Southern Tethyan Margin Research Articles

Composite Mesozoic Carbon and Oxygen Isotope Signals of Selected Events as Encountered in the Southern Tethyan Margin: an Overview

Composite Mesozoic Carbon and Oxygen Isotope Signals of Selected Events as Encountered in the Southern Tethyan Margin: an Overview

Paleo-redox conditions during the demise of a carbonate platform in the Tethyan ocean: Evidence from phosphatized and metals (Mn and Fe) rich hardgrounds

Phosphatized Mn and Fe rich hardgrounds and condensed pelagic deposits in carbonate platform successions are precious archives of abrupt climate and environmental changes (redox conditions and phosphorous availability) in the past shallow-water marine environment. While numerous examples have been documented in the Cretaceous successions of the Northern Tethys, the scarcity of similar descriptions from the southern margins suggests differences in sedimentary processes or preservation conditions.In this work we study three phosphatized Mn and Fe rich hardgrounds and pelagic condensed deposits that mark the repetitive demise of the Panormide carbonate platform developed in the Southern Tethyan margin during the Cretaceous. The integration of SEM-EDS, PXRD, and Micro-Raman spectroscopy data shows that these hardgrounds consist of fine-grained Fe (goethite and hematite) and Mn (birnessite and/or vernadite) oxides dispersed in a calcite and apatite matrix. Micro-Raman spectroscopy shows the presence of oxidized Mn species: Mn3+ and Mn4+. The oxidation of Mn2+ → Mn3+/4+ and/or Fe2+ → Fe3+ occurred at the sediment-seawater interface under oxic conditions (where both Mn and Fe oxidize) or suboxic conditions (where only Fe oxidizes). The paleoenvironmental perturbations that triggered the formation of both hardgrounds and condensed pelagic deposits were likely related to pCO2 cycle, upwelling of P-Mn-Fe-rich water masses, eutrophication and phosphatization related to the Cretaceous climate oscillations during the main Oceanic Anoxic Events. These perturbations were likely enhanced by tectonic activity. Moreover, we show that the formation of the phosphatized metals-rich hardgrounds and the recovery of shallow-water sedimentation occurred after long-term periods (6–12 Ma). Thus, the Panormide serves as a remarkable example of resilience amidst significant climatic changes.

Multiproxy faunal analysis of the middle – upper Eocene deposits in the Fayum area, Egypt: Insights into sequence stratigraphy, trophic conditions, and oxygenation

The Eocene epoch experienced significant fluctuations in climate, ranging from intense greenhouse warming to icehouse cooling, which profoundly impacted the global depositional systems. The middle – upper Eocene deposits in Garet Gehannam, Fayum area, Egypt, present an exciting opportunity to explore paleoenvironmental dynamics using a multiproxy dataset of calcareous nannofossils, benthic foraminifera, ostracods, and molluscan assemblages. Calcareous nannofossil biostratigraphy constrained the studied sequence to the NP17 and NP-19-20 zones. Furthermore, three 3rd-order depositional sequences, BAR.SQ.1, BAR.SQ.2, and PR.SQ.3 were identified. The BAR.SQ.1 sequence encompasses the Gehannam Formation, with a transgressive systems tract (TST) and a highstand systems tract (HST). The BAR.SQ.2 sequence corresponds to the lower Birket Qarun Formation and exhibits a TST/HST pattern. The PR.SQ.3 sequence, however, consists solely of a TST spanning the upper Birket Qarun and Qasr El Sagha formations. The main trend of our multiproxy-based sea level curve shows an overall stepped Tethyan sea level regression within the 2nd-order cycle. This regression is characterized by a transition from outer neritic to inner settings, interrupted by two minor 3rd-order transgressive pulses. This sea level trend was likely driven by global eustatic changes and regional tectonic uplift related to the final collisional phase between Africa/Arabia and Eurasia, which led to the closure of the Neotethys Ocean. Multiproxy faunal analysis reveals a pronounced upsection shift from low-oxic and mesotrophic conditions to well-ventilated, oligotrophic settings tracking long-term sea level fall. The lowering of the sea level may have expanded aerobic ventilation windows on the continental shelf while potentially reducing nutrient influx. Our multiproxy sequence stratigraphic and paleoenvironmental analysis provides insights into the complex interplay of tectonic, eustatic, and climatic influences on the region during the middle – late Eocene episode along the southern Tethyan margin.

Jurassic and Cretaceous crinoids (Crinoidea, Echinodermata) from the southern Tethys margin (northern and eastern Africa, and southern Asia)

Jurassic and Cretaceous crinoids (Crinoidea, Echinodermata) from the southern Tethys margin (northern and eastern Africa, and southern Asia)

Taxonomic review, palaeoecological, and palaeobiogeographical significances of Campanian Tethyan oysters from the North Eastern Desert, Egypt

The Late Cretaceous was a time of high eustatic sea level that enabled extensive epicontinental seaways and carbonate platforms across the Tethyan Realm, providing favorable habitats for oyster communities to flourish. This study focuses on the Campanian Tethyan oysters from the North Eastern Desert of Egypt regarding taxonomy, palaeoecology, and palaeobiogeography. Three oyster species, Nicaisolopha nicaisei (Coquand, 1862), Pycnodonte (Phygraea) vesicularis (Lamarck, 1806), and Ambigostrea bretoni (Thomas and Peron, 1891), were identified from the Campanian succession in two studied sections. The sampled specimens of the genus Nicaisolopha have undergone a systematic palaeontological revision. As a result, N. tissoti (Thomas and Peron, 1891) is considered herein a junior synonym of N. nicaisei (Coquand, 1862). Palaeobiogeographically, the likely primary migration pattern of the studied oysters suggests an east–west trend along the Southern Tethys margin. All identified oysters in this study exhibit a Tethyan affinity and are primarily abundant in two main provinces: the Southern Tethys and the Western Tethys. The macrofaunal contents are categorized into two fossil associations: the Nicaisolopha nicaisei association of the middle-late Campanian age and the Pycnodonte vesicularis association of the late Campanian age. These macrofaunal associations indicate a deepening trend during the middle-late Campanian age, suggesting a transition from shallow inner neritic to middle neritic environments. Additionally, it is observed that Pycnodonteinae tend to grow larger under eutrophic conditions, low-energy environments, and nutrient-rich waters with high carbonate contents.

Note on the earliest records of genus Macrocephalites Zittel: implications for biostratigraphic correlations

ABSTRACT The Bathonian‒Callovian (Middle Jurassic) genus Macrocephalites Zittel is distributed worldwide, and several of its species are used for inter- and intrabasinal biostratigraphic correlations. Here, the earliest occurrence of genus Macrocephalites, using an integrated approach incorporating data from ammonites, calcareous nannofossils and magnetostratigraphy from the Kachchh Basin of western India is presented. The calcareous nannofossils were extracted from the Macrocephalites triangularis Spath (m) sample, and the magnetostratigraphic data also comes from the same ammonite-bearing bed (Yellow Bed, bed A4), in the core of the Jumara Dome, Kachchh Basin. The sample yielded age-diagnostic calcareous nannofossil taxa with FOs (First Occurrence) of Pseudoconus enigma, Cyclagelosphaera margerelii, Octopodorhabdus decussatus and Watznaueria barnesiae, and the LO (Last Occurrence) of Carinolithus magharensis, thus, bracketing the age of the Yellow Bed between early to early middle Bathonian. An early middle Bathonian age was also proposed previously based on an ammonite assemblage and correlated with the Standard European early middle Bathonian Progracilis Zone. The magnetostratigraphic data yielded an early Bathonian age, but, it is of very low resolution, and possibly re-magnetised. The occurrence of M. aff. triangularis Spath from eastern Crimea from below the Bremeri Zone (middle Bathonian), corroborating the early middle Bathonian age arrived at for the earliest occurrence of M. triangularis in the Kachchh Basin, is also evaluated. The stratigraphic occurrence of a heavily encrusted M. triangularis specimen from Germany, and assigned to the lower Callovian, is also evaluated. The present data suggests that genus Macrocephalites Zittel was already well-established even in the early middle Bathonian, if not earlier, and that a relook/resampling is urgently needed with an integrated approach for southern Tethyan margin localities such as Madagascar and Sula Island.

Response of the calcareous nannofossils to the Cretaceous-Paleogene boundary event: A case study from Sinai, Egypt

A detailed study of calcareous nannofossils was conducted on a well-exposed succession encompassing the Cretaceous-Paleogene (K-Pg) boundary interval at Wadi Nukhul, Sinai, Egypt, as a part of the southern Tethyan margin. The nannofossil biostratigraphic data show that the Nukhul succession sustains a complete K-Pg boundary interval. The nannofossil assemblage indicates a shift from cool/oligo-mesotrophic conditions in the late Maastrichtian Micula murus Zone to warm/oligotrophic in the latest Maastrichtian M. prinsii Zone prior to the K-Pg boundary. At the K-Pg boundary, diversity, and total abundance of the calcareous nannofossils remarkably decreased signifying unstable marine conditions. The post-impact assemblage (lowermost part of NP1 Zone) was marked by acme of Cervisiella operculata indicating oligotrophic conditions in the photic zone related to the diminished of the marine primary producers in the lowermost Danian. At the upper portion of the NP1 Zone, the assemblage is still dominated by C. operculata, besides the successive occurrence of the small-sized incoming Paleocene taxa Biantholithus sparsus and Neobiscutum romeinii. This pattern was accompanied by increased frequencies of Zeugrhabdotus sigmoides indicating stressful cool/meso-eutrophic surface water conditions signify the initial recovery interval. Upward in the early Danian NP2-NP3 zones, the nannofossil species diversity and total abundance progressively increased. Also, the nannofossil assemblage characterized by the existence of the new Paleocene oligotrophic indicators like Cruciplacolithus primus, Coccolithus pelagicus, and Ericsonia subpertusa. This probably indicates a tendency toward rebuilding of the biological pump efficiency and, therefore, a full recovery phase was resumed.

Integrated biostratigraphy and chemostratigraphy of the Maastrichtian–Danian succession at Abu Minqar, Egyptian Western Desert: Implications for sequence stratigraphy and tectonic influence

We investigated the Maastrichtian–Danian succession at the Abu Minqar section in the Western Desert of Egypt (part from the southern Tethyan margin) using an integrated analysis of biostratigraphic (calcareous nannofossils, foraminifers, macrofauna) and chemostratigraphic data to determine the controlling factors on depositional history. The integrated microplankton biostratigraphic framework identified two prolonged hiatuses at the lower/upper Maastrichtian and the Maastrichtian/Danian boundaries. Four depositional sequences were identified and subdivided into systems tracts based on paleodepth variation evidenced by foraminiferal investigations and the comparable response of the various geochemical indices. The study also highlighted the presence of two alternated depositional styles in the study area, influenced by relative sea level, with the first style involving the deposition of aluminosilicate-enriched intervals that yield non-calcareous foraminifers in lagoonal and coastal depositional settings induced by relative sea-level fall and river rejuvenation, and the second one involving the deposition of calcareous intervals containing abundant megafossils, calcareous foraminifers, and nannofossils during a sea-level rise. Despite the occurrence of certain resemblances to the global eustatic curves, the inferred relative sea level pattern suggests that regional tectonics had a substantial role in developing the depositional history and paleoenvironmental circumstances of the southern Tethys margin. These findings help build a more comprehensive picture of the geological evolution of the southern Tethyan margin during the Late Cretaceous to Paleogene.

Upper Cenomanian caprinulid-radiolitid rudists (Bivalvia) from the Gattar Member of Jebel el Kebar (central Tunisia): Stratigraphical implications and palaeobiogeographical relationships with coeval rudist-assemblages from carbonate platforms of the southern Tethyan margin

The Gattar Member (upper part of the Zebbag Formation) is a prominent dolomitic limestone unit in Tunisia, the age of which was ascribed either to the Turonian, the Cenomanian, or the Cenomanian−Turonian. Here, we present the discovery of a Caprinulidae-Radiolitidae rudist asssemblage in the Gattar Member of Jebel el Kebar (central Tunisia). This consists of Caprinula cf. boissyi, Sauvagesia cf. sharpei, Durania arnaudi, Neocaprina sp. and Eoradiolites sp. The detailed description of two sections of the Gattar Member in Jebel el Kebar allows us to define the sedimentological and palaeoecological attributes of the rudist-bearing carbonates and their sequential relationships with the Zebbag and Rouana stratigraphical units respectively. The caprinulid-radiolitid assemblage is age-calibrated, based on the ammonite standard zonation of the Cenomanian stage from Portugal, South-Eastern France, and Oman, where rudist, benthic foraminifera and ammonite Zones have been correlated. Its age is late Cenomanian. The correlations of the Gattar Member between central Tunisia and the Gafsa-Chotts area are established on the base of ammonite and rudist biostratigraphical markers. The age of the Gattar Member of southern Tunisia and of its stratigraphical counterpart in western Libya is discussed. At last, we analyze the palaeobiogeographical distribution of the upper Cenomanian caprinulid-radiolitid assemblages from coeval carbonate platforms of the North African margin (Algeria, Morocco) and of the North Arabian margin (Levant region: Syria, Jordan, Lebanon, Israel, North Sinai).

A new Palaeogene elasmobranch fauna (Tebessa region, eastern Algeria) and the importance of Algerian-Tunisian phosphates for the North African fossil record

During the Palaeocene-Eocene transition, the southern Tethys margin is characterized by several African phosphate deposits with many fossil teeth of elasmobranchs. Contrary to the rich Moroccan fossil record, fossil elasmobranchs from the area that includes today the Algerian-Tunisian border (e.g. Metlaoui-Gafsa-Onk Basin) have received few attentation since the last century of exploration. New collecting in the vicinity of Tebessa, Eastern Algeria (Jebel El Onk mine) allowed to report a new elasmobranch fauna in the so-called “Upper Thanetian” level. It consists of 28 taxa including a new species of a galeocerdid, Physogaleus onkensis sp. nov., which is characterized by a possible crushing adaptability of their teeth. The majority of the reported species are known in coeval phosphate levels enabling preliminary conclusions about the depositional time and correlations to the related faunas of the region. The faunal from the Jebel El Onk mine is considered as late Thanetian–early Ypresian in age.

The Albian – Cenomanian boundary on the southern Tethyan margin: Abu Gharadig Basin, Northern Western Desert, Egypt

Lithostratigraphy and biostratigraphy sometimes provide contradictory interpretations, especially when trying to establish a chrono-lithological boundary between two reservoir formations from different paleoenvironments. One of these contradictions is the definition of the boundary between the Kharita and Bahariya formations and the Albian and Cenomanian Stages in the Abu Gharadig Basin of the Western Desert, Egypt. an integrated approach has been applied to this problem using borehole image logs, palynology, and conventional wireline logs. authors also calibrate the stratigraphic sections with global chronostratigraphic charts, using nannoplankton, planktonic foraminifera, and dinoflagellates to construct a better understanding of this basin. The abundances of pollen, spores, and dinoflagellates in the interpreted reservoir intervals suggest that hydrocarbons trapped in the Albian-Cenomanian reservoirs are composed of type II/III kerogen. The interpreted intervals are subdivided into seven depositional cycles: one in the Kharita Formation, five in the Bahariya Formation, and one in the Abu Roash Formation. The interpreted environments are, from bottom to top: I) fluvio-deltaic distributary channels, II) and III) intertidal to subtidal deposits, IV) offshore bar deposits, V) intertidal to subtidal deposits, VI) shoreface deposits, and VII) shallow marine carbonate deposits. Diagnostic palynomorphs reflect climatic change from arid to humid conditions and also enable changes in salinity to be determined.Much of the published work in the southern Tethyan margin, particularly in the Western Desert, is either related to stratigraphy, palynology, or reservoir evaluation with a focus on a narrow field. Tectonostratigraphic studies and analyses of petroleum system elements have often been very regional in nature. The work presented here is of an intermediate scale linking regional frameworks with local details to provide comprehensive information about the Albian-Cenomanian succession in the Northern Western Desert. The focus has been the Abu Gharadig basin but this integrated approach has implications for other basins in North Africa. A specific example is the similarity of Western Desert and Libyan Sirt basin Albian-Cenomanian key palynomorphs which would facilitate a similar integrated chrono-lithologic intepretation.

The unexpected occurrence of enigmatic ‘percevalicrinids’ (Echinodermata, Crinoidea) in the Lower Jurassic strata of North Africa — Implications for their stratigraphic and palaeogeographic distribution and discussion on their belonging to the subfamily Balanocrininae

The marl and limestone alternations of the Lower Jurassic Ain Ouarka and Ain Rhezala formations (Pliensbachian–Toarcian) in the western Saharan Atlas, Northwest Algeria, yield a diverse micro- and macrofauna, including moderately numerous crinoids, which are represented by remains of isocrinids, i.e., Balanocrinus ticinensis Hess and columnals of the genus Percevalicrinus. So far, the latter genus has been observed from the Upper Jurassic–Lower Cretaceous strata of Eurasia, North America, and the African continent. Thus, the present find is the oldest record of this crinoid genus, and the second one from the southern Tethyan margin. In this paper, it is shown that Percevalicrinus, which is traditionally regarded as a representative of the subfamily Balanocrininae, displays several features of the subfamily Isocrininae. The crinoid assemblage and associated facies and invertebrate fauna are typical of a low-energy deep outer shelf/ramp (below the storm wave-base) setting.

Paleoenvironment, sequence stratigraphy, and sea level change in the upper Maastrichtian–Danian boundary interval in Gabal Aras, east Qena, Nile Valley, Egypt

The Cretaceous–Paleogene (K–Pg) boundary interval at Gabal Aras, Qena region (part of the southern Tethyan margin) was investigated in detail for calcareous nannofossil and foraminiferal (planktonic and benthonic) assemblages to characterize the surface and bottom sea water conditions. The K–Pg boundary is marked by a minor hiatus expressed by the absence of the lowermost Danian P0 and Pα planktonic foraminiferal zones. Benthonic foraminifera assemblages indicate moderately oxygenated bottom sea waters associated with oligo-mesotrophic conditions during early late Maastrichtian, and mesotrophic conditions during the latest Maastrichtian. The benthonic foraminiferal assemblage reflects a decrease in the food supply in the bottom sea water during the early Danian, while well-oxygenated and oligotrophic conditions dominated during late Danian. The late Maastrichtian surface water witnessed a general cooling trend that was interrupted by a warming episode that could correspond to the Late Maastrichtian Warming Event (LMWE). Acme of Thoracosphaera associated with increased abundance of Neobiscutum romeinii were observed within the upper part of NP1 Zone indicating stressful surface water conditions. The increase of the epifaunal foraminiferal taxa and the occurrence of Cruciplacolithus primus throughout NP2 and NP3 zones reflect a progressive return to normal marine conditions. In the framework of sequence stratigraphy, two third-order depositional sequences covering the K–Pg boundary interval were identified, interpreted, and correlated. The obtained sea-level curve was evaluated to assess whether it was controlled by the eustatic sea-level changes, regional tectonics, or both these factors.

Sedimentology and New Paleogeographic Data of the Lower Eocene Chouabine Formation in the Gafsa Basin (Tunisia), Southern Tethyan Margin

Abstract Facies and paleo-environment reconstruction applied to the lower Eocene Chouabine deposits occurring in the Gafsa area in Tunisia provided important information on sediment cyclicity and paleogeographic conditions. From west to east, four sections were surveyed: Tamerza (25 m), Oued Thelja (48 m), Jebel Ong (25 m), and Jebel Chamsi (45 m). Furthermore, the facies stacking pattern allowed for the reconstruction of depositional environments in relation to sea level changes. The Chouabine Formation is formed by the succession of three sequences composed of marls, phosphorites, and carbonates. There are five main facies organized into two transgressive cycles. The gradual transition of facies from intertidal to circatidal environments unraveled the sedimentation on a homoclinal ramp, episodically swept by upwelling currents. The Chouabine Formation is made of deepening–upwards cycles. Each cycle ranges from 2 to 5 m in thickness. The proximal-distal transition of depositional environments was gradually increasing from intertidal to offshore environments. Lateral variation of thickness and facies is generated by the reactivation of inherited NW-SE extensive and/or transtensive faults, acting since the late Cretaceous during the intermediate closing phase of the Neotethys. Synsedimentary tectonics has created trap structures favouring confinement conditions in the center of the basin, permitting the accumulation and preservation of large thicknesses of phosphate deposits. Based on new litho- and biostratigraphic data, this study presents for the first time a clear and detailed regional stratigraphic correlation and paleogeographic maps.

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.

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.

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

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.