Abstract

CASTELLANOS-ALARCON, Oscar Mauricio; RIOS-REYES, Carlos Alberto  and  GARCIA-RAMIREZ, Carlos Alberto. Occurrence of chloritoid-bearing metapelitic rocks and their significance in the metamorphism of the Silgará Formation at the Central Santander Massif. Bol. cienc. tierra [online]. 2016, n.40, pp.5-15. ISSN 0120-3630.  https://doi.org/10.15446/rbct.n40.48416.

We report here for the first time the occurrence of chloritoid in Mg-Al-rich metapelitic rocks of the Silgará Formation at the Central Santander Massif, which was metamorphosed up to the amphibolite facies. These rocks contain an unusual mineral assemblage such as quartz + biotite + muscovite + garnet + staurolite ± kyanite ± chloritoid, with minor plagioclase and K-feldspar, and Fe-Ti oxides as the main accessory phases. Associated carbonate rocks containing the mineral assemblage tremolite + calcite. Chloritoid occurs as porphyroblastic tablets in graphite-bearing metapelitic schists highly tectonized that can be associated to the influence of the major tectonic structures in the study area. The occurrence of chloritoid as an index mineral in metapelitic rocks of the Silgará Formation is attributed to a thermal event (associated to the emplacement of small granitic masses) overimposed on the regional metamorphism.

Keywords : Chloritoid; Metapelitic rocks; Silgará Formation; Central Santander; Massif; Colombian Andes.

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