--> Characterization of the São Tomé Cape Transfer Zone - Campos Basin - RJ – Brazil, Theodoro, Raquel; Destro, Nivaldo, #90100 (2009)

Datapages, Inc.Print this page

Characterization of the São Tomé Cape Transfer Zone - Campos Basin - RJ – Brazil

Theodoro, Raquel1
 Destro, Nivaldo2

1ABIG, Petrobras, Macaé, Brazil.
2
CENPES, Petrobras,
Rio de Janeiro, Brazil.

The rift phase of the
Campos Basin is marked by NE-SW-trending normal faults, which are controlled by pre-existent Precambrian weak zones. The São Tomé Cape Transfer Zone was identified by gravimetric and hydrogeologic maps, and is an overlapping transfer zone situated between the São João Graben, located mostly offshore of the Campos Basin, and the Campos Graben, located onshore in this basin; both grabens are oriented in the NE-SW direction. The main fault of the Campos Graben, named São João da Barra Fault dips towards SE and presents maximum vertical displacement of 1.380 m. A WNW-ESE-trending release fault located in its hangingwall block presents an intermediate displacement of 460 m. A NW-SE-trending graben oriented transversally to the rift axis, cuts across the São Tomé Cape Transfer Zone and connects the São João and Campos grabens. One of its NW-SE-trending faults presents a flower structure and significant lateral lithologic difference, indicating components of strike-slip movements on some of these faults. This may be due to later crustal pull-apart movements and pole rotation, which reactivated NW-SE-trending normal faults as strike-slip faults. This NW-SE-trending graben compartmentalizes the onshore portion of Campos Basin in two distinct structural domains, which were interpreted as compressional towards SW, and extensional towards NE, of the São Tomé Cape Transfer Zone. NW-SE-trending faults are also common in the compartmentalization of other areas of the Campos basin. The compressional and extensional domains are related to the orientation of the strike-slip faults with respect to the plate-driven stresses, which allows characterizing regions with transpressional or transtensional styles. Another WNW-ESE-trending fault that shows a flower structure was interpreted as the result of the E-W-splitting between the South American and African continents. The studied data indicate that several events were superposed to the São Tomé Cape Transfer Zone. The tectonic evolutionary model of the Campos Basin can be correlated to the one named Bivergent Lithosferic Extension, which predicts mechanical subsidence, pull-apart basin, lithosferic extension, transitional phase and thermal subsidence. The integration of several data sources corroborates the correlation of the structures in the São Tomé Cape to a complex evolutionary system, of wide geochronological distribution in several extensional stages.

AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil