--> Shear Fault-Bend Folding Across the Southern Caribbean Basin, Offshore Northern Colombia — Implications for Hydrocarbons Exploration

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Shear Fault-Bend Folding Across the Southern Caribbean Basin, Offshore Northern Colombia — Implications for Hydrocarbons Exploration

Abstract

Abstract

The South Caribbean basin represents an accretionary prism that resulted from the transpressional collision between the Caribbean and South American plates during the Tertiary. An imbricate thrust system in the southern portion of the basin is clearly imaged with 2-D seismic reflection data, which was used to interpret fold and fault geometries and patterns of growth sedimentation. This imbricate system was modelled using a combination of conventional and shear imbricate fault-related folding theories. The patterns of growth sedimentation that can be observed in this imbricate system are used to further constrain the models. Shear fault-bend folding is the dominant kinematic mechanism of deformation in the imbricate system of the Southern Caribbean Basin, offshore northern Colombia. Several characteristics allow the interpretation of shear imbrication in this system including: A) beds on the backlimbs of individual fault-related folds that dip less than the associated fault ramps, B) growth sediments show evidences of both limb rotation and kink-band migration, and C) decreasing bed dips, gravitational collapse and mud diapirism landward. The imbricate systems of the Southern Caribbean basin were active early during the Miocene-Pliocene with thrust faults emerging in the sea floor. Further foreland imbrication has shear this system and passively transported it forward along an Oligocene(?) basal detachment during the Pliocene to the Present time. This kinematic model of deformation has important implications for the regional shortening of this fold and thrust belt, sequences of imbrication, regional distribution of syn-tectonic reservoirs, and ongoing extensional collapse and shale diapirism. This kinematic model of deformation is also important for the exploration assessment of this basin, and needs to be considered when developing new prospects in this type of frontier basins.