school energy&environment

Caves in the ice and ice in the caves

Many Karst caves, dug into the rock, contain ice inside, in amounts that can be also considered abundant. These must not be confused with ice caves that are formed entirely within the glacier. The mechanisms that lead to the formation of ice in a cave are numerous and very complex. Seasonal ice may form in winter because the water that percolates through the crevices freezes near the openings, where the temperatures of the cave are influenced by the cold external temperature. Larger quantities of ice may form due to the freezing of small surfaces of water, as it has been reported, for example, in some caves in the Northern Grigna mountains, in the Prealps of Lombardy: here the ice is quite ancient and can be dated back to the beginning of industrial activities. In some cases the nearness to a glacier may push glacier ice into the galleries as in the case of the famous Castelguard Cave in North America. In other cases, ice forms due to the accumulation and transformation of snow that falls into the entrance shaft. The study of the ice found in caves, performed in an analogous manner as the study of cores taken from the glaciers, can provide extremely precious information regarding more recent climatic variations.