Formación de dolomita y huntita en depósitos de moon-milk en la Cueva de Castañar de Ibor (Cáceres)

Abstract

The Castañar the Ibor Cave formed by dissolution of the Precambrian dolostone beds of the Ibor Group. The cave contains a variety of calcitic and aragonitic speleothems, and also moon-milk deposits composed of huntite, dolomite and minor hydromagnesite. Both huntite and dolomite tend to form spheroidal structures. Huntite formation occurred mostly on microbial films that in part corrode the speleothems. Spherulites of dolomite could form later on by transformation of the previously formed huntite, that acted as a precursor for dolomite formation. Both the huntite precursor and the microbial activity allow the presence of dolomite under environmental conditions.