Investigators:	Hans G. Avé Lallemant
Graduate Student:	Jaime Armas Perez	Funding Source:	PRF and Oil Companies

Foreland basin sedimentary rocks in the Valle Morón, State of Guárico, Venezuela.

The Serranía del Interior foreland fold and thrust belt in northeastern Venezuela has been and still is being explored intensively for hydrocarbons. Surprisingly, the geological and particularly the thermal evolution of the area are still not well understood. Most models for the origin of the thrust belt and the metamorphic 'hinterland' in the north suggest that they were formed by transcontraction and highly oblique collision of the Caribbean plate and Lesser and Leeward Antilles volcanic arc with the northern margin of the South American plate. Indeed, it seems that deformation of the South American continental margin has been diachronous: in western Venezuela it started in the Eocene, in north-central Venezuela in the Oligocene, in north-eastern Venezuela (Maturín area) in the Miocene, whereas near Trinidad the collision is occurring today. However, several apatite and zircon fission-track analyses of Cretaceous and Paleogene sedimentary rocks in northern and eastern Venezuela suggest that uplift and exhumation started already in the Eocene before the Lesser / Leeward Antilles volcanic arc obliquely collided with and migrated past the area. More fission-track and structural analyses are needed to constrain the timing of deformation, uplift, and exhumation.