Southern Tethyan Research Articles

Paleoenvironmental Conditions and Factors Controlling Organic Carbon Accumulation during the Jurassic–Early Cretaceous, Egypt: Organic and Inorganic Geochemical Approach

The Jurassic–Early Cretaceous was a time of variable organic carbon burial associated with fluctuations of marine primary productivity, weathering intensity, and redox conditions in the pore and bottom water at paleo-shelf areas in north Egypt. This time interval characterized the deposition of, from old to young, the Bahrein, Khatatba, Masajid, and Alam El Bueib Formations in the north Western Desert. Although several studies have been devoted to the excellent source rock units, such as the Khatatba and Alam El Bueib Formations, studies on paleoenvironmental changes in redox conditions, paleoproductivity, and continental weathering and their impact on organic carbon exports and their preservation for this interval are lacking. This study presents organic and inorganic geochemical data for the Jurassic–Lower Cretaceous sediments from the Almaz-1 well in the Shushan Basin, north Western Desert. A total of 32 cuttings samples were analyzed for their major and trace elements, carbonates, and total organic carbon (TOC) contents. Data allowed the reconstruction of paleoenvironmental conditions in the southern Tethys Ocean and assessment of the changes in paleo-redox, paleo-weathering, and marine primary productivity, and the role of sediment supply. Additionally, factors that governed the accumulation of organic matter in the sediment were interpreted. Results showed that the Khatatba Formation was deposited during a phase of enhanced marine primary productivity under prevalent anoxia, which triggered enhanced organic matter production and preservation. During the deposition of the Khatatba Formation, significant terrigenous sediment supply and continental weathering were followed by a limited contribution of coarse clastic sediment fluxes due to weak continental weathering and enhanced carbonate production. The Bahrein, Masajid, and Alam El Bueib Formations were deposited during low marine primary productivity and prevalent oxygenation conditions that led to poor organic matter production and preservation, respectively. A strong terrigenous sediment supply and continental weathering predominated during the deposition of the Bahrein Formation and the lower part of the Alam El Bueib Formation compared to the limited coarse clastic supply and continental weathering during the deposition of the carbonate Masajid Formation and the upper part of the Alam El Bueib Formation. Such conditions resulted in the enhanced dilution and decomposition of labile organic matter, and, thus, organic carbon-lean accumulation in these sediments.

Jurassic–Cretaceous intraplatform basins from NW Sicily fold and thrust belt: Implications for oblique rifting of the Southern Tethyan margin

Carbonate intraplatform basins are documented worldwide as peculiar synsedimentary tectonic features forming in rifted margins and especially in those cases where the direction of extension is oblique with respect to the rift axis. A detailed stratigraphy and facies analysis combined with subsidence history of the Upper Triassic-Cretaceous shallow-water carbonates outcropping in the Peninsula of Capo San Vito, representing the NW end of the Sicilian fold and thrust belt, has been performed. Three different sections, separated by faults and characterised by shallow-water and deep-water carbonate sedimentation, were distinguished. Their location and tectonic relationships highlight the occurrence of two structural highs (Monaco and Sparagio sections) separated by a structural low (Acci section).The Acci intraplatform basin, structured since the Pliensbachian, is characterised by mostly pelagic sedimentation with resedimentation of carbonate reef derived-elements from adjacent carbonate platform blocks. On the two structural highs, shallow-water sedimentation, since the Late Triassic, developed with progradational trends shedding out shallow-water elements towards the basin. The evolution of the narrow Acci intraplatform basin appears influenced by a transtensional regime creating a wedge-shaped basin. Backstripping analysis on the three measured sections was able to reconstruct subsidence curves, from which different evolutionary stages, marked by punctual synsedimentary tectonic activity, can be highlighted for the Late Triassic-Eocene time interval.Comparison with the adjacent basin system of Cala Rossa, located 30 km away eastward in the Palermo Mountains, allowed to recognise similar characteristics. The stratigraphic, sedimentologic and tectono-sedimentary common features, trend and kinematic of the paleofaults, and the same chronology of tectonic events, suggest that the two areas represent adjacent basins making part of a unique spindle-shaped basin system. Some variable evolutionary characteristics among the Acci and Cala Rossa basins, including the overall thicknesses, the thickness of the resedimented deposits, the occurrence of Upper Cretaceous shallow-water deposits only in the structural highs of the Acci Basin, are explained as features linked to the different location of the two basins with respect to the master fault. Many of the observed features are described from those rift systems where the direction of extension is not perpendicular to the rift axis, suggesting that this sector of the Southern Tethyan margin could be developed as an oblique rift system.

Revised planktic foraminiferal biostratigraphy of the early late Albian of northern Tunisia (southern Tethys)

The upper Albian exposed near the Imbrication Zone of northern Tunisia is composed of a pelagic sequence that includes organic-rich beds. High-resolution biostratigraphy based on planktic foraminiferal bioevents across marker beds (i.e., organic-rich beds), allows revision of the lithostratigraphic subdivision and zonal scheme in comparison with late Albian time equivalents recorded in the northern Tethyan margins. In the present study, we proposed a new subdivision of the upper Albian lithostratigraphic section that now includes the Mellegue horizon as an equivalent of theAmadeus Segment rhythmic marl/limestone interval (central Italy). Three studied sections are subdivided into five biozones with the abundance and morphological trends of planktic foraminifera and inferred paleoenvironments: 1) The Biticinella breggiensis Total Range Zone is characterized by the appearance of ticinellids with pinched chambers (i,e., Ticinella praeticinensis) and is recorded a few meters above the first occurrence of Biticinella breggiensis. Agradual increase of trochospiral thick-walled (B. breggiensis, T. roberti, T. raynaudi) and Globigerinelloides taxa, reflecting mesotrophic conditions. 2) The Pseudothalmanninella subticinensis Interval Zone includes the first appearance of keeled forms (Ps.subticinensis), associated with abundant ticinellids with flattened chambers (B.breggiensis, T. roberti) below the base of the organic-rich Mellegue horizon, indicating an oligotrophic environment. 3) The Pseudothalmanninella ticinensis Interval Zone. The continuous occurrence of T. primula and the scarcity of Globigerinelloides throughout the lower part of this zone indicates an oligotrophic to weakly mesotrophic environment. The occurrences of radiolarian-rich horizons and abundant forms with elongated chambers (T. raynaudi) in the lower part of this zone indicate an abrupt shift to enhanced eutrophic and dysaerobic conditions. 4) The Thalmanninella appenninica Zone, which shows a decrease in abundance preceding the extinction of ticinellids, and a gradually increasing number of specialized keeled forms (i.e., Th. appenninica), indicates oligotrophic conditions. 5) The Planomalina buxtorfi Total Range Zone is characterized in its lower part by an increasing abundance of clavate forms with radially elongated chambers (i.e., Clavihedbergella) above the organic-rich bed of the Mouelha Member, indicating low-oxygen, oligotrophic to mesotrophic conditions.

Palaeocene to Miocene southern Tethyan carbonate factories: A meta‐analysis of the successions of South‐western and Western Central Asia

AbstractOne hundred and forty‐four published successions of shallow‐water carbonates, deposited between the Palaeocene and the Miocene, from the Levant to the Himalayas, have been re‐analysed using a standardised approach to investigate the distribution of carbonate facies and carbonate‐producing organisms. Large benthic foraminifera were found to be the volumetrically most important group of carbonate producers during the whole period, with a peak in abundance during the Eocene. Colonial corals are relatively abundant during the Palaeocene and Miocene, their abundance peaks during the Oligocene and has a minimum during the Eocene. Red calcareous algae have a similar pattern although their peak in abundance covers both the Oligocene and Miocene. Green calcareous algae decrease from the Palaeocene onward. Facies related to very shallow and/or restricted marine conditions peak during the Miocene and in particular during the Aquitanian. Both the pattern of large benthic foraminifera and of colonial corals seems to be related to temperature, with warm periods favouring the former group and cool periods the latter group. Red calcareous algae display a pattern similar to that of colonial corals suggesting that the periods favourable for one group are, on a large scale, also favourable for the other. The progressive decrease of green calcareous alga could be tentatively related to a preservation bias connected to the transition from Palaeogene assemblages that included presumably calcitic taxa of green algae to Neogene assemblages entirely constituted by aragonitic taxa with limited preservation potential. The Aquitanian peak in facies related to very shallow and/or restricted marine conditions is most likely connected to the progressive narrowing of the Tethys related to the collision between Arabia and Eurasia. These results denote an overall agreement between the abundance of the various types of shallow‐water carbonate facies and large‐scale environmental and geological processes, highlighting the potential for palaeoenvironmental reconstruction locked in the shallow‐water record.

Ostracods sensitivity to reconstructing water depths and oxygen levels: A case study from the Middle-Late Eocene of the Beni Suef area (Egypt)

Fifty-five ostracod species have been identified from 100 samples belonging to three stratigraphic sections in the Middle-Upper Eocene strata of the Beni Suef area (southern Tethys of Egypt). These ostracods have been used to subdivide the studied time interval into three zones that are correlated to the planktic foraminiferal zones E13 to E15. Based on clustering, non-metric Multidimensional Scaling (nMDS), and The Permutational MANOVA, sediment facies was found to be a significant factor controlling the ostracod fauna. Four assemblages were identified and their bio-ecological preferences were used to reconstruct paleoenvironments: 1) The upper Bartonian ostracod assemblage (El Fashn Formation) is dominated by Paracypris eskeri Bassiouni and Morsi and Novocypris eocenana Ducasse and is characterized by lower Shannon Diversity and higher ‘Dominance’ of stenohaline species with preference for lower oxygen levels and deeper neritic water depths; 2) The uppermost Bartonian (Qurn Member of Beni Suef Formation) is dominated by Paracypris eskeri Bassiouni and Morsi and Bairdia gliberti (Keij) indicating better oxygenated environmental conditions, supported by higher diversity values; 3) The lower Priabonian (Tarbul Member of Beni Suef Formation) is dominated by Novocypris eocenana Ducasse and has the lowest diversity, linked to the significant decrease of species with preference for highly oxygenated conditions; 4) The uppermost Priabonian (Maadi Formation) contains the most diverse assemblage and is characterized by a very low ‘Dominance’ and very high Shannon Index, where 26 species constitute the trophic nucleus and most of them are indicative of shallow water-depths and inner shelf settings in addition to preferences for high oxygen levels. The general increase in diversity and decrease in dominance is attributed to improved environmental conditions at shallower depths, where enhanced water mixing increased the oxygen available for biological demands. Moreover, the strong similarity of the recorded ostracod assemblages with those reported from other southern Tethyan sites reflects migration through the Atlantic and/or the trans-Sahara seaway, while the low similarity with the northern Tethys province (Europe) may be related on the one hand to their benthic nature, which may have limited their ability to move for longer distances, on the other hand to prevailing cooler waters to the north at higher latitudes. Water depth and associated environmental changes in respect to oxygen levels is interpreted to be the main factor controlling the distribution of the ostracods in the Beni Suef area.

Aptian−Albian extension in Tethyan rifted continental passive margin of Tunisia inferred from sequential restorations of balanced cross-sections and expansion index

This article presents an overview of regional extensional deformation across the north-facing southern Tethyan continental passive margin of Tunisia during the Aptian and Albian syn-rift stages. Because of the Late Eocene, Late Miocene and Pleistocene orogenic overprinting, the earlier extensional history of the Tunisian Atlassic province had to be reconstructed from balanced and sequentially restored transects across four key fault systems active at the time. These were used to (i) estimate the amount and timing of extension and (ii) calculate the expansion index (EI) for each fault system. The analysis demonstrates the region experienced a very significant amount of mid-Cretaceous extension, representing the last of several Permian-Mesozoic rift events. Two closely linked styles of deformation were recognised: thick-skinned basement involved faulting and shallow listric faulting detached on decollement surfaces within late Triassic evaporites. Both styles of faulting triggered salt diapirism.Sequential pre-orogenic restorations of a transect across the Tebaga Kebili and Orbata faults in the southern part of this province suggest both experienced a large amount of extensional displacement during the Aptian and Albian (Aptian-Albian extension = 2.6 km), recorded by footwall erosion, growth strata, rollover structures and changes in sedimentary facies. A similar restoration across the Labaiedh (M'rhila-Cherichira) fault system further north, identified both thick and thin-skinned extensional movement associated with diapiric growth and salt extrusion reaching a maximum during the Aptian (Aptian-Albian extension = 0.55 km). A pre-Tertiary restoration of the Teboursouk fault system in the northern part of the province, demonstrated thick-skinned extension peaking during the Albian (Aptian-Albian extension = 0.4 km). This accommodated a thick sequence of basinal shales to the north, deformed by active diapirism with sea-floor salt extrusion, triggered by deep basement faulting and enhanced by the plastic incompetent character of the thick shale dominant overburden.Regional extension across the Tunisian Atlassic province during the Aptian-Albian was contemporaneous with a significant change in intra-plate stress across northern Africa, the opening of the South Atlantic and structural reorganization along the East African continental margin. This synchroneity across such a wide region may reflect some still poorly understood deep crustal processes, ultimately responsible for reactivating older rift faults and regional tilting across the province. The associated gravity salt gliding and diapirism bear comparison with the post-rift deformational style of the South Atlantic passive margin. However intra-evaporite decollement surfaces were more local, limited by active thick-skinned faulting with diapirism typically soft linked to deeper fault movement.

Sedimentology and New Paleo-geographic Data of the Upper Cretaceous-Lower Paleocene Haria Formation in the Gafsa Basin (Tunisia) Southern Tethyan Margin

Abstract Facies associations and environmental evolution of the late Cretaceous–lower Paleocene shallow platform of the Haria Formation (upper Maastrichtian–Danian–Selandian) have been studied from the Gafsa basin, located in southern Tunisia. Four main lithostratigraphic units have been identified. Unit 0, deposited on a restricted platform, is organized into aggradational and shallowing-upward sequences. Unit 1 is composed of shallowingand deepening-upward sequences that are deposited in externally restricted platform environments. Unit 2 is a peritidal shallowing-upward sequences deposited in shallow restricted environments ranging from the intertidal to supratidal environments. Unit 3,is composed of shallowing-upward sequences corresponding to the “muddy” type in the lower part, deposited in the proximal part of the shallow restricted external platform, and the “grainy” type in the upper part, representing wave-dominated bioclastic shoals and channel deposits. The proximal-distal transition of depositional environments gradually ranges from lagoon to offshore environments. Lateral variation of thickness and facies is generated by the reactivation of NW-SE extensive and/or transtensive faults, acting since the late Cretaceous during the intermediate closing phase of the Neotethys. These tectonic features were also expressed by changes in facies. The Haria Formation’s mixed carbonate-marls successions are classified into seven major facies associations, with carbonates considered a new facies represented by channel deposits and lumachellic limestones. This study establishes for the first time a clear and detailed regional stratigraphic correlation and paleogeographic maps based on the new litho- and biostratigraphic data.

The Cenomanian–Turonian Boundary Event (CTBE) as recorded in the northern margin of Africa: palaeoceanography of the Oceanic Anoxic Event (OAE-2), North-Central Tunisia

ABSTRACT Samples spanning the Cenomanian–Turonian transition at Guern Halfaya Section of North-Central Tunisia were analysed for elemental and isotopic chemostratigraphic characterization of the OAE-2 global anoxic event. Comparison with other published sections of the same age was achieved. These geochemical analyses, which cover the local Bahloul Formation, add new insights into the palaeoceanographic evolution of the southern Tethyan margin during the Cenomanian–Turonian transition. The use of discrete redox-sensitive and primary productivity-sensitive trace element data coupled to isotopic and biostratigraphic events is shown as leading proxies for the determination of prevailing warming palaeoceanographic conditions, in terms of productivity and climate, during the OAE-2 in the northern margin of Africa. Such event is believed to have generated one among the most significant source rocks of the region.

Biostratigraphy, palaeoecology, and palaeobiogeography of the Middle–Late Eocene ostracods, north‐west Fayoum area, Egypt

The present study focuses principally on the late Middle Eocene–early Late Eocene ostracods from two successions (Garet Umm Rigl section and Qasr El Sagha sections), in the northwestern portion of Fayoum area, Egypt. Stratigraphically, the studied successions are classified into three formations (from base to top), the Gehannam, Birket Qarun, and Qasr El Sagha (Temple Member). The recorded ostracod assemblage contains 33 species belonging to 20 genera and 9 families. According to their stratigraphic ranges, three local biozones are recognized, Asymmetricythere yousefi–Loxoconcha pseudopunctatella, Reticulina heluanensis–Leguminocythereis sadeki, and Trachyleberis nodosus nodosulcatus–Ruggeria (Keijella) glabella. The comparison of the proposed biozones with their equivalents inside Egypt denotes a Middle–Late Eocene age for the studied sections. Based on the character of investigated ostracods, three ecozones are distinguished. An inner–outer neritic environment is suggested for the first ecozone, inner‐middle neritic conditions for the second, while shallow water conditions are proposed for the third ecozone. In addition, this paper represents an attempt to detect the palaeobiogeographic provinces of Eocene ostracods by means of multivariate analyses (principle component analysis, Q‐mode cluster analysis and similarity index). These analyses are applied on a matrix composed of some selected Eocene species from 10 regions located at the southern Tethys and western Africa. The results identify three distinctive provinces, North Africa (Algeria, Tunisia, Libya, and Egypt), the Middle East (Jordan and Israel) and West Africa (Senegal, Togo, Ivory Coast and Nigeria). The distinctive affinities between these provinces suggests ostracod migration along the southern Tethys during the Eocene age.

Ichnology of the Cenomanian–Turonian boundary event in the southern Tethyan margin (Khanguet Grouz section, Ouled Nail Range, Algeria)

Ichnology of the Cenomanian–Turonian boundary event in the southern Tethyan margin (Khanguet Grouz section, Ouled Nail Range, Algeria)

Increased ocean acidification by upwelling intensification in southern Tethyan margin during the PETM: implication for foraminiferal record

Increased ocean acidification by upwelling intensification in southern Tethyan margin during the PETM: implication for foraminiferal record

A mud-dominated coastal plain to lagoon with emerged carbonate mudbanks: The imprint of low-amplitude sea level cycles (mid-Upper Cretaceous, South Iberian Ramp)

The middle Santonian-lower Campanian carbonate-mud dominated succession deposited in the northeastern margin of the South Iberian Ramp (La Cañadilla Fm, NE Spain) shows a complex set of interfingered facies developed in a low-energy and low-gradient shallow-marine to coastal environment. Three facies belts characterize the environment reconstructed in this work: (1) a low-energy shallow marine lagoon dominated by radiolitid rudist limestones and miliolid-rich facies with variable carbonate-mud content; (2) a transitional belt with a patchy distribution of ponds and mudbanks. This belt mostly consists of miliolid-rich limestones with variable amount of fenestral porosity, which are interfingered with charophytes and gastropod marls and limestones usually mixed with miliolids; (3) a coastal plain with strong freshwater influence characterized by the sedimentation of marls and limestones with charophytes, gastropods and root traces and intraclastic/black pebble limestones. The studied succession is arranged in high-frequency sequences, including meter-scale parasequences bounded by widespread flooding surfaces, which stack in five larger-scale shallowing-upward sequences (6–20 m thick). The time calibration of these sequences obtained from strontium isotopes and biostratigraphic data (benthic foraminifera) suggests a major control in the sedimentation by climate-driven low-amplitude sea level oscillations formed in tune with the long- and short-eccentricity orbital cycles. Cyclic sea level rises controlled the existence of widespread flooding events in the low-gradient carbonate ramp at the onset of parasequences, which in the studied marginal areas of the South Iberian Ramp were mostly sourced from the southern Tethyan realm. Therefore, the La Cañadilla Fm provides an example of a complex shallow marine to coastal system giving rise to a mosaic distribution of carbonate-mud dominated facies, with sedimentation mostly influenced by external factors resulting in a well-defined stratigraphic architecture. The similarities with modern analogous systems such as the Ten Thousand Islands of the Florida Bay are discussed in this paper.

A new Early Triassic brachiopod fauna from southern Tibet, China: Implications on brachiopod recovery and the late Smithian extinction in southern Tethys

AbstractBrachiopods suffered high levels of extinction during the Permian–Triassic crisis, and their diversity failed to return to Permian levels. In the aftermath of the Permian-Triassic mass extinction, brachiopods were extremely rare worldwide, especially in the southern hemisphere. Here, we report a new Early Triassic brachiopod fauna from the Selong section in southern Tibet, China. A new genus and three new species have been identified: Selongthyris plana Wang and Chen n. gen. n. sp., Piarorhynchella selongensis Wang and Chen n. sp., and Schwagerispira cheni Wang and Chen n. sp., which are typical. The ontogenies and internal structures of these three new species are described in detail. This brachiopod fauna corresponds to the Neospathodus pakistanensis and Neospathodus waageni conodont biozones and Kashmirites and Anasibirites ammonoid biozones, indicating a late Dienerian to late Smithian age. The post-extinction recovery of brachiopods in the Himalayas may have begun by the early Smithian of the Early Triassic. In addition, these species did not persist into the Spathian substage, suggesting that the newly evolved brachiopods in the southern Tethys were severely affected by the late Smithian extinction event.UUID: http://zoobank.org/f8fc8ced-432c-41d2-8c6c-d17bca527109

Integrated stratigraphy of the lower Eocene successions on the southern Tethys margin (Egypt): Emphases on the hyperthermal events

The early Eocene is marked by prominent short warming episodes that are globally documented. The present study provides a well-established micropaleontological record of the calcareous nannofossils, planktonic, and benthonic foraminifera in order to evaluate the impact of the environmental perturbations across the early Eocene generally and particularly throughout these short warming events. This study has been conducted on two expanded lower Eocene successions at the Dababiya and the El-Ballas sections, southern Egypt. The recorded benthonic foraminifera indicate a deposition in a middle-outer neritic setting for El-Ballas, while at the Dababiya section, the lower part is deposited in an inner-middle neritic setting that changed upward to middle-outer neritic due to sea-level oscillation. The detailed analyses of the identified calcareous nannofossils and foraminifera allow definition of four early Eocene hyperthermal events. These events are the Post-Paleocene Eocene Thermal Maximum (Post-PETM), Eocene Thermal Maximum-2 (ETM-2), H2, and Eocene Thermal Maximum-3 (ETM-3). These events are indicated by a remarkable shift of the calcareous planktonic warm water indicators. The benthonic foraminifera assemblages that were recorded throughout these events reflect partially dysoxic/suboxic marine conditions associated with increased eutrophication probably of mesotrophic marine conditions. The calcareous planktonic and benthonic foraminifera record indicates evidence of minor dissolution across these events. Unlike the PETM, these events had a lesser impact on the environmental marine condition. The integrated data of the present study show that the magnitude of these events was greater and more pronounced at the shallower site at the Dababiya than at the deeper El-Ballas section.

Contribution to the Paleontology, Stratigraphy and Paleogeography of Ninety-seven Southern Tethian Agglutinated Foraminiferal Species

Ninety-seven Campanian–Paleogene smaller agglutinated benthic foraminiferal species belong to thirty-five genera from ten countries in the Southern Tethys (Algeria, Egypt, Palestine, Jordan, Iraq, Qatar, UAE, Iran, Pakistan, India) have been studied. The modern taxonomical consideration of the species are used. Eighty-nine of the recorded species were previously noted in the literatures, while eight of them are believed here as new: Haplophragmoides iranica, Pseudogaudryinella iraqensis, Arenobulimina beitjebrinensis, A. jerusalemensis, Textulariella sinaensis, Dorothia iranica, Clavulinoides iranica, and Textularia salahii. Forty species of them are recorded from Egypt (about 41%), twenty seven from Pakistan (~28%), ten from UAE (~10.5%), six from Qatar (~ 6%), four from each of Algeria and Iran (~ 4 %), three from each of Jordan (~ 3%), two from each of Palestine and Iran (~2%), and only one from each of Iraq and India (~1%). Most of the Southern Tethyan recorded species are endemic to their original description, while five of them are also recorded in some Northern Tethyan countries (Spain, France, Italy, Hungary and Slovenia): Bathysiphon saidi, Haplophragmoides desertorum, Spiroplectinella esnaensis, Siphogaudryina africana and Textularia crookshanki. The Southern Tethyan assemblage indicate an open marine environment, which represents middle-outer neritic environment (100-200 m depth), and show s an affinity with Midway-Type Fauna 'MTF'' of the United States Gulf Coastal area.

THE MIDDLE SMITHIAN (EARLY TRIASSIC) AMMONOIDS OF GORNJI BRČELI (SOUTHERN MONTENEGRO)

A rich Early Triassic (Smithian) ammonoid fauna discovered near the village of Gornji Brčeli (southern Montenegro) is unique for the Early Triassic of the western Tethys. The Smithian there is represented by a series of several tens of meters thick brown-red to grey-green marls and clays with intercalated, mica-rich, thin dark grey sandstones, and subordinate occurence of redeposited oolitic limestone. The fossils have been collected as scree material over a few square meters but are considered as contemporaneous since no unnatural association (condensation) was detected. The ammonoid assemblage is represented by 15 species, belonging to the genera Aspenites, Cordillerites, Dieneroceras, Abrekites, Owenites, Pseudaspenites, Pseudosageceras, Truempyceras, Wyomingites, Hanielites, Galfettites, Parahedenstroemia, Lingyunites and Pseudoflemingites, and can, by the presence of Owenites zitteli Smith, be correlated with the late Middle Smithian Nyamalites angustecostatus beds of the southern Tethys, the upper Owenites koeneni beds of South China or the Owenites beds of North America. Taxonomic composition of the ammonoid assemblage shows great similiarity with those of Spiti (India), NW Guangxi (China) and Nevada (USA), but also some with those of Salt Range (Pakistan) and Timor. A markedly dominance of involute, oxycone and platycone morphologies distinguishes the Gornji Brčeli fauna from other contemporaneous faunas and points to specific palaeoecological environmental conditions. Previously, three new species were described from this locality and in the present paper one more is added (Parahedenstroemia? tatjanae). Two species hitherto considered as synonyms (Abrekites arthaberi and Owenites zitteli) are revised and treated as valid based on new material from Gornji Brčeli.

Middle Eocene benthic foraminifera from Qattamiya area, Cairo\u2013Suez district, Egypt: biostratigraphy, paleoecology, and their relation to the Southern and Western Tethyan Provinces

This study deals mainly with the biostratigraphy, paleoecology and paleobiogeogrphy of the Middle Eocene benthic foraminifera from an outcrop exposed at Qattamiya area, Cairo–Suez district, Egypt. This district is covered by relatively thick Eocene sequences composed of limestone intercalated with shales and marl. Stratigraphically, the oldest rock unit exposed in the study area is the Observatory Formation which is followed by the Qurn Formation. The examination of the collected samples led to the recognition of 27 species belonging to 17 genera and 10 families. Three benthic foraminiferal biozones are recognized Elphidium trompi-Quinqueloculina carinata Assemblage Zone, Bulimina jacksonensis Zone, and Quinqueloculina ludwigi Zone. These local biozones are correlated with their equivalents inside Egypt. Therefore, the age is assigned to the Middle Eocene. To detect the paleoecology of the recorded foraminiferal community, some parameters (Foraminiferal abundance, richness, and the percentages of epifaunal and infaunal species) are calculated. Three local paleoecologic ecozones are proposed signifying a hyper-to hyposaline inner neritic environment for the lower part of the Observatory, the middle shelf with low oxygen conditions for the upper part of the Observatory Formation, and hypersaline inner neritic environment for the Qurn Formation. Recently, multivariate analyses are considered as a valuable tool in establishing the paleoecology and paleobiogeographical provinces of the Paleogene microfossils. In this study, a matrix composed of 18 species from six countries (Tunisia, Egypt, Libya, France, Spain and Italy) is suggested for multivariate analyses. This matrix is subjected to the principal component analysis (PCA) and the Q-mode cluster analysis to detect the possible provinces. Consequently, two significant provinces are detected, the Southern Tethyan Province (Tunisia, Libya and Egypt) and the Western Tethyan Province (Spain, Italy, and France). Based on the similarity index, there is a strong similarity between the two provinces, which proposes a marine connection between them during Eocene.

An integrated workflow for petrophysical characterization, microfacies analysis, and diagenetic attributes of the Lower Jurassic type section in northeastern Africa margin: Implications for subsurface gas prospection

The Jurassic sedimentary sequences are an important source and reservoir rocks in the North Africa margin, with its type section, outcropped at the Gebel El-Maghara massif and some other sites along the southern Tethys. These exposed Jurassic outcrops, of the intercalated continental and marine sediments, allow us to conduct more detailed and integrated studies on the various depositional settings with diverse lithologies as analogous for the subsurface reservoirs. The present study concerns the implication of the mineralogical components and the diagenetic controls on the petrophysical properties and the reservoir characteristics of the Lower Jurassic in Gebel El-Maghara outcrop sequence (from base to top Mashaba, Rajabia, and Shusha Formations) in north Sinai, Egypt. Some field trips were conducted, and samples were collected, to characterize the petrographical and petrophysical characteristics of these deposits using comprehensive standard techniques including studying thin sections, SEM imaging, XRD analysis, and various petrophysical measurements. A workflow is proposed to apply a full set of petrophysical measurements on the collected samples including porosity (∅He), permeability (k), grain and bulk densities (ρg and ρb, respectively), and true formation resistivity factor. In this workflow, we have integrated the petrophysical data with detailed microfacies analysis to reveal the implication of diagenesis on the reservoir quality of the Lower Jurassic reservoirs. The Lower Jurassic sequence is subdivided into five hydraulic flow units (HFUs) that consist of three reservoir rock types (RRTs). These RRTs are composed of three microfacies associations (MFAs). The RRT1 plug samples consist of the mostly clastic MFA1; they are porous, permeable, and have good reservoir quality that is using the flow zone indicator (FZI), and the reservoir quality index (RQI). The lowest reservoir quality is assigned to the RRT samples which are mostly composed of tight carbonates. Based on the petrographical studies, SEM imaging, and the XRD analysis, dissolution and fracturing slightly enhanced the reservoir potentiality of the RRT1 samples, whereas physical compaction, tight cementation, and authigenic clay content (kaolinite, hematite, and goethite) are responsible for the deterioration of the reservoir properties of RRT3 samples and reduction of the RRT2 samples. The study outcrop has the potential to be an excellent analogue for the important subsurface Jurassic gas-bearing deposits on the African's northern margins. Furthermore, it may provide insights into the fluid flow units, mineralogical composition, and diagenetic controls on the unique Lower Jurassic deposits of Gebel El-Maghara for the assessment of subsurface gas-bearing sequences in the nearby Mediterranean and Gulf of Suez from the southern Tethys shorelines.

Paleoenvironment, sequence stratigraphy and source rock potentiality of the Cenomanian-Turonian boundary sediments of Southern Tethys

The Abu Qada Formation is a reference interval for the Cenomanian–Turonian boundary event in the northeastern margin of Africa. In this paper, geochemical, biostratigraphical, and carbon isotope ratio studies are presented using high-resolution well data yielded from the Gulf of Suez, Egypt to evaluate the paleoenvironmental condition, sequence stratigraphy and source rock potential of the Upper Cenomanian/Lower Turonian Abu Qada Formation. A total of 12 core samples and 4 ditch cuttings were collected from OCT-A8St1 well in the October Oil Field for geochemical, palynological and calcareous nannoplankton analyses. Cyclostratigraphic analysis was prepared to characterize the electrofacies change along the Cenomanian/Turonian boundary interval including the Oceanic Anoxic Event 2 (OAE2). The Predictive Error Filter Analysis (PEFA) patterns and Integrated Predictive Error Filter Analysis (INPEFA) curves found 3rd order cycle of the OAE2 within the global third-order cycle Ce5. A stable carbonate isotope analyses with total organic carbon (TOC) resulted in a remarkable positive excursion δ13Ccarb (3.67‰) associated with change in the TOC content. The quantitative analysis of calcareous nannofossils indicates the high productiveness of nannoplankton around the Cenomanian/Turonian boundary interval. The high abundance of the Discorhabdus genus proves the paleoenvironmental change during the OAE2 interval. The palynofacies interpretation indicates the lower part of Abu Qada Formation to be deposited in a slightly reducing conditions at the inner neritic setting, while the upper part of Abu Qada to lower part of Wata formations were deposited in deeper marine setting under anoxic conditions. These changes in the overall depositional conditions are documented by the remarkable change in palynofacies and organic carbon content (TOC). Dark gray shale and carbonate sediments are interpreted to be a good source rock potential by kerogen quantified palynofacies analysis indicating oil and gas prone producing materials (Kerogen types II and II/III). The best source rock quality is associated with the Abu Qada Formation's OAE2 record. These criteria allow us to identify the occurrence of OAE2 record in the Gulf of Suez petroleum province as a useful tool for high-resolution chronostratigraphic analysis.

STRATIGRAPHY, TAXONOMICAL CONSIDERATION AND EVOLUTIONARY TRENDS OF FUTYAN BENTHIC FORAMINIFERAL JORDANIAN SPECIES

Two hundred and twenty-seven Maastrichtian-Early Paleogene benthic foraminiferal species were recorded from three widely separated surface Jordanian sections: Wadi Arab in the north, Muwaqqar in the center, and Tell Burma in the south. Forty-two species and subspecies were listed. Fifteen diagnostic species of them are treated by him as new species, which recorded and illustrated in this study. The paleogeographic distribution of them in some other countries in the Southern Tethys are recorded: United Arab Emirates (UAE), Egypt, Tunisia, Tanzania and Angola. One of the original species of Futyan: Siphogenerinoides elnaggari is considered here as a junior synonym of another species Orthokarstenia higazyi (Nakkady). The paratype of the recorded species Vaginulinopsis wadiarabensis Futyan is considered recently, by the present author, as a new genus and species: Lenticuzonaria hodae, while the holotype of it was regarded to be the holotype of the new genus Percultalina. As a token of appreciation of his outstanding career and faunal contributions, one species was recently erected: Pseudoclavulina futyani. Most of the recorded species (10 species) are endemic to Jordan, while others were recorded in other countries in the Southern Tethys. Most of these species are used to introduce an evolutionary trend marked by changes in the morphology and other characters of these benthic foraminiferal test. The Jordanian assemblage indicates an open marine environment, which represents middle-outer neritic environment (100 m ~ 200 m depth) and shows an affinity with Midway-Type Fauna (MTF).