Boletín de Geología

Vol. 26 No. 42 (2004): Boletín de Geología
Articles

Chemically sector-zoned garnets in the metapelitic rocks of the Silgará Formation in the central Santander Massif, colombian andes: occurrence and growth history

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  • O. Castellanos,
  • C. Rios,
  • A. Takasu

Published 2004-03-25

Keywords

  • Silgará Formation,
  • Santander Massif,
  • chemically sector-zoned,
  • garnet,
  • metamorphism

How to Cite

Castellanos, O., Rios, C., & Takasu, A. (2004). Chemically sector-zoned garnets in the metapelitic rocks of the Silgará Formation in the central Santander Massif, colombian andes: occurrence and growth history. Boletín De Geología, 26(42), 9–18. Retrieved from https://revistas.uis.edu.co/index.php/revistaboletindegeologia/article/view/906
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Abstract

Almandine-rich garnet in the Silgará Formation metapelitic rocks in the central Santander Massif usually shows concentric normal chemical zoning. However, different types of garnet zoning have been reported, including chemically sector-zoned garnet, which is described here. Recent studies reveal additional discoveries of this type of zoning in different localities. Textural sector-zoned garnets have been observed in the staurolite-kyanite metamorphic zone of the Silgará Formation. They are generally fine-grained (0.25-2.00 mm in diameter), and occur in quartz-rich bands with other textural types of garnet (skeletal and poikiloblastic). The study of the chemically sector-zoned garnet indicates that it has grown in the latest stage of the Silgará Formation metamorphism, during the emplacement of orthogneiss masses. Studies on garnet from the Silgará Formation pelitic rocks have shown the importance of this as a key piece for interpretation of the tectono-metamorphic history of this metamorphic unit.

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