Tectono-magmatic analysis of the Juanambú Canyon, Southwestern Colombian Andes

This contribution integrates petrological and field relation constrains from the geological record of the Juanambú River Canyon and provides another important record of the Late Cretaceous to Miocene tectono-magmatic evolution of the southwestern margin of the Colombian Andes. Furthermore, the first 1:25.000 geological cartographic chart is presented within this project and it could be enhanced and used as a basis for the territorial planning, the evaluation of natural resources and the recognition of geological risks. Two intrusive bodies were recognized in the study area: First, a Late Oligocene to Early Miocene phaneritic-tonalitic rock body mainly composed by plagioclase with complex zonation, variable quantities of mafic minerals and lesser amounts of quartz. Second, a Middle to Late Miocene porphyritic intermediate to acid rock intruding the tonalitic bodies and mainly constituted by plagioclase and quartz, and in lesser amounts hydrated amphibole and biotite filling interstitial spaces. Granitoids are characterized by high contents of silica SiO_2 (66-70 wt.%), with a metaluminous to slightly peraluminous composition (ASI= 0.96-1.03). The analyzed samples exhibit a calc-alkaline character and show an intermediate to acid composition, ranging from granodiorites to granites. Tectonic classification diagrams also suggest a volcanic arc affinity related to a subduction tectonic setting. Eastward migration of the magmatic arc has been suggested for northern and central segments of the Colombian Andes, nevertheless, in the southern Juanambú Canyon region the longitudinal displacement of magmatism is not recognized. The observed spatial framework in the canyon could be related to a late migration of the magmatism over a stationed axis for southern parts of the Colombian Andes or to a subduction edge with convex center and concave extremes geometrical configuration which induced a less prominent slab dip to the southern segment represented by this region

• Autores: Delgado Balaguera, Sofía Margarita
• Tipo de recurso: Trabajo de grado de pregrado
• Fecha de publicación: 2018
• Institución: Universidad de los Andes
• Repositorio: Séneca: repositorio Uniandes
• Idioma: eng
• OAI Identifier: oai:repositorio.uniandes.edu.co:1992/40432
• Acceso en línea: http://hdl.handle.net/1992/40432
• Palabra clave: Geología; Geociencias
• Rights: openAccess
• License: http://creativecommons.org/licenses/by-nc-sa/4.0/