Ahmed Mansour

Ahmed Mansour
Southwest Petroleum University

PhD

About

61
Publications
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614
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Publications

Publications (61)
Article
During the late Pliensbachian-early Toarcian interval (Early Jurassic), multiple environmental perturbations and changes in biogeochemical cycles severely impacted marine and continental ecosystems. Periods of environmental change occurred across the Pliensbachian-Toarcian boundary and in the early Toarcian and coincide with rising seawater tempera...
Article
The Eocene-Oligocene transition was marked by a notable shift in global climate patterns, from greenhouse to icehouse conditions and continental aridification, consistent with a change in vegetation cover. Tectonic uplift and the collision between the Indian and Asian plates, as well as sea regression, were of the potential derivers of global clima...
Article
The Carnian Pluvial Episode (CPE; ∼233 Ma) is marked by global warming associated with an intensified hydrological cycle and increased siliciclastic input, coinciding with a widespread crisis in carbonate production. It was further linked to the eruption of the Wrangellia Large Igneous Province (W-LIP), seawater hypoxia, and significant biotic turn...
Article
The Guadalupian (Middle Permian) witnessed a significant biocrisis or mass extinction which wiped out complex and large benthic faunas previously flourished in the long-term Carboniferous and Early-Middle Permian. The triggered pattern of environmental factors such as marine anoxia and volcanism on the mass extinction is still unclear. Here, we pre...
Article
The early to middle Cenomanian was marked by a predominant greenhouse world, with diminished ice sheets, disruptions in the global carbon cycle, and long-term eustatic sea-level rise, which led to the development of vast epicontinental and shallow shelf seas. These oceanographic and environmental instabilities influenced climate evolution and the a...
Article
In Sichuan Basin, uranium (U) and thorium (Th) are more abundant in organic-rich shale than in granitic rocks, suggesting that organic-rich shale is a significant source rock for helium (He). However, the He generation potential of organic-rich shale and He enrichment mechanisms in shale gas fields remain limited in understanding. Based on the He,...
Article
Full-text available
This study focuses on the PS8 well in the Penglai Gas Field (Sichuan Basin), a newly identified key exploration area, where high-yield gas testing has been achieved from the Ediacaran Fourth Member of the Dengying Formation. Comprehensive analyses of drilling cores, cuttings, thin sections, analytical data, well logging, and production testing data...
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The Tibetan Plateau plays a crucial role in both Asian and global geomorphology and climate dynamics. However , the precise mechanisms through which its deep geodynamic processes influence surface systems have remained elusive. Here, we present a novel model that can be used to evaluate these processes, employing a comprehensive approach that incor...
Article
The relationship between the uplift of the Tibetan Plateau and the aridification of eastern Asia during the middle to late Eocene is still controversial, primarily due to the lack of high-resolution chronological frameworks for global isochronous comparisons. Here, we present a new high-resolution astrochronology for the Eocene Suonahu Formation in...
Article
Major sea-level cycles occurred in the Cenomanian-early Turonian greenhouse world and impacted depositional conditions and ecosystems across the paleo-shelf seas. These sea-level cycles have been interpreted from various paleogeographic settings around the globe, such as the Western Interior Seaway (North America), the Proto-North Atlantic, Western...
Article
The late Albian-Cenomanian (100.5-93.9 Ma) is considered a greenhouse world without permanent ice caps and with high eustatic sea levels. The high sea-level led to the flooding of low-lying coastal plains and the formation of extensive shallow shelf seas. Depositional conditions and ecosystems at these marginal and shallow shelf settings were affec...
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The comment by Yin (2024) referred to the systematic morphology and identification of the newly recovered in situ ammonite assemblage Tiltoniceras sp. and Hildoceratidae sp. from the Bilong Co section in the Qiangtang Basin. Yin (2024) suggests that Tiltoniceras sp. should be assigned to Oxycerites aspidoides. Upon re-examination of our paper and t...
Article
The Bohai Bay Basin is one of the giant petroliferous, non-marine rift basins in China, which was subjected to complex tectonic activities during the Cenozoic. The Nanpu Depression in the Huanghua sub-basin in the northern part of the Bohai Bay Basin was controlled by Paleogene rifting and increased subsidence. During this period of time, the Shahe...
Article
The Oceanic Anoxic Event 1a (OAE1a), or the Selli Event, occurred in the early Aptian (~120 Ma) and represents an episode of global carbon-cycle perturbation caused by substantial greenhouse gas emissions, leading to profound environmental and climatic changes. However, our understanding of the impact of OAE1a in the eastern Tethys region, particul...
Article
The Carboniferous was a period of intense environmental perturbations, climate changes between greenhouse and icehouse, eustatic sea level change, and accumulation of organic carbon-rich sediments. At this time, the Tyler Formation was deposited in the midcontinent USA. A detailed palynological analysis of the Tyler Formation revealed a highly dive...
Article
During the Late Cretaceous (Cenomanian), significant disruptions in the carbon cycle, global warming, and episodes of oceanic anoxia occurred, leading to the deposition of organic carbon-rich sediments. In well BED2-3, located in the BED2 gas field within the Abu Gharadig Basin (north Western Desert, Egypt), the lower-to-middle Cenomanian Bahariya...
Article
The late Albian-Cenomanian (mid-Cretaceous) greenhouse world was characterized by major eustatic sea-level variations and environmental change. However, little is known about the drivers of Cenomanian sea-level change. This work discusses stratigraphic trends in the palynofacies and palynomorph composition for upper Albian-Cenomanian strata from th...
Article
The Qiangtang Basin is one of the largest Mesozoic petroliferous basins in China that is still unexploited for the petroleum industry. The basic geological issues and synthesis of the Qiangtang Basin related to the Tethyan evolution are still poorly understood. This volume presents 20 research papers to address the tectonic settings, basin evolutio...
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The Jurassic Period was a significant phase of variable organic matter accumulation in paleo-shelf areas of the southern Tethys (Egypt). Reconstructing the paleoredox conditions, paleo-climate, and weathering intensity, along with the role of terrigenous sediment flux and mineralogi-cal maturity, is important for understanding basin infill history...
Article
The Eocene-Oligocene transition was a time of major climate instability and a shift from an ice-free world to a predominant icehouse climate. Identifying the ancient glacial deposits and their associated sedimentary structures are of paramount significance for understanding the Earth’s climate in the Cryogenian Period. Ice-induced sedimentary struc...
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Full-text available
The Bilong Co oil shale is one of the most significant source rocks in the Mesozoic Qiangtang Basin (Northern Tibet); however, its absolute chronology remains controversial. In this study, in situ carbonate U-Pb isotope dating analysis was carried out for the first time. Detailed field geological investigations yielded some age-diagnostic ammonites...
Article
Global climate change has profound implications for human survival and prosperity. The Carnian (early Late Triassic, ~233 Ma) was a time of global environmental perturbations, climatic change, and biotic turnover, commonly known as the Carnian Pluvial Episode (CPE). However, the understanding of possible triggering mechanisms of the CPE is still pa...
Article
The dolostone in the south Qiangtang depression has been proven to be a favourable reservoir rock of the famous Longeni-Angdaerco palaeo-reservoir, being of great significance for oil and gas exploration in the Qiangtang basin. However, its geochronology and diagenetic process are still controversial. In particular, the previous interpretation that...
Chapter
The Cretaceous Period (ca. 143-66 Ma) attested to successive phases of regional tectonic activities and large-scale submarine volcanism resulting in increased atmospheric CO2 (pCO2) concentrations, enhanced greenhouse climate and global warming, surface water bioproductivity, and well-developed pore and bottom water anoxia, especially during the mi...
Article
Oceanic acidification has long been suggested as a potential environmental trigger of marine ecosystem collapse in the Earth’s history. However, evidence for oceanic acidification as an important controlling mechanism of the end-Triassic mass extinction is still limited. Here, the first coupled carbon- and calcium-isotope records across the Triassi...
Article
Full-text available
The extensive thinning and destruction of North China Craton (NCC) during the Early Cretaceous led to the development of numerous rift basins and petroleum systems. However, the specific relationship between NCC evolution and hydrocarbon generation and accumulation in these sedimentary basins is still unclear. In this study organic geochemistry and...
Article
The Toarcian Oceanic Anoxic Event (T-OAE) is characterized by significant environmental perturbation and climatic instabilities due to a substantial release of greenhouse gases. Several investigations of the T-OAE were conducted based on reliable and well-developed integration of multi-proxy approaches, revealing the global distribution of this eve...
Article
The third member of the Paleogene Shahejie Formation (Es3) in the Dongpu Depression, China, was studied to interpret its paleoenvironment through a series of trace element proxies, to reveal paleosalinity conditions, to elucidate on the hydrological conditions of the paleolake using carbon and oxygen stable isotopes, and to investigate the effects...
Article
Full-text available
The Middle Jurassic was a time of marginal to shallow shelf settings dominated by organic matter-rich deposition in northern Egypt, southern Tethys. Paleoenvironmental and sequence stratigraphic reconstructions are of paramount significance for a better understanding of basin history and related reservoirs and source rock units. For this purpose, a...
Article
The early Toarcian oceanic anoxic event (T-OAE) is characterized by major changes in the marine and terrestrial environments, which is possibly related to the accelerated hydrological cycle. However, the impact of hydrological cycling on continental vegetation is poorly constrained. Here, we present biomarker evidence that suggests an accelerated h...
Article
The early Aptian Oceanic Anoxic Event (OAE 1a, ∼120 Ma) represents an episode of severe paleoenvironmental disturbance during the Cretaceous, marked by the widespread deposition of organic matter (OM)-rich sediments. The OAE 1a has been extensively studied in the Pacific, Boreal, and western and southern Tethyan regions. However, limited studies of...
Article
Jurassic is characterized by a highly fluctuating climate. During the late Middle to Late Jurassic, Northwest China, including the Qaidam Basin, underwent a major climate transition from humid to arid conditions. In this study, we focused on the climate transitional interval (Bathonian Stage, Jurassic) and conducted high-resolution palynological an...
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The Middle Jurassic in the northWestern Desert, Egypt, was a time of complex tectonics and increased environmental perturbations attributed to the predominant sedimentation of organic carbon-rich fine siliciclastic and carbonate deposits of the Khatatba Formation. Although some studies have addressed the hydrocarbon potential and source rock charac...
Article
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The nature of glaciation (bipolar vs. unipolar) during the Eocene−Oligocene transition (EOT) remains unresolved. Here, we report the occurrence of frost marks, ice-rafted debris (IRD), and glendonites from the Upper Eocene to Lower Oligocene Niubao Formation (Fm.) deposited in a proglacial lake above glaciolacustrine conglomerates and diamictite fa...
Article
The beginning of the Late Cretaceous (Cenomanian) attested to a major marine transgression interrupted by sea level falls in north Africa, which led to significant environmental perturbation and widespread accumulation of organic matter-rich sediments. During this period, northern Egypt was located at the southern edge of the Tethys Ocean and depos...
Article
The Early Cretaceous (Albian) was a time of equatorial to polar temperature warming and increased environmental perturbations of the global carbon cycle and oceanic anoxia, which resulted in the widespread accumulation of organic carbon-rich sediments. During the Albian, the southern margin of the Tethys Ocean was characterized by marginal to shall...
Article
Sequence stratigraphy is a commonly used approach to understand basin-fill history and the occurrence of conventional reservoir and/or probable source rocks. Reconstructing a sequence stratigraphic framework in carbonates, marls, and organic-rich mudstones is challenging due to environmental, petrophysical, and sedimentological variations that can...
Chapter
The southern Qiangtang Basin located in the central Tibetan Plateau of the eastern Tethys is among the most significant petroliferous provinces in China. In this chapter, lower Toarcian sediments represented by thick oil shale succession from the Bilong co area, were studied. Geochemical screening, organic petrographic, and palynological analyses w...
Article
This study investigates the Bahariya Formation using 39 rock-cutting samples from the Abu Gharadig Basin in the north Western Desert, Egypt. An approach combining palynomorph composition and palynofacies analysis with lithological composition and geophysical gamma ray log values is used to assess biostratigraphic age constraints, prevalent depositi...
Article
Full-text available
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, an...
Article
Full-text available
Widespread deposition of siliciclastic sediments with consequent alternations between fine-grained siltstones and shales versus coarse-grained sandstones in the north Western Desert of Egypt provides an archive for mid-Cretaceous sea-level oscillations. This study presents elemental geochemical data as well as palynofacies and palynomorph component...
Article
The Toarcian Oceanic Anoxic Event (T-OAE; Early Jurassic, ca. 183 Ma) represents an intense Mesozoic organic carbon burial event that was associated with the formation of oxygen-deficient conditions at paleo-shelf seas, as well as in lacustrine settings. Global scale increase in organic carbon accumulation occurred in connection with profound chang...
Article
During the Late Devonian, the Michigan Basin in the Eastern Interior Seaway was characterized by phases of well-developed bottom water anoxia, triggering extensive accumulation of organic matter-rich black shales. Palynological analysis for paleoenvironmental reconstruction and biostratigraphy of the Upper Devonian rocks has been previously perform...
Article
The Coniacian-Santonian (C-S) was a time of differentiation in marine sedimentation, characterized by organic carbon (OC)-rich black shales and carbonates interpreted as the last oceanic anoxic event, OAE3, versus OC-poor white/reddish limestones, chalk, and claystones known as Cretaceous Oceanic Red Beds (CORBs). Based on compiled geochemical and...
Article
Inadequate delineation of reservoir-heterogeneities, along with charge-timing confirmation, can considerably mislead exploration-development phases of petroleum. Therefore, precisely depicting the reservoir-architecture is crucial for avoiding exploration failures. To this end, integrated approach of various facies analysis and modeling-related dis...
Article
An integrated approach based on organic petrographic and geochemical proxies along with palynological and palynofacies analysis were employed using 24 rock samples representing the upper part of the Quse and Sewa formations in the southern Qiangtang Basin, Tibetan Plateau, SW China. This interval was deposited during the Early Jurassic Toarcian Oce...
Article
The Late Cretaceous epoch witnessed significant changes in climate and considerable perturbations in the global carbon cycle, among others leading to Oceanic Anoxic Events (OAEs). Investigating the paleoceanographic setting in the southern Tethys (northern Egypt) is critical for a better understanding of the triggering mechanisms that occurred duri...
Article
Full-text available
Widespread deposition of pelagic-hemipelagic sediments provide an archive for the Late Cretaceous greenhouse that triggered sea level oscillations. Global distribution of dinoflagellate cysts (dinocysts) exhibited a comparable pattern to the eustatic sea level, and thus, considered reliable indicators for sea level and sequence stratigraphic recons...
Article
The Gulf of Suez area in eastern Egypt is one of the most prospective and promising hydrocarbon provinces all over the world. Sixty drill cuttings samples of the Upper Cretaceous Raha Formation (70–120 m) have earlier been processed for their palynomorph and palynofacies contents, including 36 geochemically screened samples for their source-rock po...
Article
Rock-Eval pyrolysis/TOC, petrographic, and geochemical data available in the public domain for a total of 296 core and 243 drill cuttings samples from the Albian-early Cenomanian Kharita and Bahariya formations of four main basins, Shushan, Abu Gharadig, Matruh and Dahab-Mireir, were reviewed. This review provides a comprehensive overview to unders...
Article
The mid-Cretaceous period was a time of abnormal polar temperature warming and consequent global oceanic anoxia that enhanced the widespread accumulation of organic matter-rich marine sediments. The current contribution focuses on the late Albian oceanic anoxic subevent 1d (OAE 1d) that represents a period of increased perturbation of the global ca...
Article
Geochemical and palynological proxies were determined for 31 samples representing the upper Coniacian-lowermost Campanian Abu Roash A Member, collected from the BED2-3 well. This was done to assess the prevailing paleoredox conditions, productivity levels, and water-column settings to: (1) understand controls and mechanisms related to accumulation...
Article
Geochemical and palynological proxies were determined for 31 samples representing the upper Coniacian lowermost Campanian Abu Roash A Member, collected from the BED2-3 well. This was done to assess the prevailing paleoredox conditions, productivity levels, and water-column settings to: (1) understand controls and mechanisms related to accumulation...
Article
The topmost Lower and Middle Jurassic formations of organic-rich clastics with minor carbonate deposits were recognized as very significant source/reservoir rocks in the North Western Desert of Egypt. Although several studies are devoted to their source rock characteristics and petroleum potential, the depositional paleoenvironment and paleoredox c...
Article
This study presents a high-resolution palynological analysis for the Abu Roash ‘A’ Member in the hydrocarbon-rich Abu Gharadig Basin, North Western Desert, Egypt. Thirty-one rock samples, spanning the upper Coniacian to lower Campanian Abu Roash ‘A’ Member (180 m) from the Badr El Din (BED)2-3 borehole, were investigated. Highly diverse and well-pr...
Article
This work presents the first discovery of reworked palynomorphs in Cretaceous deposits of the Gulf of Suez, Egypt. Our examination of palynomorphs contained within the productive Raha Formation reveals a distinctive record of reworked palynomorphs of Late Palaeozoic age. As provenance indicators, these reworked palynomorphs could provide clues to t...
Article
Full-text available
The current study presents a fully qualitative palynological investigation carried out on the Raha Formation encountered from three wells in the Bakr Oil Field of the Gulf of Suez, Egypt. Around 30 species of pteridophytic spores, 26 species of an-giosperm pollen, 24 species of gymnosperm pollen and 27 species of dinoflagellate cysts have been reco...
Article
The current contribution illustrates the advantage of the use of quantitative palynological data to palaeoenvironmentally differentiate the similar-looking monotonous, thick clastic interval of the Kharita, Bahariya and Abu Roash “G” units in Gindi Basin, Egypt. The present study aims also to the utilization of the upper Albian-Cenomanian quantitat...
Article
Full-text available
Herein, we reply to the allegations made by Anan et al. (2018) who claimed that the rhythmic signature of Pediastrum originally recorded and interpreted for the first time by (Tahoun et al., 2017), is a simulation of the work of El Atfy et al. (2017). This is not possible because we submitted our manuscript (which comes from an earlier version prev...
Article
Sixteen samples from the “E” to “B” members of the Abu Roash Formation encountered in the Beni Suef Basin, Eastern Desert of Egypt were palynologically analyzed for palaeoenvironmental and sequence stratigraphic investigations. The integrated palynofacies and lithofacies analysis of the studied section indicates deposition of five alternating regre...

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usually, the total sulfur content is slightly higher in carbonate and calcareous shale facies than in black shale facies,... why??

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