Walvis Ridge barrier: its influence on palaeoenvironments and source rock generation deduced from ostracod distributions in the early South Atlantic Ocean

Dingle, R. V.. 1999 Walvis Ridge barrier: its influence on palaeoenvironments and source rock generation deduced from ostracod distributions in the early South Atlantic Ocean. Geological Society, London, Special Publications, 153 (1). 293-302. https://doi.org/10.1144/GSL.SP.1999.153.01.18

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Abstract/Summary

The early South Atlantic was subdivided latitudinally by the proto-Walvis Ridge, which separated early Cretaceous open marine conditions in the south from non-marine environments to the north. Changes in the palaeogeography, which can be monitored by the distribution of ostracod assemblages, determined the establishment of a wide variety of depositional environments, including evaporitic and total organic carbon-rich facies. Limited northward marine influxes across the barrier are postulated for mid-Aptian time, while largescale southward migrations of marine ostracods from the northern sector occurred in early Cenomanian and/or Turonian times. The latter established cosmopolitan faunas in the southern Atlantic and effectively marked the breakdown of the Walvis Ridge as a physical barrier to north-south migrations, although possible oceanographic factors militated against longitudinal faunal movements. Variations in the composition of ostracod assemblages during so called ‘oceanic anoxic events’ and the production of potential source rocks is briefly reviewed.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1144/GSL.SP.1999.153.01.18
Programmes:	BAS Programmes > Pre 2000 programme
ISSN:	0305-8719
Additional Keywords:	Ostracoda, Cretaceous, South Atlantic, rift, palaeogeography
Date made live:	14 Oct 2013 10:20 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/503168

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