Conspicuous seismic reflections in Upper Cretaceous sediments as evidence for black shales off South Africa


Contact
Gabriele.Uenzelmann-Neben [ at ] awi.de

Abstract

The Upper Cretaceous is commonly associated with greenhouse climate, Oceanic Anoxic Events (OAE), and the ongoing break up of Gondwana, which resulted in strong variations of the oceans currents flow paths and climate change. Little is known about these changing conditions, in particular south of South Africa. A high resolution seismic reflection data set from the submarine Transkei Basin off South Africa revealed various depositional stages for this region for the past ~ 90 Ma. In these seismic sections, a recurrently appearing high amplitude horizon within weak to homogeneous Upper Cretaceous reflections was observed. Due to the inaccessibility of any drill hole data from the Transkei Basin and adjacent regions, the origin of this reflector is difficult to specify. It is roughly dated at ~ 80 Ma - ~ 85 Ma, which falls within the last big OAE in Upper Cretaceous (OAE 3). A seismostratigraphic analysis led to an exclusion of several features as the origin for this reflector, such as gas hydrates, opal bearing horizons or biogenic oil. Other possible features, such as lithologic variations, intrusions or black shales are discussed in more detail. According to its appearance and reflection characteristics it could possibly be the first report of black shales in this region.



Item Type
Conference (Invited talk)
Authors
Divisions
Programs
Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
Jahrestagung der Deutschen Geophysikalischen Gesellschaft, Kiel mar.
Eprint ID
20159
Cite as
Uenzelmann-Neben, G. and Schlüter, P. (2009): Conspicuous seismic reflections in Upper Cretaceous sediments as evidence for black shales off South Africa , Jahrestagung der Deutschen Geophysikalischen Gesellschaft, Kiel mar .


Share

Research Platforms
N/A

Campaigns


Actions
Edit Item Edit Item