Abstract

RIOS R, Carlos Alberto  and  CASTELLANOS A, Oscar Mauricio. Petrologic significance of Fe-rich staurolite in pelitic schists of the Silgará Formation, Santander Massif. Earth Sci. Res. J. [online]. 2016, vol.20, n.1, pp.1-7. ISSN 1794-6190.  https://doi.org/10.15446/esrj.v20n1.40847.

Medium grade metapelites of the Silgará Formation at the Santander Massif (Colombian Andes) have been affected by a medium-pressure/high-temperature Barrovian type of metamorphism, developing a sequence of metamorphic zones (biotite, garnet, staurolite and sillimanite). These rocks record a complex tectono-metamorphic evolution and reaction history. Metapelitic rocks from the staurolite zone are typically foliated, medium- to coarse-grained, pelitic to semipelitic schists that contain the mineral assemblage biotite + garnet + staurolite ± kyanite; all contain muscovite + quartz + plagioclase with minor K-feldspar, tourmaline, apatite, zircon, epidote, calcite, and Fe-Ti oxides. Field and microscopic evidences reveal that Fe-rich staurolite in pelitic schists is involved in several chemical reactions, which explains its formation and transformation to other minerals, which are very important to elucidate the reaction history of the Silgará Formation metapelites.

Keywords : Staurolite; pelitic schists; Silgará Formation; metamorphism; Santander Massif.

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