Mineralogical Reconnaisance of Caves from Mallorca Island

Eighteen caves on the Mallorca Island were investigated with respect to their mineralogy. Sixteen minerals, divided into four chemical groups, were identified and described using X-ray diffraction, infrared, thermal, and scanning electron microscope analyses. Calcite is the only mineral found in every sampled cave. Aragonite, gypsum, and hydroxylapatite occur in speleothems from four different caves. In addition, a few other carbonates, phosphates, and silicates were identified in crusts, minute crystals, and earthy masses. The mechanisms responsible for deposition of minerals in the Majorcan caves are: (i) precipitation from percolating water, (ii) precipitation in the freshwater/seawater mixing zone, (iii) reaction between the bedrock and various speleothems, and the phosphate-rich solutions derived from bat guano, and (iv) mineral phase transition. Cova de sa Guitarreta and Cova de ses Rates Pinyades were confirmed to be two outstanding cavities with respect to their mineralogy, both hosting eight true cave minerals. Their phosphate association is diverse and interesting