First record of the Cenomanian-Turonian Oceanic Anoxic Event (OAE-2) in the eastern Rub’ Al Khali Basin by means of elemental chemostratigraphy

Abstract

Numerous locations in Eastern Arabia contain organic-rich Cenomanian-Turonian (C/T) sediments, including Qatar, UAE, and Oman. The contrast between organic-rich and organic-lean anoxic facies, as well as the local to regional distribution of the C/T facies, is shown here. These regions are confirmed to be rich in organic material using bore-hole data, and our study has precisely identified their limits. The inorganic geochemical investigations focus on the Cenomanian-Turonian Mishrif Member of the upper Wasia Formation. This elemental chemostratigraphy approach is investigated as a timely and cost-effective substitution for carbon isotope determination during hydrocarbon exploration and development phases. The study reveals information about how the palaeoceanography of intrashelf basin changed throughout the Cenomanian-Turonian time. The use of discrete redox-sensitive and primary productivity along with sensitive trace element data and detrital-related elements is demonstrated as one of the best methods to emphasise the reducing conditions that reigned during the OAE-2 in the area. The redox-sensitive proxies show three broad pulses of anoxic to euxinic conditions associated with the bottom water, separated by dysoxic to oxic conditions in the Cenomanian-Turonian Mishrif Member. Either the basin geometry or the expansion of an oxygen minimum zone (OMZ) is the main factor that controlled the bottom redox condition distribution during the deposition of the Mishrif Member. Elemental chemostratigraphy has been utilised to identify and characterise the OAE-2 phases in the study area in the absence of carbon isotope perturbation data.