Ashraf MT Elewa

Prof. Dr. Ashraf MT Elewa

orcid

Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2004 in Palaeogeography, Palaeoclimatology, Palaeoecology
Verified
Journal Article
Closed access
AEAshraf MT Elewa
Ashraf MT Elewa

1 August 2018 in Marine Pollution Bulletin
Verified
Journal Article
Closed access
Ahmed Awad AbdelhadyAhmed Awad Abdelhady
Ahmed Awad Abdelhady
EAEsraa Abdelrahman
Esraa Abdelrahman
AEAshraf MT Elewa
Ashraf MT Elewa
JFJiawei Fan
Jiawei Fan
Shengrui ZhangShengrui Zhang
Shengrui Zhang
JXJule Xiao
Jule Xiao


1 February 2020 in Journal of African Earth Sciences
Verified
Journal Article
Closed access
AEAshraf MT Elewa
Ashraf MT Elewa
Ahmed Awad AbdelhadyAhmed Awad Abdelhady
Ahmed Awad Abdelhady

1 March 2018 in Journal of African Earth Sciences
Verified
Journal Article
Closed access
Ahmed MansourAhmed Mansour
Ahmed Mansour
OMOmar Mohamed
Omar Mohamed
STSameh Tahoun
Sameh Tahoun
AEAshraf MT Elewa
Ashraf MT Elewa

7 December 2020 in Minerals
Verified
Journal Article
Open access
PDF file
Ahmed MansourAhmed Mansour
Ahmed Mansour
Thomas GentzisThomas Gentzis
Thomas Gentzis
MWMichael Wagreich
Michael Wagreich
STSameh Tahoun
Sameh Tahoun
AEAshraf MT Elewa
Ashraf MT Elewa
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 reconstructions. Highly diverse assemblage of marine palynomorphs along with elemental proxies that relate to carbonates and siliciclastics and bulk carbonate δ13C and δ18O from the Upper Cretaceous Abu Roash A Member were used to reconstruct short-term sea level oscillations in the Abu Gharadig Basin, southern Tethys. Additionally, we investigated the relationship between various palynological, elemental, and isotope geochemistry parameters and their response to sea level changes and examined the link between these sea level changes and Late Cretaceous climate. This multiproxy approach revealed that a long-term sea-level rise, interrupted by minor short-term fall, was prevalent during the Coniacian-earliest Campanian in the southern Tethys, which allowed to divide the studied succession into four complete and two incomplete 3rd order transgressive-regressive sequences. Carbon and oxygen isotopes of bulk hemipelagic carbonates were calibrated with gonyaulacoids and freshwater algae (FWA)-pteridophyte spores and results showed that positive δ13Ccarb trends were consistent, in part, with excess gonyaulacoid dinocysts and reduced FWA-spores, reinforcing a rising sea level and vice versa. A reverse pattern was shown between the δ18Ocarb and gonyaulacoid dinocysts, where negative δ18Ocarb trends were slightly consistent with enhanced gonyaulacoid content, indicating a rising sea level and vice versa. However, stable isotope trends were not in agreement with palynological calibrations at some intervals. Therefore, the isotope records can be used as reliable indicators for reconstructing changes in long-term sea level rather than short-term oscillations.