Caracterización geológica y petrográfica de la avalancha de escombros holocénica asociada al volcán porotog (cerro minas), ubicado en la parroquia de Cangahua, cantón Cayambe, provincia de Pichincha.

Abstract

After field visits, observation, and analysis of outcrops, it was concluded that the deposit is a debris flow, for this reason, the analyses carried out were based on this first premise. The objective of this project is to characterize the geological and petrographic aspects of the debris flow of Porotog Volcano, in addition to confirming or ruling out the presence of hydrothermal alteration in the source, clasts, and matrix of the debris flow. Three different methodologies were employed: First, description of outcrops and rocks, complemented with thin sections, second, granulometric analysis by sieving, and third, use of TerraSpec. The data obtained from the methodology were analyzed using three software packages. First, for the granulometry, the SFT software was used, which allows obtaining statistical values of each sample to be plotted in the Pierson & Scott (1999) diagram. Secondly, to identify alteration minerals, the Specmin software was used, which permits comparing the spectrum taken with the TerraSpec with the spectral library of the software and ArcMap in which the area and volume of the debris flow was delimited and calculated. It was concluded that the debris flow is of a Hiperconcentrated type with an area of 34.61 km² and an approximate volume of 0.0435 km³. In addition, the presence of hydrothermal alteration was confirmed, and two fundamental observations were proposed: the first, hydrothermal alteration is due to the presence of a copper porphyry system and second, Porotog is not a volcano, and its morphology is due to glacial erosion.