Tectonic Evolution of Sedimentary Basins Around the Arcuate Southeastern Margin of the Caribbean Plate

Author(s): Tricia Alvarez, Heritage Petroleum Limited (presenter); Paul Mann, University of Houston; Lesli Wood, Colorado School of Mines

The Trinidad region of the southeastern Caribbean presents a unique opportunity to observe phases of deformation which are responsible for complex and superimposed deformation structures along the northern South American margin. These deformational phases have developed progressively around the arcuate, eastward-advancing front of the Caribbean plate. The along-strike, plate boundary transition from subduction to strike-slip is documented by differences in the style and deformation in basins overlying South American basement. We interpret deep-penetration 2-D seismic reflection and well data to map tectono-stratigraphic sequences and constrain timing of basin structures. At the Lesser Antilles subduction margin, the ~300 km wide Barbados Accretionary Prism (BAP) is characterized by approximately parallel, forward-breaking thrusts overlain by semi-isolated piggyback basins. The BAP formed above ~5 km thick subducting Atlantic oceanic crust of Jurassic to Early Cretaceous age. In the oblique collisional and strike-slip zone onshore Trinidad, there is a <100 km wide zone of middle Miocene folding and thrusting cut by later strike-slip deformation. This complex fold-and-thrust-belt includes elevated, anticlinal ranges with intervening synclinal basinal areas. The transition from subduction at the eastern margin of the Caribbean plate, to strike-slip displacement along the southern margin of the Caribbean plate occurs over the northwest–southeast-oriented Galera tear fault zone (GTFZ). The GTFZ is a location of incipient lithospheric tearing—with overlying Neogene transtensional basins—aligned with the boundary between South American continental crust which experienced oblique-collision and translation, and orthogonally subducting South American (Atlantic) oceanic crust.

Bio:

Tricia Alvarez, Heritage Petroleum Company Limited

Tricia earned a BSc from the University of the West Indies, and a MS and a PhD both from the University of Texas at Austin.

With more than 10 years of experience in the industry, she is Geoscience Lead at Heritage Petroleum Company Limited in Santa Flora, Trinidad and Tobago, where she is responsible for providing geoscience expertise in finding exploration and development opportunities with responsibilities for framing and executing geoscience evaluations; developing exploration and development programs; and maintaining portfolio of ranked prospects and drilling opportunities.

She has previously worked as Assistant Professor at The University of Trinidad and Tobago with responsibilities of developing, updating and delivering geoscience curriculum for Petroleum Engineering programs; geoscience research and collaborative studies in Trinidad area basins and petroleum systems; supervising student research and projects. Previously Geologist at BG Trinidad and Tobago Ltd with responsibilities for geologic evaluation including play and prospect analysis, and stratigraphic and depositional systems evaluation within Trinidad and Tobago’s offshore basins. Tricia is a member of AAPG, GSTT, Society for Sedimentary Geology.