Thermal modeling of pluton emplacement and associated contact metamorphism:parashi stock emplacement in the serranía de jarara (alta guajira, colombia)

Abstract

In the northernmost portion of the Serrania de Jarara (Alta Guajira, Colombia), low - medium grade metamorphic rocks from the Etpana Metamorphic Suite were thermally affected by emplacement of a small calc-alkaline intrusion (Parashi Stock). Detailed petrographic analysis in collected rock samples across the NE and NW plutonic contacts show occurrences of textural and mineralogical changes in the country rock fabric that evidence contact metamorphism overprinting regional metamorphism of the Etpana Suite. These changes include growth of andalusite (chiastolite), calcic clinopyroxeneand amphibole porphyroblast crosscutting Sn+1 metamorphicfoliation. Hornblende-plagioclase barometry (ca. 3.1 kbar) and cooling models for the stock show maximum time temperature evolution in the country rock at the interpreted depth of intrusion (ca. 11 km) and help to evaluate the behavior of the country rock with the changing local geotherm.