Environmental perturbations during the Oceanic Anoxic Event 1a (Early Aptian) in the epeiric sea of the Eastern Russian Platform

Abstract

Toxic environments are reconstructed during the OAE 1a in the epeiric sea of the Northeastern Peri-Tethys. Very high toxicity of sediments in conjunction with lack of oxygen could therefore result in conditions not suitable for benthic fauna dwelling. Black shales should be considered as one of the most important sources of the light carbon isotope in the atmosphere and oceans and the strongest emitters of methane. These data should be taken into account while estimating greenhouse effect in the Early Aptian. The environmental models constructed for the pre-OAE-1a, OAE-1a, and post-OAE-1a conditions may help to better understand modern climate changes using comprehensive analyses of oxic and euxinic conditions in the oceans and interpret the greenhouse processes from the geological past to the present time.