Resumen de Mineralogy of speleothems in magmatic rock caves
Juan Ramón Vidal Romaní, Marcos Vaqueiro Rodríguez, Jorge Sanjurjo Sánchez, L. González López
These speleothems are formed by 2 types of mineral components: inherited and authigenic. The first come from the rock destruction and are normally crystalline. The second are formed in the same speleothem and may be amorphous (opal-A) or crystalline (whiskers and nanominerals). Both types of minerals have genetic relation because whiskers and nanominerals are formed during the dehydration of the silicon hydrogel at the end of the wet stage of the speleothem. Due to their scarce concentration they may be only analyzed either morphologically (punctual symmetry) or by Scanning Electron Microscopy (S.E.M). The following were identified: gypsum, anhydrite, evansite, bolivarite, struvite, pigotite, taranakite, allophane, hematite, goethite, halite, calcite, aragonite, plumboaragonite, malachite, etc. The formation of these minerals is closely related to the microbiological activity except for the carbonate whiskers which are originated by the sequestration of the atmospheric CO2.
