El moonmilk, un depósito endokárstico singular. Presencia en cavidades españolas

Abstract

Moonmilk is an endokarstic deposit which composition and genesis is controversial. In this work, the presence of moonmilk-type deposits is summarized and studied in four Spanish caves, located in areas with different geological, geographical and environmental conditions. The theories about their origin proposed in the literature are discussed and considered in relation to the studied cases. In the present study the moonmilk has been found under very different endokarstic environmental conditions, from cold to warm caves, with main air temperature ranging from less than 70°C up to 20PC. According to their composition, two main types of moonmilk have been observed: calcium-rich and magnesium-rich carbonates, depending on the original composition of the rock where the cave is developed. The magnesium-rich carbonate moonmilks can be mono or polimineral, possibly depending on the environmental and physico-chemical characteristics of the deposit surroundings and of the water composition. In all the cases the presence of moonmilk is related to the arrival to the cave, by porous and very small fisures, of waters with a very high C02 pressure. Signs of microbiological activity participation on the moonmilk formation have not been observed