New data on evolutive trends of Third Magmatic Cycle (Post-Roque Nublo Group) volcanism in Gran Canaria (canary Islands, Spain)

Abstract

This note exposes preliminary data (petrography, TAS classification) obtained from a 44-samples study of lavas corresponding to the Third Magmatic Cycle of Gran Canaria island. These samples has been chosen from a 120 studied set, taking into account good preservation and specific geologic situation in order to obtain a new K/Ar systematic geochronology of recent volcanic rocks of the island. We can remark a good agreement with published available results (including older ones); in despite of this, the simultaneous knowledge of correct ages allows new interpretations of the recent geologic history of Gran Canaria island. The most prominent new evidence is that evolved rocks corresponding to the end of Roque Nublo Cycle are coeval during a relatively broad span of time (3.6-2.9 Maj with the pristine (basanitic) terms of rift volcanism (initial volcanism of Third Magmatic Cycle).