Constitución geológica del Parque Nacional de la Caldera de Taburiente

Abstract

A thick submarine series crossed by diverse plutons and dyke systems (forming the Basal Complex of theIsland of La Palma), and a subaerial volcanic series with interspersed deposits of rock avalanches and sedimentary deposits of diverse origin, constitute the two geological units appearing at the National Park ofthe Caldera de Taburiente and its surroundings. The thick submarine sequence (with microfosils associationsof the Lower Pliocene) includes and old salic formation, and a younger basaltic-trachybasaltic sequence(2.5 Ma in age). The salic formation (3.1 Ma in age) corresponds to a submarine lobe-hyaloclastite trachyticcomplex probably related to the evolution of a former basaltic magma that would have led to the formationof a basaltic submarine shield, currently not exposed on the surface of the island.Intrusive in these materials appear, at least, two successive sequences of plutonic intrusions (with ages between 1.68 Ma and 1.05 Ma) formed by gabbros, melteigites and syenites related to the first subaerial volcanos (Garafía and Taburiente) that have happened in the evolution of the island.On the other hand, the central «Roques» (Roques Centrales) of the Caldera de Taburiente represent theerosive remains of the superposition of several run-out sheets formed from disintegration of huge blocksthat collapsed more than 47,000 years ago from the western, northern and eastern walls of the Caldera deTaburiente. Conglomerates coming from aqueous tractive flows (streamflows), filling palaeovalleys, weredeposited on those run-out sheets.The gravitational landslide of Playa de la Veta II, responsible for the partial destruction of the Lower Taburiente volcanic edifice, took place in two successive periods of collapse between which a remarkable archingprocess of the basal surface of the main landslide would have taken place, giving place to an elongated NNESSW directed, dome structure.