Dataciones isotópicas de carbonatos continentales en el Pleistoceno superior de las Islas Chafarinas (N África, España)

Abstract

Las islas volcánicas de Chafarinas guardan un amplio registro sedimentario del Pleistoceno superior continental. El análisis radiomètrico de las muestras de calcretas y gasterópodos fósiles, presentes en la serie de la isla del Rey Francisco I, por medio de isótopos de Uranio y Carbono, nos ha servido para fechar este registro entre 100 y 20 ka BP.

Chafarinas Islands are a volcanic outcrop in the North edge of Africa, with an Upper Miocene-Pliocene age. The present cliffed landform result of an intensive marine action that has eroded the previous volcanic relief. Quaternary deposits and calcrete formations cover the most part of the planated surface of the islands, mainly in Rey Francisco I isle. Here we studied a wide geological section with 18 m of detritic and calcrete layers. Isotopie dating (230Th/234U and 14C) of these continental deposits (calcretes and shells) and their geological interpretation show a palaeoclimatic fluctuations along the Late Quaternary (100-20 ky BP).