New Contributions to the Geodynamics of the Caribbean through Structural Transects in the Gulf of Venezuela and its Implications in the Definition of Petroleum Systems

Malavé, Bladimir J.¹ and Contreras, Omar J.
¹[email protected]

A structural interpretation in the Gulf of Venezuela has been developed using 2D seismic data and stratigraphic information from wells located into the gulf and surrounding basins. The scope of this survey was focused on describing the structural evidences associated with different stages of tectonic deformation that occurred in the Gulf. To carry out this work, the tectonic evolution of the zone has been divided in four chronologic stages: 1) the Proto-Caribe aperture and the Gondwana-Laurasia separation; 2) thermal subsidence of the Proto-Caribe below the south America plate and development of passive margin at the north of South America; 3) Caribbean-South America collision and emplacement of Caribbean crust over the continental margin; and 4) development of the right-lateral fault system as a response of the oblique Caribbean-South America collision.

As a result, two geologically differentiable domains were observed in the seismic interpretation: Urumaco Trough and Guajira-Dabajuro Domain. Urumaco Trough Domain is characterized by a thick Neogene Sedimentary sequence filling lying unconformably over an Allochtonous Metamorphosed Basement. This sequence was deposited into a tectonic transtensive regimen associated with the rigth-lateral desplacement of the Oca-Ancon fault system and the aperture of a Pull-Apart basin. The deposition was controled by the development of the NW-SE Miocene-Pleistocene normal faults, with sediments probably sourced from the south. In case of Guajira-Dabajuro Shelf domain, the Neogene sequence is recognized as a thinner continuity of the Neogene sequence in Urumaco Trough and this is overlapping unconformably to the Jurassic-Cretacic sequence correlatable with the Maracaibo Lake domain

In this domain, another significance result, related to the structural features, was found. Fault-Bend-Folds structures with ramps verging North-West involving Jurassic to Paleocene Sequences were identified. These structures form a thrust-belt in the NE-SW direction, as a result of the NW-SE compressive events which might be associated to the Caribbean-South America oblique collision that started since late cretaceous. By the way, a lower exploration risk in the Guajira-Dabajuro domain is assumed because of the repetition of the Cretaceous-Paleocene sequence, the development of the traps associated with this structural style of deformation, and the presence of the cretaceous sequence deposited in the continental passive margin.

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013