Exhumation-denudation history of the maracaibo block, Northwestern South America: Insights from thermochronology

Abstract

The Maracaibo block forms a distinct continental fragment in northwestern South America lying between the Oca-El Pilar fault (north) and the Santa Marta-Bucaramanga fault (southwest). Bounding this continental block are the Sierra Nevada de Santa Marta, Perijá, Mérida, and Macizo de Santander mountain belts. These belts were formed by complex geodynamic interactions between the Caribbean Plate, the Panamá Arc, and the South American Plate, which resulted in the reactivation of major preexisting structures or inherited discontinuities. In this study we summarize published40Ar/39Ar, fission-track, and (U-Th)/He data. The data organization takes into account the movement of different plates in time and space, major present-day regional faults, geophysical data, and precipitation patterns permitting the identification of different tectonic blocks with contrasting cooling and exhumation histories. Unraveling the cooling history of the individual blocks leads to an improved understanding of the control of preexisting faults and regional Caribbean geodynamics on the evolution of northwestern South America.