In
geology
Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth ...
, boxwork is defined as a
honeycomb
A honeycomb is a mass of Triangular prismatic honeycomb#Hexagonal prismatic honeycomb, hexagonal prismatic cells built from beeswax by honey bees in their beehive, nests to contain their brood (eggs, larvae, and pupae) and stores of honey and pol ...
-like structure that can form in some fractured or jointed
sedimentary
Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedime ...
rocks. If the fractures in the host rock are mineralized, they can become more resistant to weathering than the surrounding rock, and subsequent erosion can produce boxwork structures. In
mining geology
Mining geology is an applied science which combines the principles of economic geology and mining engineering to the development of a defined mineral resource. Mining geologists and engineers work to develop an identified ore deposit to economica ...
, boxwork is a set of (typically)
quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
-lined cavities, retaining the shape of the dissolved
ore
Ore is natural rock or sediment that contains one or more valuable minerals, typically including metals, concentrated above background levels, and that is economically viable to mine and process. The grade of ore refers to the concentration ...
mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
s, in
gossan
Gossan (eiserner hut or eisenhut) is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein. In the ''classic'' gossan or iron cap all that remains is iron oxides and quartz, often ...
s. In classical geology or
mineralogy
Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical mineralogy, optical) properties of minerals and mineralized artifact (archaeology), artifacts. Specific s ...
these mineral casts would not be called boxwork, but would instead be called
pseudomorph
In mineralogy, a pseudomorph is a mineral or mineral compound that appears in an atypical form (crystal system), resulting from a substitution process in which the appearance and dimensions remain constant, but the original mineral is replaced b ...
s, or epimorphs. In
cave
Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...
geology, boxwork is an uncommon type of mineral structure, or
speleogen (similar to a
speleothem
A speleothem (; ) is a geological formation made 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, depen ...
, but formed by erosion rather than accretion), occasionally found in caves and
erosive environments.
Caves
According to KellerLynn, "Boxwork is a speleogen, forming when bedrock between preexisting calcite veins were preferentially weathered away as the cave developed."
Boxwork is commonly composed of thin blades of the mineral
calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
that project from cave walls or ceilings that intersect one another at various angles, forming a box-like or
honeycomb
A honeycomb is a mass of Triangular prismatic honeycomb#Hexagonal prismatic honeycomb, hexagonal prismatic cells built from beeswax by honey bees in their beehive, nests to contain their brood (eggs, larvae, and pupae) and stores of honey and pol ...
pattern. The boxwork fins once filled cracks in the rock before the host cave formed. As the walls of the cave began to dissolve away, the more resistant vein and crack fillings did not, or at least dissolved at a slower rate than the surrounding rock, leaving the calcite fins projecting from the cave surfaces.
Some of the most extensive boxwork deposits in the world are found in
Wind Cave
Wind Cave National Park is a national park of the United States 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 t ...
,
Wind Cave National Park
Wind Cave National Park is a national park of the United States 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 t ...
in
South Dakota
South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux ...
, United States. These boxwork deposits consist of calcite, along with
manganese
Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...
and
dolomite that precipitated in fractured host limestone. The limestone preferentially dissolved, leaving a crystalline calcite boxwork behind. Other outstanding examples occur in
Cody Caves,
Cody Caves Provincial Park in
British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
, Canada. Boxwork can also be seen at
Jewel Cave National Monument
Jewel Cave National Monument contains Jewel Cave, currently the fifth longest cave in the world and second longest cave in the United States, with of mapped passageways as of May 2024. It is located approximately west of the town of Custer in ...
(near Wind Cave), and at
Inner Space Cavern
Inner Space Cavern (Also known as Laubach Cave) is a Solutional cave, karst cave located in Georgetown, Texas. The cavern was formed by water passing through Edwards limestone. The cavern is estimated to be around 20–25 million years old but h ...
near
Georgetown, Texas
Georgetown is a city in Texas and the county seat of Williamson County, Texas, United States. The population was 67,176 at the 2020 census, and according to 2024 census estimates, the city is estimated to have a population of 101,344. It is no ...
, United States.
Gallery
File:Cave Boxwork often call cratework when this large. WInd Cave.JPG, Large boxwork ("cratework") in Wind Cave
Wind Cave National Park is a national park of the United States 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 t ...
.
File:Calcite boxwork, Wind Cave.jpg, Boxwork removed from Wind Cave.
File:Tropfsteine.svg, Diagram of dripstone cave structures (boxworks labelled AE)
References
External links
Wind Cave National Park: Origin of Boxwork
{{Caves
Speleothems
Economic geology