“…However, Li and Keller (1998b) reported the presence of A. mayaroensis within the C31r chron in DSDP Hole 525A located in the South Atlantic. Therefore, the LO of A. mayaroensis is not a reliable biostratigraphic marker due to its latitudinal diachronism and scarcity, or absence in shallow‐water environments and tropical regions (Bazeen et al, 2021; Coccioni & Premoli‐Silva, 2015; Li et al, 1999; Pérez‐rodríguez et al, 2012).…”
Section: Discussionmentioning
confidence: 99%
“…However, such studies are also beset with major palaeobiologic, palaeoclimatic and palaeoceanographic inconsistencies (Farouk et al, 2021). Several palaeo-latitudinal-driven discrepancies have been documented, leading to major differences in the stratigraphic ranges of planktic foraminiferal bioevents, such as the endemism of marker taxa, diachronism, absence of index species due to preservational issues, and the use of varied biostratigraphic and taxonomic approaches (Bazeen et al, 2021;Coccioni & Premoli-Silva, 2015;Farouk, 2014;Gardin et al, 2012;Hewaidy et al, 2019;Huber et al, 2008;Li & Keller, 1998a;Pérez-rodríguez et al, 2012;Robaszynski & Caron, 1995;Voigt et al, 2012;Wendler, 2013). Hence, a detailed analysis of species distribution patterns coupled with isotope studies from a complete section would enable to infer changes in the palaeoenvironment and that, in turn, will provide a window for better understanding the aforementioned discrepancies.…”
Based on quantitative changes in the Maastrichtian planktic foraminiferal species distribution patterns from the Elles section (central Tunisia), δ13C, δ18O‐based palaeotemperature and inferred proxies (species diversity, ecological associations, and depth ranking), the palaeoenvironment is inferred. Based on Constrained Clustering and corroborated by Non‐metric Multidimensional Scaling (NMDS), four statistically significant intervals are identified. Interval 1 (lower–middle part of CF5 Zone) is marked by a warm, oligotrophic, stable, and well‐stratified upper water column. Interval 2 (upper part of CF5 Zone), here designated as the pre‐Mid‐Maastrichtian Event (MME) event, is marked by stressed, warmer, moderately mesotrophic, and weakly stratified surface waters with an unstable upper water column. Interval 3 (CF4 Zone) encompasses the MME and is marked by warm, stable, mesotrophic surface waters with a moderately well‐stratified upper water column. The upper part of Interval 3, designated as post‐MME, is also marked by mesotrophic conditions, but with increased surface water warming, unstable and stressed conditions. Interval 4 (CF3–CF1 zones) shows the effects of the Indian Deccan volcanism, and is marked by warmer surface waters, mesotrophic, unstable, stressed environmental conditions, with a weakly‐stratified upper water column.
“…However, Li and Keller (1998b) reported the presence of A. mayaroensis within the C31r chron in DSDP Hole 525A located in the South Atlantic. Therefore, the LO of A. mayaroensis is not a reliable biostratigraphic marker due to its latitudinal diachronism and scarcity, or absence in shallow‐water environments and tropical regions (Bazeen et al, 2021; Coccioni & Premoli‐Silva, 2015; Li et al, 1999; Pérez‐rodríguez et al, 2012).…”
Section: Discussionmentioning
confidence: 99%
“…However, such studies are also beset with major palaeobiologic, palaeoclimatic and palaeoceanographic inconsistencies (Farouk et al, 2021). Several palaeo-latitudinal-driven discrepancies have been documented, leading to major differences in the stratigraphic ranges of planktic foraminiferal bioevents, such as the endemism of marker taxa, diachronism, absence of index species due to preservational issues, and the use of varied biostratigraphic and taxonomic approaches (Bazeen et al, 2021;Coccioni & Premoli-Silva, 2015;Farouk, 2014;Gardin et al, 2012;Hewaidy et al, 2019;Huber et al, 2008;Li & Keller, 1998a;Pérez-rodríguez et al, 2012;Robaszynski & Caron, 1995;Voigt et al, 2012;Wendler, 2013). Hence, a detailed analysis of species distribution patterns coupled with isotope studies from a complete section would enable to infer changes in the palaeoenvironment and that, in turn, will provide a window for better understanding the aforementioned discrepancies.…”
Based on quantitative changes in the Maastrichtian planktic foraminiferal species distribution patterns from the Elles section (central Tunisia), δ13C, δ18O‐based palaeotemperature and inferred proxies (species diversity, ecological associations, and depth ranking), the palaeoenvironment is inferred. Based on Constrained Clustering and corroborated by Non‐metric Multidimensional Scaling (NMDS), four statistically significant intervals are identified. Interval 1 (lower–middle part of CF5 Zone) is marked by a warm, oligotrophic, stable, and well‐stratified upper water column. Interval 2 (upper part of CF5 Zone), here designated as the pre‐Mid‐Maastrichtian Event (MME) event, is marked by stressed, warmer, moderately mesotrophic, and weakly stratified surface waters with an unstable upper water column. Interval 3 (CF4 Zone) encompasses the MME and is marked by warm, stable, mesotrophic surface waters with a moderately well‐stratified upper water column. The upper part of Interval 3, designated as post‐MME, is also marked by mesotrophic conditions, but with increased surface water warming, unstable and stressed conditions. Interval 4 (CF3–CF1 zones) shows the effects of the Indian Deccan volcanism, and is marked by warmer surface waters, mesotrophic, unstable, stressed environmental conditions, with a weakly‐stratified upper water column.
“…Thus, the MFS separates the TST from the HST and accounts for the greater water depth of the sequence. We distinguished the MFS as peaks in the abundance of planktonic foraminifera, calcareous nannofossil, and the infaunal benthic taxa such as Uvigerina and Bulimina (Bazeen et al, 2021; Leckie & Olson, 2003; Loutit et al, 1988).…”
The calcareous nannofossil and foraminiferal analyses have been integrated to build a detailed chronostratigraphic scheme for the upper Oligocene-middle Miocene succession in the Nukhul-Sudr area, west-central Sinai, Egypt. The palaeoenvironmental conditions of the studied succession were assessed using the palaeoecologic preferences of calcareous nannofossil species, benthic foraminifera, and planktonic/benthic (P/B) ratios. Six complete and two incomplete depositional sequences bounded by seven sequence boundaries have been distinguished in the studied sections based on the integration between chronostratigraphic and palaeoenvironmental interpretations as well as the nature of stratigraphic surfaces. Levels suggesting subaerial exposures (such as alluvial fans and polymictic conglomerates) and biostratigraphic breaks were employed to delineate sequence boundaries. The inferred relative sea-level curve points to palaeodepth change ranging from lagoonal to outer shelf settings during the deposition. The established upper Oligocene-middle Miocene sequence stratigraphic framework demonstrates a more-or-less compatible correlation toward the corresponding ones from the neighbouring localities around the eastern rim of the Gulf of Suez. However, the inferred relative sea-level curve shows significant deviations when compared with the eustasy. These deviations are expressed mainly by several prolonged time gaps and discrepancies in the timing and magnitude of the transgression and regression events. Therefore, the Gulf of Suez rift Basin development and the coincident regional tectonic events are the main controlling factors for the sedimentation regime in west-central Sinai.
“…This area was located along the Southern Tethys Ocean's passive continental margin during the Late Cretaceous. Over time, the shallow epicontinental sea in this region gradually became deeper as it moved northward, eventually forming the Neo-Tethys Ocean basin 10 – 13 . The Syrian Arc Fold Belt developed along the northern passive margin of the African-Arabian plate due to the convergence of Africa and Eurasia, starting in the Turonian 14 .…”
Section: Geologic Setting and Lithostratigraphymentioning
confidence: 99%
“…2 ). Figure 1 Geological map of the North Eastern Desert with the location of the studied sections (reprinted after Bazeen et al 10 with permission from Elsevier). This geological map was modified from the geological map of Egypt, Beni Suef sheet- NH36SW (after Klitszch et al 18 ).…”
Section: Geologic Setting and Lithostratigraphymentioning
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.
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