Abstract: Folded-Belts--Petroleum Systems of Northern South America

Felipe Audemard

A series of seismic reflection profiles allow to document the styles, timing and relevant characteristics to the petroleum systems associated with the folded belts along northern South America. These mountain systems are responsible for the partial destruction of the thin Cretaceous Atlantic type passive margin, and as the northern source of sediments for the Tertiary Venezuelan foredeeps.

The passive margin is only preserved at the far-East limit of the Eastern Venezuela Basin, East of the Orinoco Delta. This margin became progressively deformed to the West, where a Neogene segment of a thin-skin south-vergent folded belt is reported as the Eastern Serrania del Interior, which is in turn coupled to the evolution of the Maturin Foredeep. Westwardly, the Late Paleogene-Early Neogene Guarico Foredeep is tied to the emplacement of a basement involved folded belt, the Western Serrania del Interior.

West of the El Baul High, a two stage folded belt is coupled to the Barinas Foredeep. A first phase corresponds to the Eocene south vergent Lara Nappes, and a satellite Foredeep due to the north-vergent emplacement of the basement involved Late Neogene Merida Andes. Farther west, the Apure-Llanos sub-basin is developed from an Early Paleogene basement-involved folded belt, modified to its present configuration by a Neogene reactivation of the east-vergent Eastern Cordillera of Colombia. These folded belts have unique conditions defining the petroleum systems but always had been related to the Late Cretaceous source rocks.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela