Produção Nacional
MECANISMO DE RIFTEAMENTO DA PORÇÃO ORIENTAL DA MARGEM NORTE BRASILEIRA
1987; Sociedade Brasileira de Geologia; Volume: 17; Issue: 2 Linguagem: Inglês
10.25249/0375-7536.1987196207
ISSN2177-4382
AutoresJOÃO BATISTA DE LELLIS FRANÇOLIN, Péter Szatmári,
Tópico(s)Geological and Geochemical Analysis
ResumoDuring early Cretaceous, pre-Alagoas time (144-119 Ma), the South Atlantic rift system opened up by clockwise rotation of South América relative to Africa about a poLe located at 7°S and 39°W. This rotation created a unique stress field in and around the present Potiguar Basin in NE Brazil. It is characterized by E-W compression as the rotating tip of South America was pressed against the Cameroon margin in the east, and N-S extension while the continent was pulled away from the Nigerian margin in the north. This stress field reactivated the numerous Precambrian ductile. Shear zones of the area by ruptile transcurrent faulting: right lateral strikeslip along the NE trending Portalegre-Carnaubais Fault and left lateral strikeslip along the E-W trending Patos fault. Imperfect fit between the laterally dislocated, rotated blocks created fault bounded half grabens. The largest one is the oil-bearing Pendência graben of the Potiguar Basin. It formed along the northeastern transtensional segment of the Portalegre-Carnaubais Fault; its southern portion displays broad folds in the early Cretaceous sequence. South of the graben, an E-W trending dike swarm, 126 millions years old, lies along the axis of greatest compression separating the transtensional and transpressional segments of the Portalegre-Carnaubais fault.
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