Geomorphologic evidences of flank instabilities in the eastern sector of the tejeda volcano (Canary Islands, Spain) during the quaternary

Abstract

This paper provides both geological and geomorphologic observations that support the existence of flank instabilities in the eastern sector of the Tejeda Volcano (Gran Canaria) during the Quaternary. The observations are focused on the analysis of the drainage system, scarps, erosion surfaces, residual reliefs, field of volcanoes and lithological correlation between the surface geology and data derived from wells and boreholes. We have identified a wide paleo-valley developed in Miocene volcanic materials, which could be related to a large rock slide, as well as a subsequent secondary scarp of Pliocene age developed at the distal area of the slide mass. These observations confirm the occurrence of large insular flank collapses of the Tejeda Volcano during the Miocene to Pliocene. These flank instabilities suggest a NE-SW extensional regime, which could be related to a NW-SE fault zone that divides Gran Canaria Island into two sectors.