Basin formation along the Bocono‐Moron‐El Pilar Fault System, Venezuela

Abstract

Within the boundary zone between the Caribbean‐South America plates, which includes the Boconó‐Morón‐El Pilar right‐lateral fault system that has been active since the late Tertiary, there are several sedimentary basins in the Venezuelan Andes and the Caribbean Mountains. These were formed in zones of crustal depression, where faults diverge, and as pull‐apart basins in zones of en echelon stepovers (or along releasing bends) in the faults. In addition, there are pull‐apart basins along the Avila and La Victoria faultzones in the Caribbean Mountains, which are associated with the plate boundary. The basins are filled with alluvial, lacustrine, fluvial, and marine sediments, mainly of Quaternary age. On the basis of model studies, dimensions of the basins, and age of their sedimentary fill, it is estimated that right‐lateral offset necessary to form them along the Boconó‐Morón‐El Pilar fault system varies from 2 to 125 km. Along the Avila and La Victoria fault zones, this right‐lateral offset is estimated to range from 2 to 30 km. On this basis, the maximum right‐lateral offset along the southern Caribbean plate boundary that can be documented along the Boconó‐Morón‐El Pilar fault system has not exceeded 100–125 km. If there has been larger offset, it has to be documented by other means, or it has taken place along other fault zones within the system.