Imaging the Volcanic Structures Beneath Gran Canaria Island Using New Gravity Data

Abstract

AbstractFrom a new gravity data set that covers homogeneously the whole surface of Gran Canaria (Canary Islands, Spain) and marine gravity data in the nearest offshore, we have obtained a Bouguer anomaly gravity map of the island which improves the previous ones. Using these gravity anomalies, we have applied a gravity inversion approach to investigate the structures beneath the surface of Gran Canaria Island and derive a 3D gravity sources model. The geometry of structures with anomalous density values is constrained up to a depth of approximately 20,000 m below the sea level. The interpretation of the density model identified structures related to the different volcanic stages of Gran Canaria. Several deep‐rooted high‐density structures represent the intrusive bodies emplaced in the early formation of Gran Canaria and the magma plumbing system of the Miocene volcanic edifices. A low‐density body in the center of the island may be associated with the syenitic core of the felsic central volcanic edifice (Tejeda Caldera). Shallow low‐density structures identified fractures which acted as feeder dikes of monogenetic volcanoes during the rejuvenated stage. Finally, the NW‐SE rift, which is the most important volcano‐tectonic structure of Gran Canaria, has a characteristic gravimetric signature and represents a long‐lived extensional fracture zone that has controlled the volcanic activity at least since the Miocene.