Volcanism of the La Quinta Formation in the Perijá mountain range

Abstract

This study reports new data on the petrography, total rock chemistry and U-Pb zircon geochronology of volcanic rocks of the La Quinta Formation that outcrop the western flank of the Perijá mountain range and the Cesar and La Guajira departments. The volcanic rocks consist of basaltic, andesitic, dacitic and rhyolitic lavas, and the volcaniclastic rocks consist of crystal-vitric and crystal-lithic tuffs and agglomerates of calc-alkaline affinity, formed in a continental margin arc setting. Geochronological data suggest that the La Quinta Formation was volcanically active for approximately 25 Ma, during which its composition varied from basaltic trachyandesites to rhyolites. U-Pb dating suggests that the volcanism began in approximately 191 Ma (Sinemurian age) and continued until approximately 164 Ma, with at least three periods of increased volcanic activity. The inherited zircons contain Triassic, Permian, Neoproterozoic and Mesoproterozoic populations, indicating that this arc was emplaced on rocks of the Chibcha Terrane along the South American paleomargin and that it is part of the same arc that formed the Jurassic volcanic rocks of the Sierra Nevada de Santa Marta, Cocinas and San Lucas mountain ranges and the Upper Magdalena Valley.