Resumo

CABALLERO, Víctor; PARRA, Mauricio  e  MORA BOHORQUEZ, Andrés Roberto. LATE EOCENE - EARLY OLIGOCENE INITIAL UPLIFT OF THE ORIENTAL CORDILLERA OF COLOMBIA: SEDIMENTARY PROVENANCE ON THE NUEVO MUNDO SINCLINE, MIDDLE MAGDALENA BASIN. bol.geol. [online]. 2010, vol.32, n.1, pp.45-77. ISSN 0120-0283.

Associated to the Colombian Andes uplift, the present day Middle Magdalena Valley Basin resulted from the fragmentation of an ancestral foreland basin associated first to the Central Cordillera and then to the uplift by tectonic inversion of the Oriental Cordillera. To constrain the initial uplift of the Oriental Cordillera a study of paleocurrent directions, sediment provenance and facies distribution on the Cenozoic units of the E part of the Middle Magdalena Valley Basin was conducted. A drastic change in the paleocurrent directions was founded from N NE and E SE in the La Paz and Esmeraldas formations (late Eocene), toward W NW in the Mugrosa Formation (early Oligocene), which maintains in the overlying Neogene units. Petrography data indicates at least two sediment source areas, one contributing to the La Paz and Esmeraldas Formations, the other to the Mugrosa and Colorado Formations and both supplied sediment to the Real Formation. The analysis of all this outcrop data and information let us to propose an initial uplift of the Oriental Cordillera since the late Eocene to early Oligocene. From this finding we can infer deformation and oil trap configuration until at least the Eocene time in the Colombia Middle Magdalena Basin.

Palavras-chave : Basin analysis; Paleocurrent analysis; Facies distribution; Sediment provenance; Oriental Cordillera; Central Cordillera; Colombia; Clast counting; Middle Magdalena Valley.

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