Hoodoo (geology) - AbsoluteAstronomy.com

A hoodoo is a tall, thin spire of rock

Rock (geology)

In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

that protrudes from the bottom of an arid

Arid

A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...

drainage basin

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

or badland. Hoodoos consist of relatively soft rock topped by harder, less easily eroded stone that protects each column from the elements. They typically form within sedimentary rock

Sedimentary rock

Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....

and volcanic rock formations.

They are mainly located in the desert in dry, hot areas. In common usage, the difference between hoodoos and pinnacle

Pinnacle

A pinnacle is an architectural ornament originally forming the cap or crown of a buttress or small turret, but afterwards used on parapets at the corners of towers and in many other situations. The pinnacle looks like a small spire...

s or spire

Spire

A spire is a tapering conical or pyramidal structure on the top of a building, particularly a church tower. Etymologically, the word is derived from the Old English word spir, meaning a sprout, shoot, or stalk of grass....

s is that hoodoos have a variable thickness often described as having a "totem pole

Totem pole

Totem poles are monumental sculptures carved from large trees, mostly Western Red Cedar, by cultures of the indigenous peoples of the Pacific Northwest Coast of North America...

-shaped body." A spire, on the other hand, has a smoother profile or uniform thickness that tapers from the ground upward.

Hoodoos range in size from that of an average human

Human

Humans are the only living species in the Homo genus...

to heights exceeding a 10-story building. Hoodoo shapes are affected by the erosional patterns of alternating hard and softer rock layers. Mineral

Mineral

A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

s deposited within different rock types cause hoodoos to have different colors throughout their height.

Occurrence

Hoodoos are commonly found in the High Plateaus region of the Colorado Plateau

Colorado Plateau

The Colorado Plateau, also called the Colorado Plateau Province, is a physiographic region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. The province covers an area of 337,000 km2 within western Colorado, northwestern New Mexico,...

and in the Badlands

Badlands

A badlands is a type of dry terrain where softer sedimentary rocks and clay-rich soils have been extensively eroded by wind and water. It can resemble malpaís, a terrain of volcanic rock. Canyons, ravines, gullies, hoodoos and other such geological forms are common in badlands. They are often...

regions of the Northern Great Plains (both in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

). While hoodoos are scattered throughout these areas, nowhere in the world are they as abundant as in the northern section of Bryce Canyon National Park

Bryce Canyon National Park

Bryce Canyon National Park is a national park located in southwestern Utah in the United States. The major feature of the park is Bryce Canyon which, despite its name, is not a canyon but a giant natural amphitheater created by erosion along the eastern side of the Paunsaugunt Plateau...

, located in the U.S. state of Utah

Utah

Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

(see geology of the Bryce Canyon area

Geology of the Bryce Canyon area

The exposed geology of the Bryce Canyon area in Utah shows a record of deposition that covers the last part of the Cretaceous Period and the first half of the Cenozoic era in that part of North America...

).

Hoodoos are a tourist attraction in the Cappadocia

Cappadocia

Cappadocia is a historical region in Central Anatolia, largely in Nevşehir Province.In the time of Herodotus, the Cappadocians were reported as occupying the whole region from Mount Taurus to the vicinity of the Euxine...

region of Turkey

Turkey

Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...

where houses have been carved from these formations. These rock formations were depicted on the reverse

Obverse and reverse

Obverse and its opposite, reverse, refer to the two flat faces of coins and some other two-sided objects, including paper money, flags , seals, medals, drawings, old master prints and other works of art, and printed fabrics. In this usage, obverse means the front face of the object and reverse...

of the Turkish 50 new lira

Turkish lira

The Turkish lira is the currency of Turkey and the de facto independent state of the Turkish Republic of Northern Cyprus. The lira is subdivided into 100 kuruş...

banknote of 2005-2009.

In French

French language

French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...

, they are called demoiselles coiffées ("ladies with hairdos") and a number of them are found in the Alpes-de-Haute-Provence

Alpes-de-Haute-Provence

Alpes-de-Haute-Provence is a French department in the south of France, it was formerly part of the province of Provence.- History :Nord-de-Provence was one of the 83 original departments created during the French Revolution on 4 March 1790...

; one of the best-known examples is the formation called Demoiselles Coiffées de Pontis

Demoiselles Coiffées de Pontis

The Demoiselles Coiffées de Pontis is a rock formation in Pontis, near Embrun in the French Alps, located on the edge of the Lac de Serre-Ponçon...

.

Đavolja Varoš (Devil's Town) hoodoos in Serbia feature 202 exotic formations described as earth pyramids or "towers", as the locals refer to them. Since 1959, Đavolja Varoš has been protected by the state, and it is also a nominee in the New Seven Wonders of Nature campaign.

The hoodoo stones on the northern coast of Taiwan

Taiwan

Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...

are unusual for their coastal setting. The stones formed as the seabed rose rapidly out of the ocean during the Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

epoch. Efforts have been made to slow the erosion in the case of iconic specimens in Wanli.

Formation within volcanic rocks

The geology of areas where fairy chimneys form typically comprises a thick layer of tuff

Tuff

Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...

(consolidated volcanic ash), covered by a thin layer of basalt

Basalt

Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

or other volcanic rocks that are more resistant to erosion than the underlying tuff. Over time, cracks in the basalt allow the much softer tuff to be eroded and washed away. Fairy chimneys are formed where a small cap or boulder of the original basalt remains, and protects a cone of tuff beneath it from erosion. Eventually, the tuff will be undercut to the extent that the cap falls off, and the remaining cone is then quickly eroded.

External links

National Park Service: Bryce Canyon National Park: Nature and Geology - Hoodoos (adapted public domain text)
Hoodoos (Erdpyramiden - demoiselles coiffées) world-wide

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Occurrence

Formation within volcanic rocks

See also

Further reading

External links