Abstract

OSORIO, Pablo et al. The Villamaría-Termales Monogenetic Volcanic Field, Central Cordillera, colombian Andes (Part II): Compositional characteristics. bol.geol. [online]. 2018, vol.40, n.3, pp.103-123. ISSN 0120-0283.  https://doi.org/10.18273/revbol.v40n3-2018006.

The Villamaría-Termales Monogenetic Volcanic Field (VTMVF) consists of at least 14 monogenetic volcanoes that are aligned along the Villamaria-Termales Fault System (VTFS; western flank of the Central Cordillera of Colombia). Petrography and geochemical data allowed to define the compositional features of this volcanic field. The petrographic analysis shows that: pyroxene + amphibole + plagioclase, is the common mineral association for all the volcanoes from the VTMVF. The presence of other mineral phases such as: olivine and quartz in some volcanoes established the only difference between the whole field. Geochemical data shows a great compositional variety in the VTMVF represented by the SiO2 content between ~56 and ~69 wt.%, and an adakitic signature represented by low Y content (10 - 19 ppm) and HREE values as well as high Sr content (>518 ppm). Comparing these characteristics with those from the polygenetic Nevado del Ruiz Volcanic Complex (NRVC), it is possible to suggest a genetic relationship between both and a likely common magmatic reservoir.

Keywords : Colombian Central Cordillera, volcanic field; monogenetic volcanism; subduction zones; lava domes; adakitic-signature.

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