Chapter 8 - Relationships between normal faulting, mud diapirism and thrusting in the trailing part of the Sinú Fold Belt (South Caribbean Deformed Belt), offshore Northwestern Colombia

Abstract

The Sinú Fold Belt, located in northwest offshore Colombia, is the frontal part of the southwestern portion of an accretionary wedge, known as the South Caribbean Deformed Belt, which resulted from the subduction of the Caribbean Plate under the South American Plate. The leading part of the Sinú Fold Belt, the continental slope, is dominated by thrusts and related folds, while in the trailing part of the fold belt, the continental shelf, these structures coexist with large normal faults and mud diapirs. The detailed geological interpretation of a seismic line in time across the continental shelf shows that, during Pliocene and Quaternary, normal faults, mud diapirs, and thrusts developed discontinuously in time and space, alternating between periods of intense tectonic activity, and periods of relative tectonic quiescence. Some normal faults were reactivated more than once as normal or reverse faults, and some of them became toe thrusts toward their tectonic transport sense. The mud diapirs piercing rollover anticlines, thrust-ramp folds, and different parts of the fault hanging walls may reach the seafloor or remain buried.