Structural framework, stratigraphy, and evolution of Brazilian marginal basins

Journal Article · Tue Jun 01 00:00:00 EDT 1982 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6622109

Ojeda, H A.O.

The structural framework of the Brazilian continental margin is basically composed of eight structural types: antithetic tilted step-fault blocks, synthetic untilted step-fault blocks, structural inversion axes, hinges with compensation grabens, homoclinal structures, growth faults with rollovers, diapirs, and igneous structures. The antithetic tilted and synthetic untilted step-fault blocks are considered as synchronous, complementary structural systems, separated by an inversion axis. Two evaporitic cycles (Paripueira and Ibura) were differentiated in the Sergipe-Alagoas type basin and tentatively correlated to the evaporitic section of other Brazilian marginal basis. Four phases are considered in the evolution of the Brazilian marginal basins: pre-rift, rift, transitional, and drift. During the pre-rift phase (Late Jurassic-Early Cretaceous), continental sediments were deposited in peripheral intracratonic basins. In the rift phase (Early Cretaceous), the breakup of the continental crust of the Gondwana continent gave rise to a central graben and rift valleys where lacustrine sediments were deposited. The transitional phase (Aptian) developed under relative tectonic stability, when evaporitic and clastic lacustrine sequences were being deposited. In the drift phase (Albian to Holocene), a regionl homoclinal structure developed, consisting of two distinct sedimentary sequences, a lower clastic-carbonate and an upper clastic. From the Albian to the Holocene Epoch, structures associated to plastic displacement of salt or shale developed in many Brazilian marginal basins. Two phases of major igneous activity occurred: one in the Early Cretaceous associated with the rift phase of the Gondwana continent, and the other in the Tertiary during the migration phase of the South American and African plates.

• Research Organization: Petroleo Brasilerio S.A., Rio de Janeiro
• OSTI ID: 6622109
• Journal Information: Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 66:6
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
58 GEOSCIENCES
BRAZIL
PETROLEUM DEPOSITS
STRATIGRAPHY
TECTONICS
CONTINENTAL MARGIN
CRETACEOUS PERIOD
EVAPORITES
GEOLOGIC FAULTS
TERTIARY PERIOD
CENOZOIC ERA
DEVELOPING COUNTRIES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
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LATIN AMERICA
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MINERAL RESOURCES
RESOURCES
ROCKS
SEDIMENTARY ROCKS
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