Frostwork
Encyclopedia
Frostwork is a type of speleothem
(cave formation) composed of acicular ("needle-like") growths almost always composed of aragonite
(a polymorph
of calcite) or calcite
replaced by aragonite . It is a variety of anthodite
. In some caves frostwork may grow on top of cave popcorn
or boxwork
.
, 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.
s in the Black Hills
region of South Dakota
, USA, most notable in Wind Cave National Park
and Jewel Cave National Monument
. Perhaps the most extensive displays known are found in Lechuguilla Cave
, New Mexico.
Speleothem
A speleothem , commonly known as a cave formation, is a secondary mineral deposit formed in a cave. Speleothems are typically formed in limestone or dolostone solutional caves.-Origin and composition:...
(cave formation) composed of acicular ("needle-like") growths almost always composed of aragonite
Aragonite
Aragonite is a carbonate mineral, one of the two common, naturally occurring, crystal forms of calcium carbonate, CaCO3...
(a polymorph
Polymorphism (materials science)
Polymorphism in materials science is the ability of a solid material to exist in more than one form or crystal structure. Polymorphism can potentially be found in any crystalline material including polymers, minerals, and metals, and is related to allotropy, which refers to chemical elements...
of calcite) or calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
replaced by aragonite . It is a variety of anthodite
Anthodite
Anthodites are speleothems composed of long needle-like crystals situated in clusters which radiate outward from a common base. The "needles" may be quill-like or feathery...
. In some caves frostwork may grow on top of cave popcorn
Cave popcorn
Cave popcorn, or cave coral, is a very common cave formation. It actually comes in many sizes, shapes, and colors, but is most often found in small, knobby clusters resembling popcorn...
or boxwork
Boxwork
Boxwork is an uncommon type of mineral structure, or speleogen , occasionally found in caves and erosive environments....
.
Formation
The origin of frostwork is somewhat controversial. Formation of cave frostwork has been attributed to moist, circulating air which, containing dissolved calcium carbonateCalcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
, 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
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....
rates.
Occurrence
Notable frostwork deposits are found in a number of caveCave
A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...
s in the Black Hills
Black Hills
The Black Hills are a small, isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, USA. Set off from the main body of the Rocky Mountains, the region is something of a geological anomaly—accurately described as an "island of...
region of South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
, USA, most notable in Wind Cave National Park
Wind Cave National Park
Wind Cave National Park is a United States national park north of the town of Hot Springs in western South Dakota. Established in 1903 by President Theodore Roosevelt, it was the seventh U.S. National Park and the first cave to be designated a national park anywhere in the world. The cave is...
and Jewel Cave National Monument
Jewel Cave National Monument
Jewel Cave National Monument contains Jewel Cave, currently the second longest cave in the world, with just over of mapped passageways. It is located approximately west of the town of Custer in South Dakota's Black Hills...
. Perhaps the most extensive displays known are found in Lechuguilla Cave
Lechuguilla Cave
Lechuguilla Cave is, as of June 2011, the sixth longest cave known to exist in the world, and the deepest in the continental United States , but it is most famous for its unusual geology, rare formations, and pristine condition....
, New Mexico.