Abstract

VALLEJO HINCAPIE, Diego Felipe; SALAZAR RIOS, Andrés Felipe  and  TORO TORO, Luz Mary. PETROLOGY AND GEOCHEMISTRY OF THE INTRUSIVE ROCKS OUT CROPPING BETWEEN MISTRATÓ AND BELÉN DE UMBRÍA TOWNS, (RISARALDA DEPARTEMENT, WEST CORDILLERA COLOMBIANA). bol.geol. [online]. 2011, vol.33, n.2, pp.46-47. ISSN 0120-0283.

The intrusive rocks studied are located between Mistrató and Belén de Umbría towns, Risaralda department, on the eastern flank of the Western Cordillera, at the west of Cauca-Almaguer Faults System. The north of area is dominant by Microgabbros and Gabbros compound of plagioclase (labradorite), ortopiroxene, clinopiroxene ± hornblende. The geochemistry diagrams show low values in potassium, of the tholeitic serie and affinity oceanic. The gabbroic unit has been related with the oceanic terrane of the Western Cordillera. At the south, the outcrops are of acid rocks that go from Quartzdiorite to Granodiorite with higher presence of tonalite. The mineralogy consists of plagioclase (andesine) ± hornblende ± biotite ± alkali feldspar; to the southeast this body is in an intrusive contact with Gabro de Anserma generating a thin contact aureole, and the west presents a wide zone of mylonitic rocks associated with the Mistrató Fault. The Geochemistry results confirm a calco-alkali character, produced in a setting volcanic-arc during the Paleogene.

Keywords : Western Cordillera; Geochemistry; Tholeitic; Calcoalkali; Mistrató Fault.

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