Diana Fountain in Bushy Park 3 (cropped)

In geology, frostwork is a type of

speleothem A speleothem (; ) is a geological formation by mineral deposits that accumulate over time in natural caves. Speleothems most commonly form in calcareous caves due to carbonate dissolution reactions. They can take a variety of forms, dependi ...

(cave formation) with acicular ("needle-like") growths almost always composed of

aragonite Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including pre ...

(a polymorph of calcite) or

calcite Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratc ...

replaced aragonite. It is a variety of

anthodite Anthodites (Greek ἄνθος ''ánthos'', "flower", ''-ode'', adjectival combining form, ''-ite'' adjectival suffix) are speleothems (cave formations) composed of long needle-like crystals situated in clusters which radiate outward from a common ...

. Frostwork can also be made of

opal Opal is a hydrated amorphous form of silica (SiO2·''n''H2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline form ...

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywa ...

. In some caves frostwork may grow on top of cave popcorn or

boxwork In geology, boxwork is defined as a honeycomb-like structure that can form in some fractured or jointed sedimentary rocks. If the fractures in the host rock are mineralized, they can become more resistant to weathering than the surrounding rock, ...

. In architecture frost-work or frostwork refers to a style of rustication carved with a vertically-oriented pattern evoking hanging pond-weed or algae, or icicles. It is mainly found in garden architecture, where water is to flow over or near the surface.Looking at buildings
"Rustication" Other decorative arts may use the term for other decorative patterns imitating frost or ice.

Formation

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 Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when h ...

rates.

Occurrence

Notable frostwork deposits are found in a number of

cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering of rock and often extend deep underground. The word ''cave'' can refer to smaller openings such as sea ...

s in the

Black Hills The Black Hills ( lkt, Ȟe Sápa; chy, Moʼȯhta-voʼhonáaeva; hid, awaxaawi shiibisha) is an isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, United States. Black ...

region of

South Dakota South Dakota (; Sioux: , ) is a U.S. state in the North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota and Dakota Sioux Native American tribes, who comprise a large po ...

, US, most notable in

Wind Cave National Park Wind Cave National Park is an American national park located north of the town of Hot Springs in western South Dakota. Established on January 3, 1903 by President Theodore Roosevelt, it was the sixth national park in the U.S. and the first c ...

and

Jewel Cave National Monument Jewel Cave National Monument contains Jewel Cave, currently the third longest cave in the world, with of mapped passageways. It is located approximately west of the town of Custer in Black Hills of South Dakota. It became a national monument ...

and Timpanogos Cave in

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to its ...

. Perhaps the most extensive displays known are found in

Lechuguilla Cave At , Lechuguilla Cave is the eighth-longest explored cave in the world and the second deepest () in the continental United States. It is most famous for its unusual geology, rare formations, and pristine condition. The cave is named for the c ...

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ...

, US.

Gallery

File:Tropfsteine.svg, Diagram of dripstone cave structures (frostwork labelled AA) File:Popcorn-with-Frostwork.jpg, Cave popcorn with frostwork

References

External links

Wind Cave National Park: Speleothems
Speleothems {{geology-stub