Origin and Evolution of Natural Diversity;Proceedings


Depositional Environments Revealed From Biomarkers in Sediments Deposited During the Mid-Cretaceous Oceanic Anoxic Events (OAEs) in the Vocontian Basin (SE France)

Okano, Kazuki;Sawada, Ken;Takashima, Reishi;Nishi, Hiroshi;Okada, Hisatake

Permalink : http://hdl.handle.net/2115/38471
KEYWORDS : OAE;Thiophene;Sulfur content;Redox condition;Terrestrial input


Biomarker and total sulfur (TS) analyses were carried out on laminated black shales and massive marls collected from Goguel level (OAE1a) and the Kilian and the Paquier levels (OAE1b) in the Vocontian Basin in southeast France. Total sulfur content and concentrations of thiophenes are abundant in the Goguel level, whereas furans and retene, which are originated from terrestrial plants, are predominant in the Kilian and the Paquier levels. These results suggests the expansion of intense anoxic waters to deep ocean during the deposition of Goguel level rather than during the periods covered by the Kilian and the Paquier levels. In contrast, the Kilian and the Paquier sediments are characterized by a large amount of terrestrial input. Therefore, it is inferred that OAE1a was associated with supplying a large amount of sulfur to the ocean, possibly by active volcanisms, whereas OAE1b was caused by a large amount of terrestrial matter and fresh water input.