The onshore northeast Brazilian rift basins: An early Neocomian aborted rift system

Conference · Tue May 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6666935

Matos, R ^[1]

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1. Cornell Univ., Ithaca, NY (USA)

Early Cretaceous rift basins of northeastern Brazil illustrate key three-dimensional geometries of intracontinental rift systems, controlled mainly by the basement structures. These basins were formed and then abandoned during the early extension associated with the north-south-propagating separation of South America and Africa. During the early Neocomian, extensional deformation jumped from the easternmost basins (group 1: Sergipe Alagoas and Gabon basins; group 2: Reconcavo, Tucano, and Jatoba basins) to the west, forming a series of northeast-trending intracratonic basins (group 3: Araripe, Rio do Peixe, Iguatu, Malhada Vermelha, Lima Campos, and Potiguar basins). The intracratonic basins of groups 2 and 3 consist of asymmetric half-grabens separated by basement highs, transfer faults, and/or accommodation zones. These basins are typically a few tens of kilometers wide and trend northeast-southwest, roughly perpendicular to the main extension direction during the early Neocomian. Preexisting upper crustal weakness zones, like the dominantly northeast-southwest-trending shear zones of the Brazilian orogeny, controlled the development of intracrustal listric normal faults. Internal transverse structures such as transfer faults (Reconcavo basin and onshore Potiguar basin) and accommodation zones (onshore Potiguar basin and Araripe basin) were also controlled by the local basement structural framework. Transverse megafaults and lithostructural associations controlled the three main rift trends. The megashear zones of Pernanbuco (Brazil)-Ngaundere (Africa) apparently behaved like a huge accommodation zone, balancing extensional deformation along the Reconcavo-Jatoba/Sergipe Alagoas-Gabon trends with simultaneous extension along the Araripe-Potiguar trend. The Sergipe Alagoas-Gabon trend and the Potiguar basin represent the site of continued evolution into a marginal open basin following early Neocomian deformation.

• OSTI ID: 6666935
• Report Number(s): CONF-900605--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
BRAZIL
CRETACEOUS PERIOD
DEVELOPING COUNTRIES
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
LATIN AMERICA
MESOZOIC ERA
RIFT ZONES
SEDIMENTARY BASINS
SOUTH AMERICA