Organic carbon accumulation in Bannock Basin: Evaluating the role of productivity in the formation of eastern Mediterranean sapropels

Abstract

Three sediment cores from Bannock Basin, a hypersaline anoxic basin in the eastern Mediterranean, have been studied to evaluate the importance of productivity on organic carbon accumulation and sapropel formation in this region. Organic carbon accumulation rates were determined for two cores from within the anoxic, hypersaline zone and for one core from the oxygenated portion of this basin. Organic carbon accumulation. Rates are higher by an order of magnitude in the surficial sediments of the anoxic zone due to better preservation. An empirically derived preservation factor, which allows calculation of paleoproductivity during the deposition of the most recent sapropel (SI), indicates that productivity increased by an order of magnitude during the formation of SI. We conclude that increased productivity was coupled with a density stratification and a circulation reversal in the eastern Mediterranean, which together led to sapropel formation.