Rifting and early tectonic evolution of the equatorial Atlantic
The Equatorial Atlantic forms a giant transform connecting the Central and the South Atlantic between northwest Africa and Brazil. Improved onshore mapping and offshore seismic and drilling by Petrobras permitted the differentiation of the following phases in the tectonic evolution of the Equatorial Atlantic: (1) Basaltic volcanism along the eastern and southern margins of the Guyanan Shield during Triassic-Jurassic time as North America separated from Gondwana. (2) During Early Cretaceous time, clockwise rotation of South America caused rifting east of Fortaleza and compression and arching of the basement further west. Subsequently, the rift propagated westward along the whole length of the Equatorial Atlantic. (3) From Albian time on, there has been right-lateral divergent movement between northwest Africa and South America. (4) This movement was interrupted by intense compression in the Late Cretaceous resulting from convergence between southwest Europe and Africa, causing shortening and southward thrusting of the rift sequence. This compression was alleviated by left-lateral movement along the intracontinental Sobral transform.
- Research Organization:
- Petrobras Research Center, Rio de Janiero (Brazil)
- OSTI ID:
- 6273684
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
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