Abstract

VALENCIA-MORALES, Yuly Tatiana; TORO TORO, Luz Mary; RUIZ-JIMENEZ, Elvira Cristina  and  MORENO-SANCHEZ, Mario. Pressure-Temperature path of Arquía Group rocks (NW Colombia): a petrographic analysis from mineral assemblages. Earth Sci. Res. J. [online]. 2013, vol.17, n.2, pp.141-149. ISSN 1794-6190.

Based on the type locality mineral associations of the Arquía Group metamorphic rocks in Colombia, the pressure-temperature conditions of metamorphism were obtained and the associated P-T path was built. The analysis of the mineral assemblages indicates a prograde regional metamorphism, which varies from low to medium grade and is represented by greenschist, epidote-amphibolite and amphibolite facies. The results that are based on the prograde mineralogy [actinolite + chlorite + albite + quartz + muscovite + epidote minerals for greenschist facies and hornblende + epidote minerals + garnet + albite ± quartz for epidote-amphibolite and amphibolite facies] indicate a constant increase of metamorphic conditions from 433°C/11.8 kbar to 696°C/14.4 kbar in the metamorphic peak. Retrograde mineral assemblages [muscovite + chlorite + epidote minerals + albite + actinolite] indicate new metamorphic conditions between 417-357°C and 8.1-6.5 kbar. In addition, four deformation events and evidence of shear zone and intracrystalline deformation were found in these rocks.

Keywords : Arquía Complex; Arquía Group; mineral assemblages; metamorphism; P-T path.

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