Paleogeographic evolution of the central segment of the South Atlantic during Early Cretaceous times: Paleotopographic and geodynamic implications

Type Article
Date 2013-09
Language English
Author(s) Chaboureau Anne-Claire1, 2, Guillocheau Francois1, Robin Cecile1, Rohais Sebastien2, Moulin MarylineORCID3, Aslanian DanielORCID4
Affiliation(s) 1 : Univ Rennes 1, CNRS, Geosci Rennes UMR6118, F-35042 Rennes, France.
2 : IFP Energies Nouvelles, F-92852 Rueil Malmaison, France.
3 : Univ Lisbon, Fac Ciencias, IDL, P-1749016 Lisbon, Portugal.
4 : IFREMER, Dept Marine Geosci, F-29280 Plouzane, France.
Source Tectonophysics (0040-1951) (Elsevier Science Bv), 2013-09 , Vol. 604 , P. 191-223
DOI 10.1016/j.tecto.2012.08.025
WOS© Times Cited 71
Keyword(s) South Atlantic Ocean - central segment, Rift, Early Cretaceous, Paleogeography, Geodynamic
Abstract The geodynamic processes that control the opening of the central segment of the South Atlantic Ocean (between the Walvis Ridge and the Ascension FZ) are debated. In this paper, we discuss the timing of the sedimentary and tectonic evolution of the Early Cretaceous rift by drawing eight paleogeographic and geodynamic maps from the Berriasian to the Middle–Late Aptian, based on a biostratigraphic (ostracodes and pollen) chart recalibrated on absolute ages (chemostratigraphy, interstratified volcanics, Re–Os dating of the organic matter).

The central segment of the South Atlantic is composed of two domains, with a two phases evolution of the pre-drift (“rifting”) times: a rift phase characterized by tilted blocks and growth strata, followed by a sag basin. The southern domain includes the Namibe, Santos and Campos Basins. The northern domain extends from the Espirito Santo and North Kwanza Basins, in the south, to the Sergipe–Alagoas and North Gabon Basins to the north.

Extension started in the northern domain during the Late Berriasian (Congo–Camamu Basin to the Sergipe–Alagoas–North Gabon Basins) and migrated southward. At that time, the southern domain was not a subsiding domain (emplacement of the Parana–Etendeka Trapp). Extension started in this southern domain during the Early Barremian. The rift phase is shorter in the south (5–6 Ma, Barremian to base Aptian) than in the north (19 to 20 Myr, Upper Berriasian to base Aptian). The sag phase is of Middle to Late Aptian age. In the northern domain, this transition corresponds to a hiatus of Early to Middle Aptian age.

From the Late Berriasian to base Aptian, the northern domain evolves from a deep lake with lateral highs to a shallower organic-rich one with no more highs. The lake migrates southward in two steps, until the Valanginian at the border between the northern and southern domains, until the Early Barremian, north of Walvis Ridge.
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Chaboureau Anne-Claire, Guillocheau Francois, Robin Cecile, Rohais Sebastien, Moulin Maryline, Aslanian Daniel (2013). Paleogeographic evolution of the central segment of the South Atlantic during Early Cretaceous times: Paleotopographic and geodynamic implications. Tectonophysics, 604, 191-223. Publisher's official version : https://doi.org/10.1016/j.tecto.2012.08.025 , Open Access version : https://archimer.ifremer.fr/doc/00149/26057/