Structural evolution of the San Jacinto fold belt, NW Colombia

Abstract

The tectonic evolution of the San Jacinto fold belt comprises an extensional and several compressional events that affected the continental margin of northwestern South America during the Cenozoic: extension with rift or graben infill from Late Cretaceous to Early Eocene, a Middle Eocene inversion, Late Eocene uplift, a relatively quiet period during the Oligocene, Middle Miocene deformation and a Pliocene - Pleistocene period of folding and faulting. This evolution is related to the development of the Caribbean plate and its interaction with the Cocos, Nazca and South American plates. Inversion and reactivation were mostly controlled by the orientation of the pre-existing normal fault planes. These deformational episodes are recorded by several unconformities (Lower Eocene, Middle Eocene, Upper Eocene, Lower Oligocene, Middle Miocene and Upper Pliocene). Structurally, the San Jacinto fold belt is composed of a series of northeasterly trending folds, reverse and normal faults. Restoration of two seismic lines corroborates the proposed model.