Foraminiferal biostratigraphy, paleoenvironment and paleobiogeography of Cenomanian-Lower Turonian shallow marine carbonate platform in west central Sinai, Egypt

摘要

The Cenomanian-Early Turonian succession exposed in west central Sinai was carefully studied for their foraminiferal content. Lithostratigraphically, this carbonate platform interval in the studied area include the Raha Formation (Early-Middle Cenomanian) and Abu Qada Formation (Late Cenomanian-Early Turonian). One hundred and one species belonging to 69 genera and 41 families are identified. Out of this content, 86 species belong to benthic foraminifera, and 16 belong to the planktonic ones. One larger benthic foraminiferal species namely Biconcava ribbata Shahin (n. sp.) is considered here as new species. Four large benthic foraminiferal zones and one planktonic foraminiferal zone are recognized and correlated with their equivalents inside and outside Egypt. The successive last and first appearances of most large agglutinated and porcellaneous benthic foraminifera refer to successive bioevents. The Heterohelix shift below the Cenomanian-Turonian boundary is an excellent biomarker for global event correlation for oxygen minimum zone. Also the scarcity or even the disappearance of larger benthic foraminifera in this interval can be interpreted as the final stages of the Late Cenomanian-Early Turonian Oceanic Anoxic Event 2. The wide paleobiogeographic distribution of the recorded larger foraminifera reveals that there was a strong affinity and direct connection allover the Tethyan Realm.