summarize the different lithostratigraphic and biostratigraphic classifications previously proposed for the bower Eocene exposure of the Nile Valley.

Scope or’ tie present study In the present investigation, eight stratigraphic

columnar sections covering all the accessible parts of the studied area were described, measured and sampled in details (Figs. 5 and 6). The vertical and lateral relationships between the different recognized lithostratigraphic units characterizing the studied area were demonstrated through correlation diagrams (Figs. 2 and 3).

Detailed biostratigraphic zonation of the Lower Eocene sequence according to its content of larger foraminifera (nummulites, discocyclines and operculines) and calcareous green algae (dasycladacean and codiacean) has been carried

151

152 E. A. I&mm, H. A. SOLIMAN and Am ALLA M. EL-AYYAT

Table 2. Previous Lower Eocene biostratigraphic zonation in Upper Egypt. - _

AGE

/ ArmtoaS

andLauurY

Binhay (1961 md 1966), Niie Valley and Sinai

Kemvy (1972) Tmms~, Qrata

AM-Alla (1974) Nile Valley

Oman and Keiwy (1975) Khqa OGS

Kenawy and El-Band (1977) NE At&t

Mcustafa (1979) NE Sobag

Youssef (1982) NE Assiut

Aref (1982) Niie vlllcy

Keheila (1983) NE As&t

T EARLY EOCENE (YPRFSIAN)

1 - NwwwliraF &Serb Dkcmydina nudimwgo) Zone.

2-N. planulohLI

(Nummulitw otacicus) Zone.

-__

I Ntmmdites solitariau 7me.

3- Nummulites soliwiw Zone.

2- C011i0m.w nilmica zme. I- c0Pwc1ypeas deialiothica Zone

opemlbw-conolifem zute. l- Ntmmulites deserti zone.

I - Nummulites planulatrrs Zone.

B- Opcrcvlina libyca Subzone. A- Assilino grawlosa Suhzone.

-.- __----___

1 Nummditc.~ dir&u Zone.

2. N. pladatw Zone.

5- N. pkznvkuus Asdim placenbda Zone. 4- Ntmmulitcs atacicw zotle.

3- Alveolina d&pied pahcillata Zone.

1 - Nummniite.s atacicusl Nummulitu plmulabu Zone.

4- N. atacictu Zone.

3- Acetabularia (calc~pheres) sp. Zone. 2- Uva nileisis SUbZOtWZ.

B- Ovulites mordlpti Subzone. A- Carpathoporrlla occidmtolis Subzone.

3- Numulites atac&s Zone. 2- Giwamlla probkmoticd Alveolina Zone. I- Cirvamlla aegyptiacea Zone,

6- N. parts& Zone. S- Alvcolina fornasinii Zone.

4. Alveolino sp. Coralline olgoc Zone.

3. N. burdigaleusti zone. 2- N. p1aadaki.v Zone.

5- Ntmmtdites partschi zxu. 4- Alveolina oblonga 7me. 3. Orbitolites complanahu ih-ic. 2- Nvmmulitrs btvdigakmti Zone. I- N-US otacicvr Zone.

4- Iialimda praemonilir Zone. 3- Ovtdites dongok 7me. 2- Bolzmgia borncti zone. I - Ovulitar wdlolenrir zme.

Litho- and biostratigraphy of the Lower Eocene carbonate sequence in Upper Egypt

l 1. 2. 3. . . . . . . . . and 8, measured columnar sections. Fig. 1. Index map showing the location of the measured columnar sections and the different correlation trends,

in the studied area.

__---- ------

__-__-- - , -_

pJgZ-Of$-b-

.

Fig. 2. Lithostratigraphic correlation of the Thebes and the Diunka Formations along the North-south trend.

out. The recorded faunal and floral zones are correlated in Table 3. All the identified larger foraminifera and green algae were point counted and their vertical distributions in six columnar sections are represented in figures 8 to 10.

Furthermore, the reworked Paleocene microforaminifera (observed for the first time) and ostracodes which were recorded in the interbedded shales within the Thebes Formation, east of Nag’Hammadi (Section No. 51 and east of Girga (Section No. 6) were also identified and scanned with the aid of the Scanning Electron Microscope (SEMI.

__d_--_-----__----_--- - --------

- - -8 - - - - - ---

_-------_-_-- - - -t --_-------- -

6l Drunka 1

The&s Formation Formtim

Fig. 3. Litostratigraphic correlation of the Thebes and the Drunka Formations along the East-west trend.

The age of the different exposed rock units was discussed and the relationships between these units were demonstrated. The boundary between the Early and LateYpresian stages was postulated.

LITI-IOSTRATIGRAPHY

The Lower Eocene carbonates outcropping in the study area are divided into two rock units, namely, the Thebes Formation (Said, 196 1) and the Drunka Formation (El-Naggar. 1970).

Thebes Formation Distribution The Thebes Formation crops out mainly along the western scar-p of Wadi Qena, where it measures about 160 m in thickness and conformably overlies the Esna Shale.

According to our field observations and lithologic descriptions of the carbonate sequence in the study area, the middle and upper parts of the Thebes Formation exhibit inter-fingering contact with the Drunka Formation at the northwest of the area. This counterpart and time-equivalent relationship between the Thebes and the Dnmka Formations is demonstrated in Table 5 and Figs. 2 and 3.

Our study here indicates that the lithologic characters and faunal content of the Thebes Formation of Said ( 196 1) are completely similar to that of the Assiuti Chalk and Manfalut Formations of Bishay (1961, 1966). So all these units are considered here as a unique lithostratigraphic unit under the name Thebes Formation. Keheila recom- mends the division of the Eocene carbonate succession overlying the Esna Shale and underlying

E. A. KEHEKA, H. A. SOLJMAN and ABD ALU M. EL-AYYAT

Table 3. Correlation of the Lower Eocene floral and faunaI biostrati$raphic zones recorded in the area between Sohafl and Qena. Eastern Desert.

EARLY YPRESIAN LATE YPRESIAN

Nummulites solitarius Ovulites maillolensis

5 (Discocyclina irregularisl Operculina libyca) Zone

Nummulites plan&tuslNummdites burdigatensis Zone

NILE Nummulites solitarius Ovulites maillolensis Zone 6 (Discocyclina irregularisl

VALLEY Operculina libyca) Zone Numnulites planulatuslNummulites burdigalensis Zme

Carpathoporella occidentalis Belzungia Borner

7 Zone Zone

Nummulites planulatuslNummulites burdigalensis Zone

Nummulites solitarius 1 (Discocyclina irregularisl Nummulites planulatuslNummulites burdigalensis Zone

Operculina libyca) Zone WADI

2 Barren Numrnulites planulatuslNummulites burdigalensis Zone

QENA

3 Barren Nummulites planulatuslNumnulites burdigalensis Zone

4 Barren Nummulites planulatuslNummulites burdigalensis Zone

!i

J I

J

lying the Qarara Formation into : the Thebes, Drunka and Minia Formations below and the Samalut and Maghagha Formations above.

Lithaogy The Thebes Formation in the study area is divided vertically into. lower, middle and upper lithofacies. These are not unique mappable stratigraphic units, but rather sequences of strata that represent similar depositional conditions.

parts of the area. Petrographic analysis of these carbonates show the presence of sparse bioclasts of pelecypods, echinoderms, gastropods as well as higher percentages of reworked planktonic foraminiferal chambers. These allochemical components especially, the reworked microforaminifera are distributed in alternated bands and scattered lenses.

The lower lithofacies of the Thebes Formation is well represented along the western scar-p of Wadi Qena (measures 25 m inthickness). It ischaracter- ized by light grey, hard, massive and sometimes fissile. rhythmic sequence of calcareous shales and marls grading upwards into chalky and dolomitic fine gratned limestones. Scattered chert nodules are recorded throughout this lithofacies, which tend to be most common in its upper portion.

Alongthe NileValley (in Sections No. 5 and 61, the middle part of the Thebes Formation is intercalated by two remarkable greyish to yellowish green calcareous shale horizons b-each 1.5 m in thickness). These recorded shales are rich in articulated and disarticulated ostracodes of Ypresian age which were mixed with reworked, ill preserved and fragmented planktonic foraminifera of Paleocene age.

The middle lithofacies is mainly yellowish white, thinly laminated, rhythmic pure and dolomitic lime mudstones and wackestones rich in chert nodules and bands.

X-ray diffraction and careful microscopic examination of the Thebes carbonates demonstrate the extensive occurrence of dolomitized limestones sharing the composition of the sequence. Evaporite minerals such as gypsum, anhydrite and halite show a parallel occurrence with dolomites.

This lithofacies forms almost the Thebes The upper lithofacies of the Thebes Formation Formation succession in the eastern and southern (reaches 56 m in thickness) is marked by hard,

Litho- and biostratigraphy of the Lower Eocene carbonate sequence in Upper Egypt 155

Table 4. Distribution of the larger foraminifera in the Lower Eocene sequence exposed be%ween Sohag and C&ma. Eastern Desert.

/

I NS Zone

Age

Rock unit

Biozone

Nummulites solitarius de la Harpe A-form N. frassi de la Harpe A-form N. pratti d’archiac and Haime A-form Discocyclina irregularis Doncieux Operculina libyca Schwager Operculina jiwani Davies Nummulites planulatus Lamarck B-form N. burdigalensis de la Harpe N. atacicus L.eymerie B-form N. globulus Lqmerie N. partschi de la Harpe A-form Assilina sp.

NS = Nummulites solitarius (Discocyclina irregularislOperculina libyca) Zone Np = N. planulatusiNummulites burdigalemis Zone.

Table 5. Counterpart and time-equivalent relationship between Thebes and Drunka Formation

Rock units I Age I

Drunka

Formation

Thebes

Formation

Late

Ypresian

dark grey, silicified nummulitic limestone sheets intercalated with burrowed and mud supported limestones. Discocyclines, operculines and oysters are also recorded in this lithofacies. Moreover, intraformational conglomerates, composed mainly of intraclasts and lime mudstone litho- calasts form lenses repeated vertically in several horizons.

Several minor and major erosive discontinuity surfaces (diastems) are recordedwithintheThebes Formation. The most pronounced diastems are located in the middle part of the unit and are characterized by coarse grained phosphatic limestones (up to 5 cm in thickness).

Sedimentologically. the Thebes Formation in the study area is believed to be deposited in tidal flat environment with semi-restricted water circulation, and tempestite nummulites bank environment (Keheila and El-Ayyat, 1989).

Druuka Formation Distribution In the present study, the Drunka

Formation (up to 186 m in thickness) is well represented and traced mainly in the northwest- em parts, and along the eastern bank of the Nile Valley between Nag’I-Iammadi and Sohag (Figs. 2 and 3). The main body of the Dnmka Formation is located outside the study area towards the northwest (Moustafa, 1979; Mahfouz. 1980; L&y. 1980; Keheila. 1983 ).

Lithology The Drunka Formation is composed of snow white, hard. medium to thick bedded and massive limestones which exhibit planar and trough cross beddings in the upper most part. Oolites and skeletal fragments are the main constituents of the cross bedded limestones. Very dense bioturbated horizons of burrows and boring sometimes are repeating vertically forming intraformational conglomerate horizons.

The fauna1 content of this rock unit includes high percentages of calcareous green algae (codiaceans and dasycladaceans) , bryozoa, nummulites, pelecypods. gastropods, and echinoderm bioclasts.

156 E. A. KEHEU, H. A. SOLJMAN aad ABD ALLA M. EL-AYYAT

NummuliteS

DiscOCyClines

Operculines

Pelecypods

Gssteopods

Skeletal debris

Cellophane grains

Oolites

Flint nodules

Silicified bands

Silicified concret- ions

papery lime-mudstone 1- Nummulites so&tarius (Discoc~..~c&tain-egula&/ nodular lime-mudstone Opercr.&nu Libycc3 Zone, Fig. 12: Intraformationalcarglonerate

Calcareous shale

DefWtfon This zone occupies the interval from the first appearance of Nununulifes soIiturius de la Harpe to the first recording of the NununuZf.tes planulatus Lamarck B-form and Nummulites burdigalensis de la Harpe. Assocfatfon Nwnmulites solitwius A-form, N.

fiassi de la Harpe A-form, N. pratti d’archiac and Haime A-form, N, globulus Leymerie, DlscocycZfna irregularies Doncieux, opercultna Libyca Schwager, Operculinajiwuni Davies and Assilina sp.

Occurrence This zone defines the lower part of the Lower Eocene succession (Thebes Formation) along the Nile Valley (Sections No. 5 and 6). It shows lateral decrease in thickness towards both south and east directions.

r r Cross bedding 77 El "I

sg* Bioturbation

Grainstone

Packstone

Lime-mudstone

Fig. 4. Legend for the carbonate constituents of the measured columar sections.

Sedirnentologically, the Drunka Formation constructs an open shelf lagoon of restrlcted circulation, with well washed and winnowed bar facies at its uppermost part (Keheila and El-Ayyat. 1989).

BlOSTRATIGRAPHIC ZONATION

For detailed biostratigraphic zonation of the Lower Eocene sequence in the area east of Qena and Sohag, the eight stratigraphic columnar sections were paleontologically analyzed. All the recorded calcareous green algae, smaller and larger foraminifera were identified. Careful point counting of these taxons was carried out and their vertical distribution is represented in Figs. 8 to 10. Accordingly, the well defined lithologic units in the study area were divided into three algal biozones and two larger foraminiferal biozones as follows:

The algal &ones:

3- Belzungiu bometi Zone 2- Carpathopor&aoccid.ent&s Zone

Early Eocene&ate Ypresian) Base l- Ovulites mailloIensis Zone

The larger forasnidferal zones: 2- Nummulites planulatus/Nummufftes

burdigalensls Zone Late Ypresian

Base 1 - Nummtiites solUarks (Discacyclina irreguZwfs/Opercuftna li.byca) Zone Early Ypresian

These floral and fauna1 zones are correlated as shown in Table 3 and the vertical distribution of the index fossils within these biozones is sum- marized in Table 4.

Remarks This mne was first introduced and described by Schaub ( 195 1) from the Lower Ypresian sequence of the Schlierenflysch in Switzerland, Kenawy (1972) and Aref ( 1982) recorded this zone in the Lower Ypresian rocks of Upper Egypt. This assemblage zone is equivalent to the Nummulites deserti/NununulitesfmssiZone which was recorded by Cuvillier (1930) from the Lower Libyan Series (Lower Eocene). Said and Kerdany (196 1) found it in the Esna Shale and Lower Farafra limestone. Fahmy et al. (1969) recognized Nummulftes desertt. in the Lower Eocene reefal facies in the Gulf of Suez.

Age Early Ypresian.

2-Nununulites planulatus /Nw-runulites burdiga- Zensfs Zone, Fig. 12

De&Won It is characterized by the total range of the zonal guide fossils. Asmciation Nummulites planulatus Lamarck,

Nununulites burdigalensis de la Harpe. N. pqrtischi de la Harpe A-form, N. atucf.cus Leymerie B-form, N. globulus Leymerie and Assilina sp.

Occurrence This zone is found through the upper part of the Thebes Formation (maximum thickness was recorded in Section No. 1). Along the Nile Valley this zone is recorded in Sections No. 6 and 5.

Remarks This zone was first introduced by Hottinger and Schaub (1960). Nummulites pZam&tusLamarck and Nummulites burdigc&nsis de la Harpe were considered as important index fossils in the Late Ypresian of the world by Douville (1919) from France, Schaub (1951) from Swiss Alps,HottingerandSchaub(1960).Kenawy(1972). Kenawy and El-Baradi ( 1977) and Aref ( 1982) from Egypt. This zone is considered as time equivalent to Ovulftes matllolensis, Carpathoporella occidentalis, and Bekungtu bometi zones.

Age Late Ypresian.


NO. 2 NO. 3

m 9.6

0 I

In 6.6

NO. 4 1

NO. 1 I I

(Legend in fig & )

Fig. 5. Stratigraphic columnar Sections No. 2. 3, 4 and 7.

Green Algal Zonation Calcareous green algae were identified and

classified into three major floral zones. These biozones are confined mainly to the Drunka Formation and none of the floral taxons were observed in the carbonate succession of the Thebes Formation. The geometry of the algal zones is wedge-like. The rnardmum recorded thickness of these bimones is represented at the north and northwestern parts of the study area, along the

Nile Valley. General thinning and finally missing of the algal zones were reported towards the eastern, southeastern and southern directions. Along Wadi Qena, all the stratigraphic measured Sections No. 1.2.3 and 4 are barren of the calcareous algae (Figs. 8 and 9).

The following are description and discussion of the recorded green algal biozones.

(1) Ouulites maiU.oZensis Zone Definition This biozone is identified in the study

E. A. KEWJLA, H. A. SOLJMAN and ABD ALLA M. EL-AYYAT 158

NO 1

ILegend in fig C 1

NO S

Fig. 6. Stratigraphic columnar Sections No. 1, 5, 6 and 8.

area by the total range of the tonal marker. It is conformably underlying the Ccupathoporellu occidetalis Zone.

Aseociation The fauna1 assemblage of this zone is composed mainly of Ouulites matZZoZensfs Morellet (up to 30 O/6 of the rock, Fig. 111,

m

9.6

0 1

NU 8 --

m 3.6

Curpathoporella occidetalis Dragastan (8 %I OccurrenceThe OuulitesmailZokn.sisZone main- I&&me& p~aenuWU.s Morellet (6 o/o). ly coincides with the lower exposed part of the


sl I-r OwLCite. cLongab cl Y Didcocycfina ia*egulcniA c-

-::: q :-I.: CcmpathopoaeLLa occidentaLid

N-&A (A-f-1

cl Zooa Hatimeda p*aemoniCiA 000

Nwaut.&~ (B-form)

ovtiu mailc0len.Ai.A Opad_ina Libyco 6 Op.jiwani.

Fig. 7. Legend for the types of calcareous green algae and larger f0ramMfex-s recorded in the measured stratigraphk

columnar sections.

Drunka Formatfon at the eastern bank of the Nile Valley between Qena and Sohag. The thickness of this floral zone varies widely from place to place andshowsthinningsouthandeastwards.AtSection No. 5 the Ouulites maillofensfs Zone is represented vertically by a thickness measuring 69.5 m. Near Girga (Section No. 6). this zone exhibits a wide vertical distribution measuring about 122.6 m.

Remarks The Out&es maillolensfs Zone is introduced by Keheila (1983). This zone is correlatable with the Uua n&n&s Zone, identified by Moustafa ( 1979) at the northeast of Sohag and is also equivalent to the Giruanella aegypfIa.ca Zone and GfrvanelZtxprobZenuztica/AZveoliruzZone. recorded by Youssef et al. (1982) at the northwest of Assiut.

The index fossil calcareous green algae Ouulites mafllolen.sisMorellet was described in the Ypresian sequence of Corbieres Septentrionals by Massieux (1966 and 1969). Carpathoporella occidetalfs Dragastan was recorded by Johnson ( 1969) from North America Lower Eocene sequence and by Moustafa (1979). and Keheila ( 1983) from the Ypresian sequence of Egypt.

Age The OuuZftes m&U&nsis Zone is dated here an Early Eocene (Late Ypresian) age.

(2) Cur-pathoporella occidfzntaUs Zone Definition This zone is defined by the enrich-

ment of Carpathoporella occtdentaUs Dragastan (Fig. 11) which represents about 22 % of the rock. The upper boundary of the zone is delineated at the first appearance of the Belzungia bometiMorellet, and the lower boundary is approximately marked by the disappearance of the Ovulites m&.ZZo6enszS Morellet.

Association The fossil content of this zone is essentially composed of Carpathoporella occtdentaUs Dragastan (up to 22 % of the rock), Halimeda p memontlis Morellet (up to 10 O/o) and

Out&es elongata Lamarck (up to 6 O/6. Fig. 11). Occurrence This zone is developed mainly in the

exposed part of the Drunka Formation along the Nile Valley. The sequence of this biozone reflects a general thinning towards the south. Near Nag ‘Hammadi at the south, it vertically extends about 7.75 m in thickness in the top of Section No. 5. At the northwestern parts of the study area and east of Sohag, it becomes wider and shows larger vertical extension (61.8 m in thickness).

Remarks The same zone was identified by Johnson ( 1969) from the Lower Eocene sequence in North America. Moreover, Moustafa (1979). Mahfouz ( 19801 and Keheila (1983) described this zone in the Lower Eocene of the Nile Valley, Egypt.

(3) Bekwgia bometi Zone Definition This zone is identified by the first

appearance of Belzungia bometi Morellet which represents about 2-5 O/6 of the rock. The upper boundary of thiszone is not recorded in the studied sequence.

Association The fossil assemblage of this zone is essentially composed of Bekungia bometi Morellet (Fig. 11). Curpathoporella occtdetnalis Dragastan (3 %) HaZtmeda praernonilts Morellet (3 %I.

Occurrence This zone is recorded in the topmost part of the Drunka Formation, east of Sohag (Section No. 7). The maximum recorded thickness of this zone is about 46.35 m (west of Sohag, in Section No. 8). Southwards, near Girga (Section No. 6). and near Nag’Hammadi (Section No. 5). this zone is completely missing.

Remarks The zone is not well represented in the study area. However, the presence of the zone only at the east and west of Sohag and its completely missing at the southern parts of the study area, suggests that the main original body of this zone may be located outside the study area probably towards the north and northwest. Kehefla ( 1983) recorded this zone for the first time in the Lower Eocene sequence northeast of Assiut and he considered it as the time equivalent to the Orbit&es complanatus Zone (Late Ypresian), The Belzungta bomeff Morellet was recorded by Morellet (1908, 19 13 and 19 17~) in the Upper Thanetian of the Paris Basin. Morellet (1917d and 1940b) and Massieux (1966b) identified the same zone in the Eocene of Bretagne and Contentin. This zone was also described in the Paleocene, Lower and Middle Eocene sequences by Elliott ( 1955.1968) as well as in the Eocene of Somalie. Egypt and Corbieres Septentrionals by Massieux (1966b. 1973).

Age The age of the Belzungta bometi Zone is considered here an Early Eocene (Late Ypresian) .

160 E. A. KEHEILA, H. A. SOL&IAN and ABD ALLA M. EL-AYYAT

t Larger foremini. 8 Reworked plarktonice zonee.

Fig. 8. Biomnes and vertical distribution of calcareous green algae, larger foraminffers and reworked planktonic foraminifers in Section No. 1 and 6.

&-5gend In Fig. 7J. IO.3

Y ?

Y

:

I

~Nutmutiles p&nut- ? h..&.bukdi&- 2 en&b Zone.

0 Nunmdited so-fit-

-

Q -

8 Apostolescu, Fig. 14). These calcareous shales overlie the lVummuliies sditmius (Discocyclina

Careful examination of the microforamitieral irregularis/Operculina libyca) Zone (Early contentoftwoshalebeds,intercalatingtheThebes Ypresian) in Sections No. 5 and 6. Formation, reveals the coexistence of Paleocene The recorded Paleocene reworked planktonics reworked foraminifera (Fig. 14) with the Ypreslan are: Planorotaiites pseudomenardli Bolli, ostracodes (Legwnfnocythereis a. lokossaensfs Gbborotaba compressa Plummer. Planorotalites


IO 20%

No. 3 I!!!! lo 20 30 4on

No. 2

Fig. 9. Biozones and vertical distribution of calcareous green algae, larger foraminifera and reworked planktonic foraminifera in Sections No. 2 and 3. (Legend in Fig. 7).

pusillapu.sUZa (Bolli), Morozouella uncm (Bolli), MorozoueZZa angulata (White) and GZobfgerirxx 6Uoc~&~H&s Pl er.

The foraminifera un!n tests show relatively bad preservation due to worn and external abrasion. Moreover, they are fragmented with isolated chambers. The condensation of the plankton&s in tightly packed layers and lenses and their complete absence in others, probably was depend- ing on the rate of influx (by streams and channels) of these reworked material from outcrops outside the depositional basin. DHerent authors (Said. 1960.1961 and 1962: El-Naggar, 1968 and 1970: Said and Sabry. 1964; and Marzouk. 1985) recorded the absence of Paleocene biozones from the Upper Cretaceous-Lower Tertiary south and

southeast of the study area. It is believed that the potential source area of the

reworked Paleocene microforaminifera was located in the east of Qena and in some parts along the Red Sea coast. The Paleocene sequence may have been subjected to uplifting and subaerial exposure followed by severe denudation during the Ypresian time. As the result of this catastrophic event, the paleontologic absence of some Paleocene assemblages took place.

We therefore suggest that the absence of parts of the Paleocene in some areas of Upper Egypt was probably controlled by uplifting and subaerial erosion of the Paleocene sequence rather than the absence of sedimentation during that time.

162 E. A. KWEILA, H. A. SOLIMAN and ABD AJLA M. EL-AYYAT

. . h

:..L’.:.;.:., 0 F ‘:**.*. ..*: . . . . a.., .

..,*.a _ . . . ..* :.*.* *..

5 t” f L-

10 20 30%

No.7

Fig. 10. Biozones and vertical distribution of calcareous green algae, larger foraminifera and reworked planktonic foraminifera in Sections No. 5 and 7. tLegend in Fig. 7).


FY.sJ 11. (A. M. g Hallmeda pmemmth Morellet. Lon@tudiml sectiona. A=X22,M=XlS,T=X20. Drunka FormaUon. Secthns No. 7 and 8.

(8. C. HI BeLungfa bixnetlMonllet IQ. R s) (EI and Ct Oblique transvcrac sectlom. (III I.on@hadinal sec~on B = X 45. C = X 40. H = X 22, Dnmka Formation. Section No. 7.

CD. E. F. G. 1. J. Ka r, N. p. VI ccupot+Un madetolls Dragastm 0. U) ID. E. F. G) l.on@h~dlnal aectlona. (0 Oblfque longltudiml section.

(K) Oblrque transwsal section. CJ. I. w lhmversal sections. D = X 45, E= X40.F=X30.G=X30.1=X45.J=X60.K=X40.L=X55.N= X 45. P = X 20. V = X 18. Drunka Formation. Section No. 5. Nummuhs bwd@ensfs Morellet. Transvemal sections. Q-X 25, R = X 27. S = X 30. Note the geoptal fabric in fi.@n [Ql h-unka FomatIon, Section No. 5. 0vuIft.s ebrgata Iamarck. group ofoblfque lon(9tudinal and tranavaual sectkms. -ted with Ch-pathD~ua cxck-htalis Dragwan. 0-x 35 U=X 20. Drunka Formation, Sectlcm No. 5.

E. A. KEHEILA. H. A. SOLIMAN and ABD ALLA M. EL.-AYYAT

12. WNummuhs burd4galensfs de la Harpe (axial and equatofial sectlons. A and B-f-l. Ihla aamnbkue remarks the N. dmuLzh~s/N.

IE) Opexxkna~nl Davies wmmunlty which remarks the Lower Ypm sequmcc along the Nile Valley (c~hmnar SectIon No. 5). X = 5. NC@

Pdt (F and H) Ntumu&ta sduorlus de la Harpe A-form community showing the

domlnanceoftblaspedesintheN.sdUartm~lrrsguti Opmxdtm libycx$ Zom. at the Nde ValIey @ection No.5. Early Ypreet Photo (Hj amtalus Nxmmuk&~r de la Hprpc A-form (equatmial section tn upper xi&j and Asstkna sp. Power middle of tbc photo) P lO.H=XlO.Ne@tv+prfnt

ICI Nummukim atadcuJ Leyme~Ie (A and B-forms) of the Late Ypreeian at NfleV&y#ectlonNo. 5)~WadlQena(Sect(onNo.3l.G =X lO.Ne@

PtiL

tlv.2

4 an).

=x

the


- bu@&nstr de la Harp A and B-forms (axial and equatorial scctlons). A= X 12. B = X 15. ~~obulusLeymale(~al~ons.B-fofin).B=X3.D=X4.FandG=X3. - pmtfi d’A&iac and Hatme A-fmm km&l secttonI. X 3. N- &&s&t de In Harp A-f mm (C and 19 and B-form (E and Q). axial secti ons.C=X6.K=XlO.EandQ=X5.

DLso?lcltna~~eux(ardllmdobllqueaxial8ectiom). L=X7.O=X15,P=X12. opS-_WQnl lhle~ h-l and obltque mdal sections). R - X 6. S = X 6. T = X 10. 0p-b =wPger -munity ku-ial and oblique adal sections) with Dfsacych heguhzr& (in the lower I& comer) X 6. N- adanub Lamerck. axial aectio~. I = X 40. J = X 45. Nummukes ai- Leymexle B-form ad111 sectton. X 60.

166 E. A. KEHEILA, H. A. SOLJMAN and ABD ALLA M. EL-AYYAT

Litho- and biostratigraphy of the Lowa

EABLYYFRBSIAWLATE YPRBSIANBOUNDAtkY

The contact between the Early and Late Ypresian in the studied succession is determined at the boundary between the NumrnuMes soli&ufus OXscocycm ~egufaris/OpexuZina Iibycal Zone. and the N. pZanulatus/N. burdf,gd.emis Zone. Along the Nile Valley the Late Ypresian is marked by the presence of the OLXLWS r?taiZloZensfs, Caqx&~porelZaocci&talls andBelzu.ngiabometi zones. The contact between the Early and Late Ypresian is assigned for the lower part of the Thebes Formation. This is in accordance with the results of Kenawy (1972). Abd-Alla (1974). Faris (1974) and Aref (1976 and 1982) in Upper Egypt.

Thebes Formation The exposed Thebes Formation In the studied area includes the following larger foraminiferal zones: Base: l- N ummuzites sozitcuius (Discocyc~ina

frregul.wis/OpecuZina libyca) Zone. 2- Numm&tesplanuftztus/Nwrun~&tes

burdfgahsis Zone.

Thebes biozones suggest Early Eocene (Early to Late Ypresian) age for the Thebes Formation.

Drunka Formation This rock unit is occupied by three floral zones.

from base upwards are: Ouulftes maiZl&nsisZone. Carpc&hoporeUa occidentalis Zone and Behngia bornett2Ione. These biozones suggest that the age of the Drunka Formation is Early Eocene (Late Ypresian).

Abd-Alla, A. A. 1974. Geological and paleontological studies on the Lower Eocene of the Nile Valley, Egypt. M.&J. Thesis, Assiut University.

Abd El-Razlk T. M. 1972. Comparatlve studies on the Upper Cretaceous-Early Paleogene sediments on the Red Sea coast, Nile Valley and Western Desert, Egypt (U&R.). Sixth Arab petrol. Congr..Algiere, Paper71(B- 3). l-23.

Amer. A. F.. Krintsov. M. I. and Hanna. F. L. 1970. The Egyptlan Carbonate rocks and the possibilities of their utillsation. In: 0. Moharran etal (Eds) Studies on some mineral deposits of Egypt. Geological Survey of Egypt. 195-208.

Aref, M. A. 1976. Microplaeontological and biostratigra- phical studies on some Late Cretaceous- Early Tertisuy sections in the Eastern Desert, NileValley and Western Desert. M.Sc. Thesis, Assiut University, Egypt.

r Eocene carbonate sequence in Upper Egypt 167

Aref, M. k 1982. Micropaleontology and biostratigraphy of the Eocene rocks in the area between Assiut and Benl Suef east of the Nile Valley-Egypt. Ph.D. Thesis, Assiut Unlversily.

Barron. T. and Hume. W. 1902. Topography and geology of the Eastern Desert of Egypt (central portion). Egypt Survey Department, Cairo, 331 p.

Beadnell, H. J. L. 1905. The relation of the Eocene and Cretaceous Systems in the Esna-Aswan Reach of the NileValley. Quart. J. Geol. Sot. London Il. 269-278.

Bishay, Y. 196 1. Biostratigmphic study of the Eocene in theEastemDesertbetweenSamalutandAssiutbythe Larger Foraminlfera. Third Arab Petrol. Congr.. Alexan&& 2. p. 13.

Bishay. Y. 1966. Studies on the larger foramlnlferaof the Eocene (the Nile Valley between Assiut and Cairo and SW. Sinai). Ph.D. Thesis, Alexandria University.

Blanckenhom. M. 1900. Neues Zun Geologle und Paleontologle Aegyptens. Das Paleogen (Eocene and Oligocaen) 2 Den. Geol. Ges. 52.

Blanckenhom, M. 192 1. Handbuch der regionalen geologle. Bd.. VIII. Abt. 9. Heft 23. Aegypten Carl Winteres Universitat sbuchandlung Heidlberg, 244 p.

Cuvilller, J. 1930. Revision du Nummulitique Egyptlen. M&m. Inst. d’Egypt. l&37 p.

Douvllle, H. 1919. L’Eo&ne tirleur en Aqultaine et dans les Pyr&&s. Mem. Carte g&l. France, 79 p. Paris.

Elliott. G. F. 1955. Fossil calcareous algae from the Middle East. Macropal.. l(2). 123-131.

Elliott. G. F. 1968. Permian to Paleocene cakareous algae (Dasycladace~ of the Middle East. Bull BrU. Mus. Nat. H&t. (Ged) supplt. 4, l- 111.16 Fig.. 24 Pls.

El-Naggar, 2. R., 1968. Stratlgraphy and classification of type Esna Group of Egypt (Reply). Am. Assoc. Petrd Geol. Bull.. 62. 1794- 1798.

El-Naggar. 2. R. 1970. On a proposed Lithostratigraphic sub-division for the Late Cretaceous-Lower Early Paleogene succession in the NileValley, Egypt. (U.A.R.) 7th. Arab Petrol. Congr. Kuu~ait64(&3)), l-50.

Fahmy, S., Krasheninnikov, V.. Mlkhalov, J. and Samodurov, V. 1969. Biostratlgraphy of Paleocene deposits in Egypt. Proc. IIIrd AMcan M&m. Cokq. 33, 477-484, Table 1.

Faris. M. 1974. Geological and paleontologlcal studies on the Late Cretaceous- Early Tertiary succession in Qena region and Kharga Oasis. M.Sc. Thesis, Assiut University.

Hottinger. L. and Schaub, H. 1960. ZurStufenelntellung des Paleocaens und des Eocaens. Einffihrung der Stufen IIer dien und Biarritzlen. Eclogae Ceol. Helu., 63(l), 453-479.

Bagel. Johnson, J. H. 1969. A review of the Lower Cretaceous algae. ColoradoSchoolMfnesPro~ &Mb.. 6. 180 p.

Keheila. E. A. 1978. Geological studies on the area Southeast of Minla. M.Sc. Thesis, Assiut University.

Keheila. E. k 1983. Sedlmentology and stratlgraphy of the carbonate rocks in the area northeast of Assiut. Ph.D. Thesis. Assiut University.

Keheila, E. A. and El-Ayyat, A. M. 1989. Lower Eocene carbonate fades, environments and sedimentary cycles, evidence for global sea-level changes. The Geological Society of Egypt (Abstract)

168 E. A. KEHEILA, H. A. Sow and ABD ALLA M. EL-AYYAT

Kenawy, A. I. 1972. Larger foraminifera from the Lower Eocene Thebes Formation, Taramsa section, Qena. Egypt. Magyar AlIami Foldtani Intezet Evi. Jelentese.

Kenawy, A I. and El-Baradi. N. M. 1977. Early and Middle Eocene foramfnifera in the environs of Assiut, Egypt. Bull, Fat. Set Assfdt Univ. 6(l), 247- 293.

Lotiy. 2. H. 1980. Geological studies on the area to the north-west of Assiut. MSc. Thesis, Assiut University.

Mahfouz. S. 1986. Geological studies on the area west and south-west ofSohag. MSc. Thesis, Department of Geology, Assiut university.

Mansour, H. H. and Phflobbos. E. R 1983. Idtho- stratigraphic classiilcation of the surface Eocene carbonates of the Nile Valley. Egypt: A Review. BUZZ. Fat. Sci. Assiut University, e(2), 293-366.

Marzouk, A. M. 1985. Sedimentological and stratigraphicaI studies on the Upper Cretaceous- Lower Tertiary succession near Qena-Egypt. M.Sc. Thesis, Tanta University.

Massieux, M. lQ66b. Les algues du Nummulitique egyptien et des terrains c&tads-&oc&ies de quelques regions m&og&nnes. 2&me partie. Etude critique. Rev. Mfcropd, S(3). 135-146.2 Figs.

Massieux. M. 1969. Contribution P l’itude stratigra-phique et micropaI&ontologique de lEoc&ne des corbiires septentrionales (Aude). These de Doctorat d’Etat en Sciences Naturelles, Faculte de Science de Paris.

Massieux, M. 1973. Micropaleontologie at stratigra-phique de IEocene des corbieres septentrionales (Aude). Cah. Pal., C.N.RS. Ed., 146 p., 17 Figs. 1 dp l., 29 Pls.

MoreIIet, L. 1908. DeuxaIgues siphon&es vertidl&es du Thanetien de Boncourt (Oise). Bull. Sot., g&d. I?.. 4&rne ser., t. VIII, 96-99,2 Figs.

MoreIIet, L. 19 13. I_es DasycIadacees du Tertiaire park&m. Mem.Soc.G&oLFr.,PoI,t.21,fasc.1,Mem,47,p.43. 24 Figs, 1 Table, 3 Pls.

Morellet, L. 1917~. Contribution a l’etude de la flore phycologique du Thaneiien. C.R sonun SCIC. g&d. I’+., 16, p. 213-214.

Morellet. L. 1917d. Note preIiminaire sur les Dasycladacees de I’Eoc&e de la Bretagne et du Contentin. C.R somm. Sot. geol. Fr., p. 84.

Morellet. L. lQ4Ob. Etudes sur les algues calcaires de lEoc&ne du Contentin. Bull. Sot. g&d. Fk., 5&me Ser., t. x, 201-266.2 Figs.

Moustaia. H. A 1979. Geological studies on the area northeast of Sohag. M.Sc. Thesis. Assiut University.

Nakkady, S. E. 1958. Stratigraphic and Petroleum Geology of Egypt. University of Assiut, Mon~raph Series 1.

Omara. S.. El-TahIawi, R and Hafez, H. 1970. ‘Ihe Geology of the environs of As&tit. B&I. Sot. GeograPh Egypt, 43, Cairo.

Omara, S., El-Tahlawi, R 1972. Limestone “dykes” in theNiIeVaIIeyaroundAssiut.UpperEgypt. N.Jb.GeoI. PuIeont. iUh.. H. 8.475-483.

Omara, S., TahIawi, R. and Abd El-IS&em, H. 1973. Detailed geological mapping of the area between the latitudes of Sohag and Girga, East of the NIIe Valley, Bull Fat. Eng.. Asstut. University, 1,149-166.

0ma.m. S., El-TahlawI, R. and Shama, K. 1974. Detailed geok@caI mappIng of the Desert area, between ManfaIut and Dairut, Upper Egypt. Bull. Sot. GeograPh Cairo.

Omara. S. and Kenawy. A. 1975. Newly recorded larger foraminifera from the Early Eocene rocks of GabaI Urn El Ghanayem, Kharga Oasis, Egypt. Mitt, Bayer StaatssmmI Pakcmt. Hi&. Gtd. 16.3-18. Munchen.

SnaveIy, D.. Garrison, E. and Meguid, A 1979. Stratigraphy and regional depositional history of the Thebes Formation (Lower Eocene). Egypt. Ann. Geol. Surv. Egypt, Ix, 344-362.

Said, R. 1960. Planktonic foraminifera from the Thebes Formation, Luxor, E@-pt, MfcropaI., 18227-286.

Said, R. 1961. Tectonic framework of Egypt and its influence on distribution of foraminifera. Am Assoc. Petrol. Ged. Bti. 46, 198-218.

Said, R . and Kerdany, M. T. 196 1. ‘lhe geologv and micropaIeontology ofthe Farafra Oasis, Egypt, MfcropaZ, 7, No. 3, 317-336.

Said, R. lQ62. The Geology of Egypt. Elsevier Pub. Comp. Ames&dam, New York

Said, R and Sabry, H. lQ64. Planktonic foraminifera from the type kzality of the Esna Shale in Egypt. M&r-o@. 10(3), 375-395.

Said, R 1971. Explanatory notes to accompany the geological map Of~Egypt. 1:2 060 000. The GeoIog&I Survey of J&pt. St% p. 123.

SaIim, A. S. 1973. Geological studies on Nag’Hammadi area. M.Sc. Thesis, Dept. ofGeology, Assiut University.

Schaub. H. 1951. StraUgraphie und Palaontolagie des Schlier, enilysches mit besonderer Berucksichtigung der paleocaenen unduntereocaenen NummuIiten und AssiIinen. Schweiz. Pal. Abh, 68.222 p.

Youssef, M. M.. Mansour, H. H., Phflobbos, E. R. and Osman, 2. L. 1982. Contribution to the geology of the area north-west ofAssiut. Egypt. BuZL Fat. Set, Assiut University, 11(l). 335-354.

Zittel, K. 1883. BeitrangezurGeologieundPaleontoIogie der libyschen Wuste Und der angrenzenden Gebiete von Aegypten: PcdeontugraPftica. Stuttgad 30. I- 112.

litho- and biostratigraphy of the lower eocene carbonate sequence in upper egypt: evidence for...

Documents