Structural Styles in the Bahia Basin and the South Caribbean Deformed Belt, Colombian Caribbean Margin

Abstract

Abstract

The South Caribbean Deformed Belt (SCDB), a deepwater fold and thrust belt, is located on the southern margin of the Caribbean Plate offshore Colombia and NW Venezuela, and it is considered to be a Neogene accretionary prism which has formed due to the collision and subduction of the Caribbean Plate beneath the South American Plate. Many studies, stimulated by the long history of exploration and production of hydrocarbons, have focused on the understanding of the evolution of the SCDB and the inboard fore-arc and back-arc basins. These studies have identified a complex history of subduction and strain partitioning along northern South America as a result of the relative eastern movement of the Caribbean Plate. Although the overall timing and structural styles of several basins along the area between the SCDB and the Oca-El Pilar Fault System have been previously analysed, the structural styles and basin evolution at the western end of this margin has not been clearly understood and are mostly described at a regional scale. Well data and integrated 2D/3D seismic datasets located in front of the NW corner of the Santa Marta Massif are analysed with the aim of understanding this complex geological setting

The sedimentary section from the shelf to the ocean floor exhibits a wedge shape geometry, which can be divided into two zones with distinct structural styles. SW-NE trending thrusts and folds form the frontal part of the wedge towards the offshore, and high-angle faults with extensional offsets dominate the rear of the wedge, towards the shelf. The frontal structures exhibit a geometry typical of an accretionary prism while the structures towards the rear are deep-rooted and have accommodated significant strike-slip displacement forming a pull-apart basin (Bahia Basin)

The evolution of the Bahia Basin is important for understanding the kinematics of deformation in an oblique subduction setting with the development of transpressional basins at the rear of an accretionary wedge, and corresponds to the westernmost example of strike-slip deformation within the South Caribbean margin. Faults in the Bahia Basin are also of interest for structural geologists because they provide an excellent example of a well-imaged interaction of extensional and strike-slip faults, and the development of an early pull-apart basin style in an oblique compressional setting. These results are key for the development of future E&P-hydrocarbon campaigns in these and similar regions

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016