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

Initial Reports of the D.S.D.P.
By:  and 

Links

Abstract

The middle Cretaceous black shale interval at Site 530 is 170 m thick and late Albian to Coniacian in age. The organic-carbon-rich sediments occur as 260 separate beds (average 4 cm, maximum 60 cm thick) and make up less than 10% of the recovered section. Associated lithologies are greenish, grayish, and reddish mudstones, marlstones, and rare limestones. Organic-carbon contents of the black shales average about 5% (maximum 16%), and of the interbedded sediments, less than 0.5%. Careful 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.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Middle Cretaceous black shales at Site 530 in the southeastern Angola Basin
Series title Initial Reports of the D.S.D.P.
DOI 10.2973/dsdp.proc.75.120.1984
Volume 75
Issue 2
Year Published 1984
Language English
Publisher Texas A&M D.S.D.P.
Contributing office(s) Geosciences and Environmental Change Science Center
Description 9 p.
First page 809
Last page 817
Other Geospatial Drilling Site 530, 531, 532
Google Analytic Metrics Metrics page
Additional publication details