Initiation of transform continental margins: the Cretaceous margins of the Demerara plateau

Type Article
Date 2022
Language English
Author(s) Basile ChristopheORCID1, Loncke Lies2, Roest WalterORCID3, Graindorge David4, Klingelhoefer FraukeORCID3, Museur Thomas3, 4, Heuret ArnaudORCID5, Lesourd-Laux Thomas1, 6, Vetel William6
Affiliation(s) 1 : Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, Univ. Gustave Eiffel, ISTerre, 38000 Grenoble, France
2 : University of Perpignan Via Domitia, Centre de Formation et de Recherche sur les Environnements Méditerranéens (CEFREM), UMR 5110, 52 Avenue Paul Alduy, 66100, Perpignan, France
3 : Ifremer, Centre de Brest, Institut Carnot – Ifremer EDROME, UR Géosciences Marines, BP 70, 29280 Plouzané, France
4 : University of Brest, CNRS, IUEM, Plouzané, France
5 : Université de Guyane, UMR 5243 Géosciences Montpellier, Campus de Troubiran, 97300 Cayenne, Guyane, France
6 : Total SA, Centre Scientifique et Technique Jean Feger (CSTJF), Avenue Larribau, 64018, Pau, France
Source Geological Society, London, Special Publications (0305-8719) (Geological Society of London), 2022 , Vol. 524 , N. 1 , P. ??
DOI 10.1144/SP524-2021-118

During the end of the lower Cretaceous, the connection between the South and the Central Atlantic accretionary axis led to the oblique opening of the Equatorial Atlantic, and to the separation of Africa and South America by alternating transform and rift margins. At the western end of the Equatorial Atlantic, we investigate the structure of the Cretaceous margins surrounding the Demerara plateau, north of French Guiana and Suriname. These margins were previously described as transform northward and divergent eastward. From the bathymetry and deep structures, we propose to divide the northern transform into three margin segments, with two transform segments separated by a divergent one. These two transform margins are very different, the north-western one being linear and associated with a steep and erosive continental slope, the north-eastern one consisting of several faults and ridges en echelon disposed. In between, the divergent margin appear to be a pull-apart basin localised by structures inherited from the previous Jurassic rifting. Additionally, the eastern divergent margin can have been localised by a thermal anomaly tentatively related to a hotspot. It is proposed that the deformation has been first localised in divergent (rift) basins, subsequently connected by transform faults. The structure of the transform fault varies with the offset between adjacent rift basins: large offset forms a linear transform, short (less than 200 km) offset forms en echelon structures.

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Basile Christophe, Loncke Lies, Roest Walter, Graindorge David, Klingelhoefer Frauke, Museur Thomas, Heuret Arnaud, Lesourd-Laux Thomas, Vetel William (2022). Initiation of transform continental margins: the Cretaceous margins of the Demerara plateau. Geological Society, London, Special Publications, 524(1), ?? Publisher's official version : , Open Access version :