Middle Cretaceous black shales at Site 530 in the southeastern Angola Basin.

Abstract

The middle Cretaceous black shale interval at Site 530 is 170m thick and late Albian to Coniacian in age. Study of the sedimentary and biogenic structures and composition and review of paleoceanographic conditions in the Angola Basin indicate that a complex interplay of processes controlled black shale accumulation. Relatively low oxygen concentrations in sediment and bottom waters occurred periodically, and conditions locally may have been anoxic or near anoxic both in the basin and on the continental margin. Pelagic, hemipelagic, and turbiditic depositional processes all operated to varying degrees at different times.-from Authors