Raúl Ysaccis¹, Felipe Audemard¹
(1) PDVSA Exploración y Producción, Caracas, Venezuela

Abstract: A Neogene Orogenic Float in Northern South America: Eastern Venezuela Basin Vs Caribbean Plate

A 400-km depth converted seismic profile along one of the most prolific petroliferous province of the world illustrates the Neogene orogenic float defined by the interactions between the Caribbean and South American plates. This 350-km megasuture is confined to two folded belts: The offshore Blanquilla Folded Belt to the north evolving over the oceanic crust and the Serrania del Interior Folded Belt to the south deforming the foreland and passive margin sediments from the Eastern Venezuela Basin.

In the northern central segment of the profile, the relics of the metamorphics and volcanics associated with the Lesser Antilles arc are located in the Margarita - Los Testigos High. In the Araya-Paria Peninsula, at the center, there is an overthrusted metasedimentary belt which corresponds to the frontal deepest portion of the Jurassic-Cretaceous tethyan passive margin edifice and a 100-km wide Tertiary-Cretaceous sedimentary unit crops out to the south in the Serrania del Interior folded belt.

These internal units underwent sizeable adjustments by transpressions and transtensions throughout the evolution of this orogen. These phases have been well documented by exploratory drillings.

A first extension is reported in the Carúpano and Blanquilla basins during the Eocene where over 10000 feet of sediments were deposited. During the Oligocene, tectonic inversion occurred in Carúpano while the Guarico foredeep evolved. The subsequent Miocene inversion in the Blanquilla was coeval with the Maturín foredeep. In the easternmost Serrania and southern Carúpano, much of the earlier Tertiary compressional structures were overprinted by Late Neogene transtension.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana