Early Cretaceous Oceanic Anoxic Events in Rudist-Bearing Succession, North Egypt

Abstract

The δ13C curve of the Late Barremian-Late Albian rudist-bearing succession of Gabal Raghawi, in north Sinai, can be subdivided into 22 characteristic Carbon segments (C1–C22). The δ13C record from the studied section is consistent with that previous documented in other sections of the Tethyan realm. This correlation allows us to place the Barremian-Aptian boundary at the positive shift in δ13C at the contact between Carbon segments C1 and C2. The Oceanic Anoxic Event 1a (OAE1a), represented by the segments C3–C6, is recognized below the Early-Late Aptian boundary and is identified in different Tethyan sections at the D. forbesi Zone. The Aptian-Albian boundary is located above the Acanthohoplites nolani horizon within the Oceanic Anoxic Event 1b (OAE1b). During the early Late Albian, the positive Carbon isotope excursion at the topmost of C15 and C16–C17 segments shows similarities to the segments C16–C17 of the Tethys and corresponds to the Oceanic Anoxic Event 1c (OAE1c). The OAE1d occurred directly below the Albian/Cenomanian boundary within the Mortoniceras inflatum Zone.