Abdel Aziz Tantawy | Aswan University (original) (raw)
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ABSTRACT Five Late Cretaceous-Early Tertiary successions outcropping along the western scarp whic... more ABSTRACT Five Late Cretaceous-Early Tertiary successions outcropping along the western scarp which faces the Nile Valley between Sin El Kaddab in the south and Wadi Abu Ghurra in the north, Western Desert, have been critically investigated both lithologically and micropaleontologically. This enabled a correlation with comparable K-T successions in Egypt. The succession is subdivided into a number of lithologic and biostratigraphic units, and the foraminifera are used to interprete the stratigraphy and paleoecology of the region. Biostratigraphic interpretation reveals that the Campanian/Maastrichtian boundary cuts through the lower part of Kiseiba Formation which represents the southern nearshore facies of Qusier Formation and the greater part of Dakhla Formation. The Maastrichtian/Danian boundary lies in the north within the upper third part of the Dakhla Formation, whereas in the south it is coincident with the lithologic boundary between Kiseiba and Kurkur formations. A distinct ...
Palaeogeography, Palaeoclimatology, Palaeoecology, 2015
ABSTRACT The Paleocene-Eocene Thermal Maximum (PETM) shows an extraordinary drop in the δ13C of c... more ABSTRACT The Paleocene-Eocene Thermal Maximum (PETM) shows an extraordinary drop in the δ13C of carbonate and organic matter across the globe, suggesting massive release of 13C-depleted carbon dioxide into the ocean and atmosphere over a very short time interval (probably b20ky). We report a geochemical and mineralogical study of 106 samples spanning the most expanded PETM at the Dababiya Global Stratotype Standard section and Point (GSSP) near Luxor, Egypt. The field and laboratory observations reveal that the deposition occurred in a submarine channel extended laterally about 200 m with the deepest part (~0.88 m) at the designated GSSP, although all bio-zones are present. Stable isotope records of both carbonate and organic carbon show decreases starting 0.6 m below the Paleocene-Eocene boundary (PEB) and culminating at the erosion surface. A persistent shift in δ15Norg values to near zero reflects a gradual increase in bacterial activity. High Ti, K and Zr and low Si contents at the PEB coincide with increased kaolinite contents, which suggests intense chemical weathering under more humid conditions at the PETM onset. Two negative Ce-anomalies indicate intervals of anoxic conditions during the lower and middle PETM (base and top of zone E1). The first anoxic event is represented by a negative Ce-anomaly, high V/C rand V/V+Ni ratios, negative Mn* and an abundance of idiomorphic pyrite crystals that indicate anoxic to euxinic conditions. The anoxic event (middle PETM) is marked by high U, Mo, V, Fe and abundant small sized (2–5 μm) pyrite framboids, increased Cu, Ni, and Cd at the samelevel suggesting anoxic conditions linked to high surface water productivity. Above this interval, oxic conditions returned as indicated by the precipitation of phosphorus and barium. These data reveal an expanded PETM interval marked by intense weathering as a crucial parameter during the recovery phase.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2013
Palaeogeography, Palaeoclimatology, Palaeoecology, 2009
Eclogae Geologicae Helvetiae
ABSTRACT
The response of shallow-water sequences to oceanic anoxic event 2 and mid- Cenomanian events 1a a... more The response of shallow-water sequences to oceanic anoxic event 2 and mid-
Cenomanian events 1a and 1b was investigated along the west African margin
of Morocco north of Agadir (Azazoul) and correlated with the deep-water
sequence of the Tarfaya Basin (Mohammed Beach) based on biostratigraphy,
mineralogy, phosphorus and stable isotopes. In the deeper Mohammed Beach
section results show double peaks in d13Corg for mid-Cenomanian events 1a
and 1b (Rotalipora reicheli biozone, lower CC10a biozone), the characteristic
oceanic anoxic event 2 d13C excursion (Rotalipora cushmani extinction, top of
CC10a biozone) and laminated (anoxic) black shale. In the shallow
environment north of Agadir, a fluctuating sea-level associated with dysoxic,
brackish and mesotrophic conditions prevailed during the middle to late
Cenomanian, as indicated by oyster biostromes, nannofossils, planktonic and
benthonic foraminiferal assemblages. Anoxic conditions characteristic of
oceanic anoxic event 2 (for example, laminated black shales) did not reach
into shallow-water environments until the maximum transgression of the early
Turonian. Climate conditions decoupled along the western margin of Morocco
between mid-Cenomanian event 1b and the Cenomanian–Turonian boundary,
as also observed in eastern Tethys. North of Agadir alternating humid and dry
seasonal conditions prevailed, whereas in the Tarfaya Basin the climate was
dry and seasonal. This climatic decoupling can be attributed to variations in
the Intertropical Convergence Zone and in the intensity of the north-east trade
winds in tropical areas.
Earth and Planetary Science Letters, 2007
Cretaceous Research, 2007
From the Cretaceous-Tertiary Boundary to the Paleocene-Eocene Thermal Maximum (PETM): New Insight... more From the Cretaceous-Tertiary Boundary to the Paleocene-Eocene Thermal Maximum (PETM): New Insights from the Wadi Nukhul Section (Sinai, Egypt)
![Research paper thumbnail of Corrigendum to: “High stress late Maastrichtian – early Danian palaeoenvironment in the Neuquén Basin, Argentina” [Cretaceous Research 28 (2007) 939–960]](https://attachments.academia-assets.com/39248069/thumbnails/1.jpg)
](Cretaceous Research, 2009
Cretaceous Research, 2001
Cretaceous Research, 2011
Micropaleontology, 2006
ABSTRACT The Paleocene-Eocene transition is exposed at Gebel Serai, 50km east of Qena, and at Tar... more ABSTRACT The Paleocene-Eocene transition is exposed at Gebel Serai, 50km east of Qena, and at Taramsa, 10km west of Qena in the central Nile Valley of Egypt. The continuous deposition across the P/E boundary, the negative delta C-13 excursion (CIE), the good preservation and high diversity of the calcareous nannofossil assemblages as well as the occurrence of distinctive floral events confer to these localities a potential role as P/E reference-sections. A major nannofossil turnover occurs around the P/E boundary (NP9a/NP9b subzonal boundary) marked by an abrupt decrease of Fasciculithus spp. at the onset of CIE concomitant with a sharp decrease in the abundance of Toweius spp.. The middle and upper part of the CIE-interval are characterized by successive shifts of oligotrophic, warm-water taxa, including the first acme of Coccolithus pelagicus/subpertusa, followed by a rapid increase in abundance of Rhomboaster spp., a sharp increase of long-armed, asymmetrical discoasters, and a second shift of Coccolithus pelagicus/subpertusa. Immediately above the CIE-interval and continuing up to the top of the section, a gradual increase of Toweius spp. accompanied by a gradual decrease in Coccolithus pelagicus/subpertusa indicates a return to a cooler, mesotrophic to eutrophic environment.
![Research paper thumbnail of Corrigendum to: “High stress late Maastrichtian – early Danian palaeoenvironment in the Neuquén Basin, Argentina” [Cretaceous Research 28 (2007) 939–960]](https://attachments.academia-assets.com/50257874/thumbnails/1.jpg)
](Cretaceous Research, 2009
ABSTRACT Five Late Cretaceous-Early Tertiary successions outcropping along the western scarp whic... more ABSTRACT Five Late Cretaceous-Early Tertiary successions outcropping along the western scarp which faces the Nile Valley between Sin El Kaddab in the south and Wadi Abu Ghurra in the north, Western Desert, have been critically investigated both lithologically and micropaleontologically. This enabled a correlation with comparable K-T successions in Egypt. The succession is subdivided into a number of lithologic and biostratigraphic units, and the foraminifera are used to interprete the stratigraphy and paleoecology of the region. Biostratigraphic interpretation reveals that the Campanian/Maastrichtian boundary cuts through the lower part of Kiseiba Formation which represents the southern nearshore facies of Qusier Formation and the greater part of Dakhla Formation. The Maastrichtian/Danian boundary lies in the north within the upper third part of the Dakhla Formation, whereas in the south it is coincident with the lithologic boundary between Kiseiba and Kurkur formations. A distinct ...
Palaeogeography, Palaeoclimatology, Palaeoecology, 2015
ABSTRACT The Paleocene-Eocene Thermal Maximum (PETM) shows an extraordinary drop in the δ13C of c... more ABSTRACT The Paleocene-Eocene Thermal Maximum (PETM) shows an extraordinary drop in the δ13C of carbonate and organic matter across the globe, suggesting massive release of 13C-depleted carbon dioxide into the ocean and atmosphere over a very short time interval (probably b20ky). We report a geochemical and mineralogical study of 106 samples spanning the most expanded PETM at the Dababiya Global Stratotype Standard section and Point (GSSP) near Luxor, Egypt. The field and laboratory observations reveal that the deposition occurred in a submarine channel extended laterally about 200 m with the deepest part (~0.88 m) at the designated GSSP, although all bio-zones are present. Stable isotope records of both carbonate and organic carbon show decreases starting 0.6 m below the Paleocene-Eocene boundary (PEB) and culminating at the erosion surface. A persistent shift in δ15Norg values to near zero reflects a gradual increase in bacterial activity. High Ti, K and Zr and low Si contents at the PEB coincide with increased kaolinite contents, which suggests intense chemical weathering under more humid conditions at the PETM onset. Two negative Ce-anomalies indicate intervals of anoxic conditions during the lower and middle PETM (base and top of zone E1). The first anoxic event is represented by a negative Ce-anomaly, high V/C rand V/V+Ni ratios, negative Mn* and an abundance of idiomorphic pyrite crystals that indicate anoxic to euxinic conditions. The anoxic event (middle PETM) is marked by high U, Mo, V, Fe and abundant small sized (2–5 μm) pyrite framboids, increased Cu, Ni, and Cd at the samelevel suggesting anoxic conditions linked to high surface water productivity. Above this interval, oxic conditions returned as indicated by the precipitation of phosphorus and barium. These data reveal an expanded PETM interval marked by intense weathering as a crucial parameter during the recovery phase.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2013
Palaeogeography, Palaeoclimatology, Palaeoecology, 2009
Eclogae Geologicae Helvetiae
ABSTRACT
The response of shallow-water sequences to oceanic anoxic event 2 and mid- Cenomanian events 1a a... more The response of shallow-water sequences to oceanic anoxic event 2 and mid-
Cenomanian events 1a and 1b was investigated along the west African margin
of Morocco north of Agadir (Azazoul) and correlated with the deep-water
sequence of the Tarfaya Basin (Mohammed Beach) based on biostratigraphy,
mineralogy, phosphorus and stable isotopes. In the deeper Mohammed Beach
section results show double peaks in d13Corg for mid-Cenomanian events 1a
and 1b (Rotalipora reicheli biozone, lower CC10a biozone), the characteristic
oceanic anoxic event 2 d13C excursion (Rotalipora cushmani extinction, top of
CC10a biozone) and laminated (anoxic) black shale. In the shallow
environment north of Agadir, a fluctuating sea-level associated with dysoxic,
brackish and mesotrophic conditions prevailed during the middle to late
Cenomanian, as indicated by oyster biostromes, nannofossils, planktonic and
benthonic foraminiferal assemblages. Anoxic conditions characteristic of
oceanic anoxic event 2 (for example, laminated black shales) did not reach
into shallow-water environments until the maximum transgression of the early
Turonian. Climate conditions decoupled along the western margin of Morocco
between mid-Cenomanian event 1b and the Cenomanian–Turonian boundary,
as also observed in eastern Tethys. North of Agadir alternating humid and dry
seasonal conditions prevailed, whereas in the Tarfaya Basin the climate was
dry and seasonal. This climatic decoupling can be attributed to variations in
the Intertropical Convergence Zone and in the intensity of the north-east trade
winds in tropical areas.
Earth and Planetary Science Letters, 2007
Cretaceous Research, 2007
From the Cretaceous-Tertiary Boundary to the Paleocene-Eocene Thermal Maximum (PETM): New Insight... more From the Cretaceous-Tertiary Boundary to the Paleocene-Eocene Thermal Maximum (PETM): New Insights from the Wadi Nukhul Section (Sinai, Egypt)
Cretaceous Research, 2009
Cretaceous Research, 2001
Cretaceous Research, 2011
Micropaleontology, 2006
ABSTRACT The Paleocene-Eocene transition is exposed at Gebel Serai, 50km east of Qena, and at Tar... more ABSTRACT The Paleocene-Eocene transition is exposed at Gebel Serai, 50km east of Qena, and at Taramsa, 10km west of Qena in the central Nile Valley of Egypt. The continuous deposition across the P/E boundary, the negative delta C-13 excursion (CIE), the good preservation and high diversity of the calcareous nannofossil assemblages as well as the occurrence of distinctive floral events confer to these localities a potential role as P/E reference-sections. A major nannofossil turnover occurs around the P/E boundary (NP9a/NP9b subzonal boundary) marked by an abrupt decrease of Fasciculithus spp. at the onset of CIE concomitant with a sharp decrease in the abundance of Toweius spp.. The middle and upper part of the CIE-interval are characterized by successive shifts of oligotrophic, warm-water taxa, including the first acme of Coccolithus pelagicus/subpertusa, followed by a rapid increase in abundance of Rhomboaster spp., a sharp increase of long-armed, asymmetrical discoasters, and a second shift of Coccolithus pelagicus/subpertusa. Immediately above the CIE-interval and continuing up to the top of the section, a gradual increase of Toweius spp. accompanied by a gradual decrease in Coccolithus pelagicus/subpertusa indicates a return to a cooler, mesotrophic to eutrophic environment.
Cretaceous Research, 2009