Geochemistry on sapropel deposition in the eastern Mediterranean from cores TTR-GL94 and M25/4-KL11

The Ba-enriched interval is broader than the organic-carbon-rich interval of this sapropel. We suggest that the Ba-enriched horizon records the original thickness of the sapropel prior to subsequent partial oxidation.

The main carrier of Ba is barite, as microcrystals (0.5-5 µm ) having a morphology characteristic of marine barite, particularly abundant beneath high productivity regions. Ba concentrations do not change at the sapropel layer oxidation front and diagenetic barite crystals are absent, thus the Ba-enriched layer reflects original oceanic conditions of increased biological productivity during sapropel deposition and not diagenetic Ba remobilization.