Frostwork
From Wikipedia, the free encyclopedia
Frostwork is the term for a rare type of speleothem composed of needle-like growths of calcite or aragonite (a polymorph of calcite). In places the frostwork may grow on top of cave popcorn or boxwork. The origin of frostwork is somewhat controversial. Formation of cave frostwork has been attributed to moist, circulating air which, containing dissolved calcium carbonate, drifted against rock surfaces and coated them with the delicate crystals. Frostwork has also been attributed to water seepage from cave passageways in which there are relatively high evaporation rates.
Notable frostwork deposits are found in a number of caves in the Black Hills region of South Dakota, USA, most notable in Wind Cave National Park and Jewel Cave National Monument.
