Unusual Factor Affecting the Preservation of Fossils from Northen

ence Sci & C h li rt m a a E t i f c Mekawy, J Earth Sci Climate Change 2012, 3:3 Journal of

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r DOI: 10.4172/2157-7617.1000121

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J Earth Science & Climatic Change ISSN: 2157-7617

Research Article OpenOpen Access Access Unusual Factor Affecting the Preservation of Fossils from Northern Sinai, Egypt Manal S. Mekawy* University of Suez Canal, Department of Geology, Ismailia, Egypt

Abstract The preservational quality of fossils varies greatly from place to place, due in part to variation in factors such as sedimentary environment, diagenetic processes and taphonomic conditions. High-quality preservation of marine invertebrate animals is often associated with rapid burial in sediment. Depositional environments with high sedimentation rates are often associated with tectonic deformation (folds and faults). For example, the Syrian Arc System has formed a highly folded and deformed tectonic regime in the northern Sinai Peninsula. The resulting heavy sedimentation rates in the adjacent Tethys Sea produced thick packages of fossiliferous (sandstones, mudstones, limestones) during the Cretaceous. This study details the tectonic context of the abundant and well-preserved marine invertebrate faunas in the northern Sinai, of Egypt, focusing on the Gebel Yelleg and Gebel Mistan sites.

Keywords: Rock; Deformation; Cretaceous; Fauna; Sediments through Cretaceous carbonates, which were deposited on a shallow platform that deepened towards an open Tethys Sea to the north [5]. Introduction The Jurassic and Cretaceous sedimentation of north and central Sinai Fossils, the preserved remains or evidence of past life, are the direct Peninsula was cyclical and controlled by the clastic supply from the means of documenting the history of life on Earth [1]. Preservation can Arabian-Nubian Shield, the eustatic sea level, and local and regional be highly variable from place to place, so palaeontologists commonly tectonics [5]. The Early Cretaceous was marked by sharply accelerated target the particular regions and environments that were characterized continental rifting activity, as evidenced by the development of by a relatively continuous sediment accumation and by postmortem dominantly E-W trending grabens in northern Egypt and northeastern conditions that favoured to fossil preservation [2]. Accordingly, Libya [6]. The rift tectonics seems to have terminated at the end of the numerous palaeontologists studied the fossils of the Sinai Peninsula, Early Cretaceous. During the early Late Cretaceous (Cenomanian), the especially in northern part because this region is one of the best fossil North African margin was widely transgressed by the Neo-Tethys [7]. sites in Egypt, yielding well preserved specimens of Cretaceous time In central Sinai, Cenomanian sediments are predominantly formed by that most of them represent a shallow, near shore environment. marls and shales, whereas in northern Sinai carbonates are increasingly common. Turonian shales, marls, limestones, and sandstones were The present work focusses on the relationship between rock deposited conformably on the Cenomanian beds. In northern and deformation and the preservation of Cretaceous macro-invertebrate central Sinai, the Senonian deposits are predominantly chalks [6]. fauna from two northern Sinai sites in Egypt: Gebel Yelleg and Gebel Mistan (Figure 1). The main goal of this work is attempt to Gebel Yelleg explain presence of abundant and well-preserved marine Cretaceous Gebel Yelleg is located in the northern Sinai of Egypt at 33°15´- macrofauna of northern Sinai despite the rock deformation found and 33°47´ E and 30°15´-30°36´ N. This site is a large, elongated asymmetric to stimulate further research on this interesting subject. dome of Cretaceous rocks ranging from pre-Cenomanian rock (Lower Geological Setting Cretaceous sand stones) to Campanian Chalk [8]. The Cretaceous rock units from base to top are the Galala formation (422 m) (Late In this work, the author selected Gebel Mistan and Gebel Yelleg Albian-Late Cenomanian), the Wata Formation (102 m) (Early-Late sites in northern Sinai, Egypt, to achieve the goal of the present study Turonian), the Themed Formation (15 m) (Coniacian-Santonian), and (Figure 1). The Sinai Peninsula (Figure 1) is triangular in shape and the Sudr Chalk (Campanian- Maastrichtian) [9-11]. occupies an area of nearly 6000 km2. The geology of Sinai Peninsula ranges from Precambrian basement rocks to Quaternary sediments. Gebel Mistan The southern sector of the peninsula is occupied by rigid Precambrian Gebel Mistan is located at 33°30´-33°40´E and 30°45´-30°55´N. basement rocks, while the central and northern sectors are covered with This site is one of the hills comprising Gebel Maghara proper [8]. Gebel a north-ward-draining limestone plateau with a series of northeast- trending anticlinal and synclinal gables. These folds, extending from the Western Desert in the west to Jordan and Syria in the east, follow the Syrian Arc System [3]. *Corresponding author: Manal S. Mekawy, University of Suez Canal, Department of Geology, Ismailia, Egypt, E-mail: [email protected] The Sinai Peninsula is bounded by rocks that were deposited in the Tethys Sea, by the Oligo-Miocene Gulf of Suez rifted basin to the Received August 25, 2012; Accepted October 08, 2012; Published October 11, west, and by the Late Miocene to recently transformed Dead Sea-Gulf 2012 of Aqaba rift to the east. Each of these major elements has dramatically Citation: Mekawy MS (2012) Unusual Factor Affecting the Preservation of Fossils affected the structure and tectonic evolution of the northern Sinai area from Northern Sinai, Egypt. J Earth Sci Climate Change 3:121. doi:10.4172/2157- [3], an area that is highly folded and deformed due to the Syrian arc 7617.1000121 system [4]. The hills, including the Gebel Maghara, Gebel Halal, and Copyright: © 2012 Mekawy MS. This is an open-access article distributed under Gebel Yelleg, are the expression of doubly plunging anticlines with the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and axial surfaces striking northeast-southwest. These folds affect Jurassic source are credited.

J Earth Sci Climate Change ISSN:2157-7617 JESCC, an open access journal Volume 3 • Issue 3 • 1000121 Citation: Mekawy MS (2012) Unusual Factor Affecting the Preservation of Fossils from Northern Sinai, Egypt. J Earth Sci Climate Change 3:121. doi:10.4172/2157-7617.1000121

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33˚25` 33˚ 45` 33˚ 30` 33˚ 35` 33˚ 40` G. Risan Aneiza Mediterranean Sea N

Raghawi 31˚ Risan Aneiza Maghara 30˚ 55` Mistan Halal Yelleg Arief El Naga Suez G. Amrar 30˚ Themed Sinai

Gulf of Suez Gulf of Aqaba of Gulf G. Umm Mafruth 30˚ 50` 29˚ W. El Ghaib Ekma

G. Mistan

28˚ 33˚ 35˚ G. Raghavi 32˚ Wadi El-Fath G. Umm Asagil

30˚ 45`

G. Maghara 30˚ 40` G. Manzour

G. Maaza

30˚ 35`

30˚ 30`

G. Yelleg

30˚ 25`

Wadi El-Hassana

Risan Aneiza Formation (Barremian-Albian) Campanian-Masstrichtian Malha Formation (Barremian-Albian) Coniacian-Santonian Jurassic Normal fault Wata Formation (Turonian) 0 5 10 km Plunging anticlines Halal Formation (Albian-Cenomanian) Studied sections

Figure 1: Location map of the study area.

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Mistan is a part of the great Maghara Dome in northern Sinai and level of genera based on the studies of El-Qot [15], and Mekawy [13] ranges in age from Upper Aptian to Cenomanian (incomplete) [12- (the present author) For more details refer to [15]. In Gebel Mistan, 15]. Gebel Mistan is subdivided from base to top into the Malha, Risan the recorded macrofauna in table 2 based on the studies of Mekawy Aneiza (160 m), and Halal (140 m) formations [13]. (the present author) and Abu-Zeid [13] (for bivalves and gastropods) and Hamama, 2010 (for ammonites) and personal field observations Field Observation and Types of Fossil Preservation (for corals and echinoids). The stratigraphic columnar section of the The study area is characterized by high abundance of Cretaceous Cenomanian and Turonian rocks of Gebel Yelleg shown in figure 2 macro and micro- marine faunas with good preservation. Gebel while the stratigraphic columnar section of the Upper Aptian-Albian Yelleg represents Upper Cretaceous fauna while Lower Cretaceous rocks of Gebel Mistan shown in figure 3. fauna are concentrated in Gebel Mistan. In Gebel Yelleg the author Gebel Yelleg fauna focused on Cenomanian and Turonian macrofauna and table 1 show some of the recorded Cenomanian and Turonian macrofauna on the Gebel Yelleg is a highly fossiliferous sites with diverse of marine

Age Formation Macro-fauna genera bivalves gastropods ammonites echinoids Late Curostrea, Pholadomya , , Turonian Middle Curostrea, Praeradiolites, Durania, Pholadomya Turritella, Tylostoma, Coilopoceras Phymosoma Coenholectypus Petalobrissus Wata Formation ,

Early

Phelopteria, Curostrea, Tylostoma, Thomasites, Choffaticeras, Petalobrissus Hemiaster

, Late Brachidontes, Barbatia, Cucullaea, Nayadina Costagyra, Ceratostreon, Ilymatogyra, Rhynchostreon, Ambigostrea, Rastellum, Chondrodonta, Cimolithium, Nerinea, Neolobites, Micopedina, Heterodiadema, Coenholectypus

Middle Barbatia, Nayadina, Ceratostreon, Ilymatogyra, Rhynchostreon, Chondrodonta, Praeradiolites, Lucina, Nerinea, Aptyxiella , Aporrhais, Pterodonta, Pterocera, Ampullina, Tetragramma , Coenholectypus Cenomanian Galala Formation Early , Plagiostoma, Nucula, Inopera, Barbatia, Pseudoptera Ceratostreon,Rhynchostreon,G yrostrea, Chondrodonta, Eoradiolites,Maghrebella Aporrhais, Pterodonta, Pterocera, Ampullina Tetragramma, Goniopygus, Coenholectypus Hemiaster

Table 1: Upper Cretaceous macro-fauna genera that recorded from Gebel Yelleg.

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Age Formation Macro-fauna species Corals gastropods bivalves ammonites echinoids Late Petrocera incerta, Colombellina fusiformis, Drepanocheilus muli,Pleurotomaria neocomiensis Protocardia hillana, Pinna robinaldina, Pholadomya gigantean, Chlamys goldfussi, Glossus aquilinus Halal Middle Albian Acteonella delgadoi, Drepanocheilus magharensis, Ampullina prolonga, Glauconia deserti, Nerinea abbassi Ceratostreon flabelatum, Neithea quinquecostata

Early Diastoma ornate, Aneiza Ampullina ervyna, Nerinea mistanensis, Pseudomesalia deserti, Riselloidea tricarinata, Turriscala darwishi Nucula magaritifera, Maghrebella deserti, Corbula magharensis, Modiolus manzourensis, Cameleopha pharaonis Teragonaites nautilodes aff. aff. sp. sp. sp., Discotectus sp. sp ., Spharea corrugate, Late Aptian sp. ,Paracycloseris sp. ,Trochosmilia Risan Epistreptophyllum manzourensis, Epistreptophyllum cretacea,Mixastraea sp. ,Stylina regularis, Montlivaltia zuercheri, Uhligella clansayensis, Phylloceras moreti, Teragonaites nautilodes, Teragonites heterosulcatus, Teragonites Hemiaster sp ., Coenholectypus Turritella mordi, Nerinea magharensis, mistanensis, Tylostoma magharensis,Tylostoma globosum, Pyrazus magharensis,Pyrazus sexangulatus,Pseudomesalia quadrilineata, Pseudomesalia deserti, Ampullina ervyna, Gervillaria alaeformis, sowerbyana,Gervillaria Ptychomya robinaldina, Trigonia undulatocostata, Cucullaea orintalis, Pterotrigonia scabra Valdedorsella akuschense, Zuercherella

Table 2: Lower Cretaceous macro-fauna species that recorded from Gebel Mistan. macro-invertebrate fauna, especially in the Cenomanian and Mistan are very well preserved especially those that occur in shales Turonian rocks. Most of them show low degree of disarticulation and carbonates where those that occur in chalky limestone and and fragmentation. Skeletal remains are randomly oriented, relatively dolomitic limestone are not well preserved. Assemblages are densely poorly sorted and oysters and rudists occur in clusters and in growth packed, moderately sorted, randomly oriented, with low degree of position. They do not show any signs of deformation or compaction. disarticulation and fragmentation. Most of the shells were preserved The most common taxa are represented by bivalves (such as oysters, in life position and no folded and deformed fauna is found. The rudists), followed by gastropods (such as Turritellidae, Nerinea, most common macro-invertebrate fossils are represented by bivalves Tylostoma), echinoids (such as Hemiaster, Coenholectypus), and (such as Gervillaria, Trigonia, oysters), followed by gastropods (such cephalopods (such as ammonites, nautiloids) (Figure 4). The site also as Nerinea, Tylostoma, Pyrazus) Mekawy and Abu-Zeid [13], and yields microfauna such as foraminifera and ostracods [15]. ammonites (such as Barremites, Phylloceras, Tetragonites) [14]. Brachiopods, colonial and solitary corals are common in the lower part Gebel Mistan fauna of Gebel Mistan and can be found scattered on the surface (Figure 5). Lower Cretaceous assemblages (Upper Aptian- Albian) of Gebel Foraminifer microfossils have been recorded at Gebel Mistan [12].

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Bed Larger f.Macro Biozones Bed Stage Fm Lithology Mb. Lithology Ammonite Zones Biozones based on other macro- No. Stage Fm No. fossils 23 59 Pycnodonte ( Phygraea ) vesicularis Ca. Sd. P. (C.) costei - O. dichotoma - P. ferryi P. 58 cretacea 57 Cucullaea (Idonearca) maresi Middle 22 56

Conc.-San.? Middle Themed 55 Metatissotia ewaldi Coilopoceras U. 54 requienianum 21 53 20 52 51 19 50 upper carbonate 49 Durania arnaudi - Praeradiolites 48 ponsianus aegyptiacus - Legend 47 Praeradiolites irregularis 46 18 Middle 45 Sandy dolostone Gyrostrea 44 Phymosoma abbatei - Tylostoma (T.) globosum delettrei - Turonian Rhynchostreon

Wata Formation Wata 43 suborbiculatum - Dolostone Hemiaster

middle clastic 42 17 (Hemiaster) Hemiaster (M.) heberti turonensis - gabrielis 41 Coenholectypus turonensis Dolomitic limestone 16 40 Argillaceous limestone 39 Choffaticeras segne 15 Lower Thomasites rollandi Sandy limestone Lower lower carbonate Cenomanian Pycnodonte ( Phygraea ) vesiculosa - 38 Rastellum carinatum Limestone 14 37 Costagyra olisiponensis Sandstone Galala Formation 13

36 Siltstone Upper 12 Eoradiolites 24m liratus Ambigostrea pseudovillei - Shale llymatogyra africana 16m 35

34 Marl 8m 11 33 Neolobites Chalk 0 32 vibrayeanus 10 31 30 9 29 Chalky limestone

8 Galala Formation Cenomanian 28 7

6 27

5 0. conica 26 Nerinea gemmifera - Praeradiolites biskraensis Middle

4 Ceratostreon flabellatum - 25 3 Pterocera Upper

Albian incerta 2

1 24 ? Mal

Figure 2: Stratigraphy of the Upper Cretaceous succession exposed at Gebel Yelleg, North Sinai, Egypt (after Abdel-Gawad et al., 2004).

Results and Discussion and diversity of marine organisms, may be responsible for a quick cover of fauna by sediments and therefore good preservation. The The low degree of disarticulation and fragmentation, relatively well-preserved organisms must have been embedded by rapid burial. poor to moderate sorting, randomly orientation of organisms in life The animals buried in this way were most likely alive in many cases position suggest that the fossil assemblages at both sites were quickly and may have been killed by the effect of tectonic movement, which covered with sediment, possibly while some of them were still alive would explain the dominance of marine fauna with a large proportion which may be due to the tectonic movements. The absence of deformed of complete specimens and good preservation. fossils may support the idea that the deformation of Cretaceous rocks took place during the life of the fauna. Finally, the discussion above may be explaining the presence of The Cretaceous sedimentary rocks of northern Sinai represent fossils in a well-preserved condition in northern Sinai despite the rock one of the thickest sequences in Egypt due to the transgression of the deformation found. Neo-Tethys (previous studies). The thickness and the bedded nature of Conclusions the sedimentary rocks make it easily deformable into faults and folds. The time of deformation in the northern part of the Syrian arcand 1) The northern Sinai is highly folded and deformed dueto northern Sinai in the Cretaceous, which coincided with an abundance geomorphic effects of the Syrian arc system.

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2) The present study details the relationship between northern a b Sinai’s tectonic regime and the preservational quality and completeness of two marine invertebrate faunas: Gebel Yelleg (Upper Cretaceous) and Gebel Mistan (Lower Cretaceous). 3) Marine invertebrates observed in the study area are well preserved and in life position, with low degrees of disarticulation and fragmentation, random orientations, and moderate to c d poor sorting; no folded or deformed fossils have been found. 4) Taphonomic conditions of the studied faunas suggest rapid

e f

Age

Samples

Formation

Bed no. Bed Lithology

66 100 m

65 65 Upper Alb Upper 64 64 55 54 53 Figure 5: Deformed rocks of Gebel Mistan (A), Aptian corals from Gebel Mistan (B), Aptian Nerinea bed from Gebel Mistan (C), Albian Nerinea bed 48 48 50 m from Gebel Mistan (D), Albian rudist bed from Gebel Mistan (E), Albian ammonite from Gebel Mistan (F).

Halal 43 Middle Albian Middle 38 38 burial by sediments, potentially resulting from regional 0.0 m 36 36 tectonic deformation associated with high erosion rates. 35 34 34 The arrow pointing to the study beds 5) The absence of folded and deformed fauna in the study area 31 31 30 30 Sandstone Dolostone supports the author’s hypothesis that sediment deposition 28 28 Crossbedded Marl occurred while the fauna was still alive. 27 27

Lower Albian Lower sandstone 26 26 Shale Ammonites 25 25 Acknowledgments 24 Bivalves Risan Aneiza Risan 24 Limestone 18 18 Thanks to everyone in Journal of Earth Science & Climatic Change who has Oysters Corals 14 14 contributed toward the progress of this work especially Gracia S. Oliver, Assistant 13 13 Managing Editor to respond to any request I asked her. I am deeply grateful to 11 11 Rudists Echinoids Kathleen S. Lyons, Action Editor, Department of Paleobiology, and University of 7 7 Gastropods Orbitolines Upper Apt Upper 6 6 1 1 New Mexico, USA for critical review of the manuscript. Deep and grateful thanks to Sims HJ and Adam Tomasovych, Geology Institute, Slovak Academy of Sciences, Figure 3: Stratigraphic columnar section of the Lower Cretaceous of Gebel Slovak Republic for their critical review of the manuscript and useful comments. Mistan, North Sinai, Egypt. Refferences 1. Stringer G L (2002) Fossils from the Cane River Site, North-central Louisiana. a b Louisiana Geological Survey, Public information Series No.10. 2. Kidwell S M, Holland S M (2002) The quality of the fossil record: Implications for evolutionary analyses. Annu Rev Ecol Syst 33:561-588.

3. Alsharhan A S, Salah M G (1996) Geologic setting and hydrocarbon potential of north Sinai, Egypt. Bulletin of Canadian petroleum Geology 44:615-631.

4. Aita S K, Bishta A Z (2009) Geology and radioactivity of Gabal El Minsherah-El c d Hasanah District, northern Sinai, Egypt. Egyptian Journal of Remote Sensing and Space Science 12:149-164.

5. Jenkins D A (1990) North and Central Sinai. In: Said, R (Edn), the Geology of Egypt. Balkama, Rotterdam 51-59.

6. Abd El-Motaal E, Kusky T M (2003) Tectonic evolution of the intraplate s-shaped Syrian Arc Fold-Thrust Belt of the Middle East Region in the context of Plate Tectonics. The third international conference on the Geology of Africa e f 2:139-157.

7. Dercourt J, Ricou L E, Vrielynck B (1993) Atals Tethys palaeoenvironmental maps. Gauthier-Villars, Paris 1-307.

8. Moon F W, Sadek H (1921) Topography and Geology of Northern Sinai. Part 1. Petrol Res Bull 10:1-142.

9. Abdel-Gawad GI, El Sheikh HA, Abdelhamid MA, El Beshtawy MK, Abed MM, Figure 4: Deformed rocks of Gebel Yelleg (A-C), Cenomanian oyster beds Fürsich FT, et al. (2004) Stratigraphic studies on some upper Cretaceous from Gebel Yelleg (D & F), Cenomanian rudist bed from Gebel Yelleg (E). successions in Sinai, Egypt. Egyptian J Paleontol 4:263-303.

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10. Mekawy M S (2007) Taphonomy of Cenomanian oysters from Gebel Yelleg, 13. Mekawy MS, Abu-Zied RH (2008) Lower Cretaceous molluscan fauna from North Sinai, and Egypt. Egyptian J Paleontol 7:335-348. North Sinai, Maghara area, Egypt. Egyptian J Paleontol 8:291-334.

11. Mekawy M S (2010) Factors affecting the behavior and trait of some 14. Hamama H (2010) Barremian and Aptain Mollusca of Gabal Mistan and Gabal Cenomanian oysters from Sinai, Egypt. Egyptian J Paleontol 10:107-121. Um Mitmani, Al Maghara Area, Northern Sinai, Egypt. Journal of American Science 6:1702-1714. 12. Said R, Barakat MG (1957) Lower Cretaceous foraminifera from Khashm el Mistan, northern Sinai, Egypt. Micropaleontology 3:39-47. 15. El Qot G M (2006) Late Cretaceous macrofossils from Sinai, Egypt. Beringeria 36:3-163.

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