--> ABSTRACT: Pato-Onado Area Structural Style Venezuelan Eastern Basin, by I. R. Gruber and H. J. Sanchez; #91021 (2010)

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Pato-Onado Area Structural Style Venezuelan Eastern Basin

GRUBER, IRAIMA R., and HUMBERTO JOSE SANCHEZ

The Pato-Onado Area comprises a belt limited by the Anaco thrust fault and the Norte de Monagas deformation front.

The delineation of structural styles that dominate the fault patterns is determinant for the location of oil-bearing sands.

At the begining of the basin development there existed a Cretaceous-Paleocene passive margin. During this period the sedimentary column was exposed by tilting of the basin to the north, and over this eroded surface, the transgressive sands of the Oligocene Merecure formation were deposited. During the upper Oligocene- mid-Miocene period, tectonic elements typical of passive margins were developed, including east-west oriented normal faults dipping south. During this period the transgressive lower and middle section of the Oficina Formation was deposited from the north. The presence of normal faults dipping north are associated with the foreland-type Maturin sub-basin, and were generated by the transcollision of the Caribbean plate with the South American plate during Mid-Miocene. In late Miocene, the compressive activity to the north caused the reactivation of the normal faults, although not enough to cause inversion of the blocks, only folding. At the same time the Freites formation was deposited. During the Pliocene-Pleistocene period, erosion of the compressive province to the north supplied the clastics of the Las Piedras and Mesa formations, which represent the final basin fill, where a compressive regime is still acting. 

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.