Estudio de los domos del Volcán Quilotoa y su correlación con la estratigrafía del volcán

Abstract

The Quilotoa volcano, has experienced thirteen eruptive cycles in his approximately 200.000 years of geological history. Within it some domes were emplaced, which are located at the edge of the present caldera. Petrographically, the mayority of these domes are porphyritic dacites, which are formed by a typical mineralogical assemblage of plagioclase, hornblende, biotite and quartz. A petrographic comparison allows identifying the presence of eighteen domes at the edge of the volcano´s caldera and, their approximated formation order. The petrographic correlation between the domes and the stratigraphy shows that the domes were formed between (34.000 – 800) aAP, corresponding to the last four eruptive cycles of the volcano (Q-1 to Q-4). The quemical correlation allowed to determinate that all the domes and the samples of the last twelve eruptive cycles of the volcano (Q-1 to QS-12) correspond to dacites; whilst the first eruptive cycle samples of the volcano (QS-13) correspond to riolites. The present work consider correct to the domes formation sequence obtained petrophically, and to its correlation with the thirteen eruptive cycles of Quilotoa volcano, because the alterations have possibly modified the concentrations of the elements that are present in the studied lithologies.