Facies asociadas a deslizamientos gigantes en Fuerteventura (Islas Canarias)

Abstract

Sixteen million years ago, the northern part of the Initial Ridge volcano of the island of Fuerteventura underwent a gravitational slide throughout its western flank. At present, the remains of the debris avalanche produced by the sliding blanket the ocean floor to the west of the island and are also present in the northern and central parts of Fuerteventura. A field study of these deposits has permitted to establish a series of lithofacies, whose sedimentological and lithological characteristics allow the reconstruction of the processes involved. The decapitation of the interior of the volcano (the magma chamber) during the slide produced a laterally directed blast that generated a stratified pyroclastic dense flow (PDF) that covered the previous debris avalanche deposits. The slide created a huge depression open to the West, which continued to be filled by epiclastic materials from secondary slides that affected the walls of the large depression, and also by the materials resulting from the reworking of both the debris avalanche and the blast deposits. This filling process was accompanied by renewed volcanic activity in the form of subaerial eruptions, some of them of hydrovolcanic character.