U-series dating of speleothems from the Sierra del Endrinal (Grazalema Mountains, S Spain)

Abstract

The uranium-series method is applied to date relic flowstone from karstic mountains in the south of Spain. Geomorphological mapping shows three staircased erosion surfaces with a typical karst landform. Exhumed flowstones fill the surficial palaeosinkholes and open fractures. Some of the samples analysed were impure carbonates consequently the leachate–leachate method was used to obtain activity ratios in the carbonate fraction. The ages obtained range from 34.4 ky to 266 ky and are grouped in four periods: 30–50 ky, 90–110 ky, 150 ky and 230–270 ky. All these periods are related to the warm climate oxygen isotope stages 3 and 5. Practically all locations present secular equilibrium in uranium isotopes.