Ice in caves
In high mountain or high latitude environments, many caves can contain ice deposits, at times even in great quantities. In winter, the most common cause of ice formation in caves is the freezing of water percolating through fractures and joints close to the entrances, where the cave temperature is influenced by the bitterly cold external one. At times small frozen lakes may form, where ice may remain for several years. At high altitudes, ice is formed due to the accumulation and transformation of snow fallen into sinholes or shafts at the entrance. The study of ice in caves, approached in the same way as the study of cores collected from glaciers, through the analysis of isotopes and chemical composition, can give precious information on recent climatic variations.