Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) A corrigendum has been published Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by MARTÍNEZ, J. A. Articles by CABALLERO, E. Search for Related Content GeoRef GeoRef Citation

Natural acid sulphate alteration in bentonites (Cabo de Gata, Almeria, SE Spain)

Estación Experimental del Zaidín, CSIC, Profesor Albareda 1, 18008 Granada, Spain

^* E-mail: ecabal{at}eez.csic.es

(Received 7 March 2006; revised 30 October 2006)

This study is located on the bentonite outcrop of ‘El Toril’ (Cabo de Gata, Almeria, Spain), where acid solutions have resulted in an alteration front that has caused physical, chemical and mineralogical changes in the bentonite material. The main objective is to assess these changes and to draw a model of evolution of this front in the outcrop. The most important chemical and mineralogical changes observed consist mainly of the loss of mass in the bentonite, the formation of kaolinite, the precipitation of jarosite and alunite from leachates and important changes in the rare earth element distribution pattern. No sulphurs have been identified in the pyroclastic rock at the top of the outcrop, but the presence of dissolution marks and the high concentrations of As, Pb and V in the rock overlying the bentonite point towards the existence, in principle, of these sulphurs and suggest that meteoric alteration is mainly responsible for the genesis of the outcrop.

KEYWORDS: bentonites, Cabo de Gata, Spain, acid sulphate alteration, smectite