230 D17. Recent Advances in Sedimentology and Stratigraphy (Posters)

Wednesday, 18 October 2023
8:00 AM - 5:30 PM
Hall B

EXPRESSION OF OAE-2 IN THE WEST AFRICAN BENUE TROUGH

Paper number: 230-39
Program: Technical Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

Organic carbon-rich shales deposited under anoxic conditions have been found globally during the Oceanic Anoxic Event 2 (OAE 2) at the Cenomanian – Turonian boundary (~93.5 Ma). The anoxia has been postulated to have been triggered by eruption of submarine Large Igneous Province. Although, OAE 2 occurrence has been global, local structural and paleogeographic variations have strong impact on the evolution of anoxia across the globe. Here, we present data from a new site from the west African Upper Benue Trough, a cretaceous rift basin that formed from the separation of Africa and South America during the Mesozoic and was part of a transcontinental seaway that connected the Atlantic Ocean to the paleo Tethys during the Cenomanian marine transgression. The OAE 2 deposits within the Benue trough is a 3 m black shales interval of the Pindiga Formation. Carbon isotope analysis shows a 3‰ δ13C positive excursion characteristic of the OAE 2 interval and conclusively showing for the first-time evidence of OAE 2 interval within the basin. We also measured trace and redox sensitive elements to further understand the development of anoxia within the Benue Trough.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-394944

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