Examining Biomarkers In Sedimentary Deposits Of Ocean Anoxic Event 2

Abstract

Oceanic Anoxic Event 2 occurred near the Cenomanian-Turonian boundary ca. 93.5 million years ago. Global warming and an enhanced hydrological cycle fueled ocean productivity, resulting in worldwide deposition of organic carbon-rich black shales. Some of the best exposures of OAE-2 are in the Apennine mountains in Italy. The purpose of this project was to investigate whether black cherts from these localities have better preservation of biomarkers that record climate conditions during the event than black shales. We examined seven samples that were collected from two different outcrops: one in Furlo, Italy and another at the Contessa quarry, about 30 miles away. From the data, it was found that the preserved fatty acids were likely from marine biomass rather than terrestrial life. These fatty acids also revealed that the cherts were better preservers than shales for the fatty acids. By evaluating the GDGTs, it was found that the average sea surface temperature was 41.2°C.