Carbon isotope stratigraphy, magnetostratigraphy, and Ar-40/Ar-39 age of the Cretaceous South Atlantic coast, Namibe Basin, Angola

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TitreCarbon isotope stratigraphy, magnetostratigraphy, and Ar-40/Ar-39 age of the Cretaceous South Atlantic coast, Namibe Basin, Angola
Type de publicationJournal Article
Year of Publication2014
AuteursStrganac C, Salminen J, Jacobs LL, Polcyn MJ, Ferguson KM, Mateus O, Schulp AS, Morais MLuisa, Tavares Tda Silva, Goncalves AOlimpio
JournalJOURNAL OF AFRICAN EARTH SCIENCES
Volume99
Pagination452-462
Date PublishedNOV
Type of ArticleArticle
ISSN1464-343X
Mots-clésAfrica, Atlantic, Chemostratigraphy, Cretaceous, Magnetic polarity stratigraphy, Stable carbon isotopes
Résumé

We present the delta C-13 and paleomagnetic stratigraphy for marine strata at the coast of southern Angola, anchored by an intercalated basalt with a whole rock Ar-40/Ar-39 radiometric age of 84.6 +/- 1.5 Ma, being consistent with both invertebrate and vertebrate biostratigraphy. This is the first African stable carbon isotope record correlated to significant events in the global carbon record spanning the Late Cenomanian to Early Maastrichtian. A positive similar to 3 parts per thousand excursion seen in bivalve shells below the basalt indicates the Cenomanian-Turonian Boundary Event at 93.9 Ma, during Oceanic Anoxic Event 2. Additional excursions above the basalt are correlated to patterns globally, including a negative similar to 3 parts per thousand excursion near the top of the section interpreted as part of the Campanian-Maastrichtian Boundary Events. The age of the basalt ties the studied Bentiaba section to a pulse of Late Cretaceous magmatic activity around the South Atlantic and significant tectonic activity, including rotation, of the African continent. (C) 2014 The Authors. Published by Elsevier Ltd.

DOI10.1016/j.jafrearsci.2014.03.003