Cariaco

Venezuela Offshore

Falcon Offshore

This tectonic sketch is a tentative representation of the global geological setting of the South America lithospheric plate, in which two main subduction zones are clearly visible, which bound the Meso-Cenozoic megasuture. The northern subduction zone is a B-Type subduction (Benioff type), in which the descending plate is oceanic. B-type subductions are highlighted by an: (i) Oceanic trench ; (ii) Alignment of volcanoes and (iii) Deformation in the overriding plate, which often causes the formation of mountains. The southern subduction zone is A-type subduction zone (Ampferer type), in which the descending plate is continental. A-type subduction are characterized by a foreland basin (foredeep). The area of interest (Falcon offshore), located near the Gulf of Venezuela (Falcon geographic basin) lies within the Meso-Cenozoic megasuture. The episutural basin sediments sediments are, highly, shortened and the presence of major shear zones , creates, mainly, two types of sedimentary basins : (i) "Great Basin" Type and (ii) California-Type. The "Great Basin"-Type Basins are dominated by a complex tectonics linked to a pair of mega-shears where tilted blocks individualize a large number of small basins (e.g., Vela and Falcon geographic basins). This tilting geometry contrasts with that of Californian-type basins which are most often uniform and very flat. The Californian-type basins are similar to the continental backarc basins of Pannonian-type. Both develop over a thinned continental crust in association with normal listric faults or shears, having a strong thermal flux. In Venezuela, the Gulf of Paria, Falcon geographic basins and the Cariaco geographic basin are good examples of California-type basins as illustrated below

This tentative geological interpretation is quite typical of an episutural California-type basin, in which, as illustrated, the movement of major shear complex zones seem, partially, control not only the sedimentary accommodation (space available for the sediments), but the sedimentary deformation as well. The proposed seismo-stratigraphy, which follows the stratigraphic signature proposed by P. Vail and coauthors, was controlled by the results of exploration wells drilled by PDVSA.