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The Wichita Mountains are located in the southwestern portion of the U.S. state of
Oklahoma Oklahoma (; Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a state in the South Central region of the United States, bordered by Texas on the south and west, Kansas on the north, Missouri on the northeast, Arkansas on the east, New ...
. It is the principal relief system in the Southern Oklahoma Aulacogen, being the result of a failed continental rift. The mountains are a northwest-southeast trending series of rocky promontories, many capped by 500 million-year old granite. These were exposed and rounded by weathering during the Pennsylvanian &
Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...
Periods. The eastern end of the mountains offers of topographic relief in a region otherwise dominated by gently rolling grasslands. The mountains are home to numerous working ranches and quarry operations, the state reformatory, recreational homes and campsites, and scenic parklands.
Fort Sill Fort Sill is a United States Army post north of Lawton, Oklahoma, about 85 miles (136.8 km) southwest of Oklahoma City. It covers almost . The fort was first built during the Indian Wars. It is designated as a National Historic Landmark ...
, home of the U.S. Army Field Artillery School, occupies a large portion of the southeastern end of the mountains.


Recreation

The Wichita Mountains National Wildlife Refuge, a favorite for hikers and rock climbers in the region, is located adjacent to
Cache Cache, caching, or caché may refer to: Places United States * Cache, Idaho, an unincorporated community * Cache, Illinois, an unincorporated community * Cache, Oklahoma, a city in Comanche County * Cache, Utah, Cache County, Utah * Cache Count ...
, Medicine Park, Indiahoma, and historic Meers, and is a short drive from Lawton and Walters.
Bison Bison are large bovines in the genus ''Bison'' (Greek: "wild ox" (bison)) within the tribe Bovini. Two extant taxon, extant and numerous extinction, extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'' ...
, elk and deer are protected on the wildlife refuge. The refuge also manages a herd of longhorn cattle. A scenic highway traversing the park permits leisurely views of these and other fauna. Backcountry camping is available in the Charon Gardens Wilderness area. The park is home to a small number of fishing lakes. There are several trails for hiking. The Treasure Lake Job Corps site is located here. Additional points of interest include the refuge's visitors center, Holy City of the Wichitas, Quanah Parker Lake & Dam, Lake Jed Johnson, and Lake Lawtonka. Great Plains State Park is located near the geographic center of the Wichita Mountains, north of the town of Mountain Park. Quartz Mountain Nature Park and Arts Center is a recreation area located north of the city of Altus.


Geography

At 2,464 ft (751 m) Mount Scott is the second highest mountain within the Wichita Mountains National Wildlife Refuge boundary. Mount Pinchot in the Special Use Area is taller. Splinter, Dale K. and Marston, Richard A. "Wichita Mountains". ''Encyclopedia of Oklahoma History and Culture''. Oklahoma Historical Society.
Accessed May 16, 2016.
A paved road leads to the summit of Mount Scott, offering views of the granite promontories to the west, the wind farm on the Slick Hills to the north, the lakes to the south and east,
Fort Sill Fort Sill is a United States Army post north of Lawton, Oklahoma, about 85 miles (136.8 km) southwest of Oklahoma City. It covers almost . The fort was first built during the Indian Wars. It is designated as a National Historic Landmark ...
, and Lawton. The highest peak in the Wichita Mountains (including areas outside the refuge) is Haley Peak, at . Haley Peak is located on private property just outside the northwest corner of the refuge.


History

When the area was part of Indian reservations and therefore off-limits to non-Native Americans, the Wichita Mountains were rumored to contain rich gold deposits. When the area was first opened up for settlement, many prospectors staked mining claims, and towns were laid out to serve the presumed bonanzas, but no economic deposits were found. The gold boom was prolonged by some unscrupulous assayers who found gold in every sample, but the miners eventually gave up, leaving behind ghost towns such as Wildman, Oklahoma.


Geology


Overview

The Wichita Mountains are rocky promontories and rounded hills made of red and black
igneous Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma ...
rocks, light-colored
sedimentary Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...
rocks, and boulder conglomerates. The Wichita Mountains were formed in four distinct geologic episodes following a failed continental rift. #
Magmatism Magmatism is the emplacement of magma within and at the surface of the outer layers of a terrestrial planet, which solidifies as igneous rocks. It does so through magmatic activity or igneous activity, the production, intrusion and extrusion of ...
induced by continental
rifting In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben w ...
just prior to and in the
Cambrian The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ag ...
Period produced the
granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies unde ...
s and
rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals ( phenocrysts) in an otherwise fine-grained groundmass. The miner ...
s (the red rocks), gabbroic rocks,
anorthosite Anorthosite () is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals mos ...
s, and
diabase Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grain ...
s (the black rocks). # Subsidence resulted in burial by
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...
s and carbonates (the light-colored rocks) during the early
Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ...
. # Uplift during the Pennsylvanian Ouachita Orogeny brought these rocks to the surface as mountains. #
Weathering Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), ...
and
erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is di ...
during the
Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...
Period flattened the mountains and produced a mantle of conglomerates. The mountains themselves are Permian landforms covered and preserved by river-borne sediments in the Permian and partially excavated only in recent geological times. Exposure of these fossil mountains is greatest towards the southeast; much of the western part of the Permian range remains buried under
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...
s and
mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...
s.


Details

The
geologic Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ear ...
history of the region began with the deposition of late
Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...
to early
Cambrian The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ag ...
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...
s collectively known as the Tillman metasedimentary group.M. Charles Gilbert, 1982, ''Geologic setting of the eastern Wichita Mountains with a brief discussion of unresolved problems'', in Gilbert, M.C. and Donovan, R.N., eds., Geology of the Eastern Wichita Mountains, Southwestern Oklahoma, Oklahoma Geological Survey Guidebook 21, p. 1-30. These sediments were intruded by a coarse
mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks incl ...
layered complex as the region began to
rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben wi ...
apart during breakup of the
Neoproterozoic The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago. It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is pre ...
continent,
Pannotia Pannotia (from Greek: '' pan-'', "all", '' -nótos'', "south"; meaning "all southern land"), also known as the Vendian supercontinent, Greater Gondwana, and the Pan-African supercontinent, was a relatively short-lived Neoproterozoic supercontinent ...
.D.A. McConnell and Gilbert, M.C., 1990, ''Cambrian extensional tectonics and magmatism within the Southern Oklahoma Aulacogen'', Tectonophysics, 174 p. 147-157. The exposed portion of this unit, named the Glen Mountains Layered Complex, consists of
gabbro Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is ch ...
,
anorthosite Anorthosite () is a phaneritic, intrusive igneous rock characterized by its composition: mostly plagioclase feldspar (90–100%), with a minimal mafic component (0–10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals mos ...
and troctolite. Recent high-precision dating yields an age of 532.49 ± 0.15 Ma. These are the dark gray rocks found throughout the Raggedy Mountains, the central lowlands region of the wildlife refuge, and to the immediate north of the refuge.Roger W. Cooper, 1986, ''Platinum-group-element potential of the Glen Mountains Layered Complex'', in Gilbert, M.C. ed., Petrology of the Cambrian Wichita Mountains Igneous Suite, Oklahoma Geological Survey Guidebook 23, p. 65-72. Uplift and erosion followed, as the layered complex is unconformably overlain by the extensive
lava Lava is molten or partially molten rock ( magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or ...
flows of the Carlton
Rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals ( phenocrysts) in an otherwise fine-grained groundmass. The miner ...
Group. The rhyolites are a brown-red to orange
porphyritic Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning a ...
rock with 5–10 mm orange-colored
alkali feldspar Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...
crystals. Most of the rounded hills on
Fort Sill Fort Sill is a United States Army post north of Lawton, Oklahoma, about 85 miles (136.8 km) southwest of Oklahoma City. It covers almost . The fort was first built during the Indian Wars. It is designated as a National Historic Landmark ...
are made of this rhyolite, including Medicine Bluffs. Additional exposure of the rhyolite is found in Blue Creek Canyon, where Oklahoma Highway 58 cuts through the Slick Hills. Tabular intrusions of
granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies unde ...
and plutons of hydrous
gabbro Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is ch ...
exploited the boundary between the layered complex and the rhyolites.Hogan, John P., Price, J.D., and Gilbert, M.C., 1998, ''Magma traps and driving pressure: consequences for pluton shape and emplacement in an extensional regime.'', Journal of Structural Geology, 20 pp. 1155-68. The granites, collectively named the Wichita Granite Group, vary slightly in composition and texture. The granites form the peaks and highlands in the eastern Wichitas and the isolated peaks of the western Wichitas. Some are equigranular, but most are
porphyritic Porphyritic is an adjective used in geology to describe igneous rocks with a distinct difference in the size of mineral crystals, with the larger crystals known as phenocrysts. Both extrusive and intrusive rocks can be porphyritic, meaning a ...
. The Mount Scott Granite is the most extensively exposed Wichita Granite. It forms the topographic feature from which it takes its name, and it is distributed throughout the northern half of the wildlife refuge. Dark rounded
alkali feldspar Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...
s, typically one centimeter or less in diameter, dominate the porphyritic texture of this rock.Clifford A. Merritt, 1965, ''Mt. Scott Granite, Wichita Mountains, Oklahoma'', Oklahoma Geology Notes, 25, pp. 263-72. SiO2 levels in this granite range from 72.8% to 75.8%. Relatively small and compositionally distinct
pluton In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...
s, known as the Roosevelt Gabbros, are found in the eastern and central Wichita Mountains. Like the layered complex, these are dark rocks. Unlike the layered complex, they contain appreciable amounts of
biotite Biotite is a common group of phyllosilicate minerals within the mica group, with the approximate chemical formula . It is primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more alumi ...
, a mineral that forms in
magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural s ...
s with elevated dissolved water. One of these bodies, the Mount Sheridan Gabbro, is exposed in roadcuts at Meers and underlies the Mount Scott Granite on the north side of the wildlife refuge. Weathered gabbroic soils are thicker and support more vegetation than those generated on weathered granite, so the tree line on the north side of Mount Sheridan approximates the contact between the Mount Sheridan Gabbro and the Mount Scott Granite. Geologic relationships suggest that the granites and gabbros intruded at depths no greater than half a kilometer in the crust. Minor uplift ensued, and magmatism concluded with the intrusive emplacement of subvolcanic features:
rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals ( phenocrysts) in an otherwise fine-grained groundmass. The miner ...
and
diabase Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grain ...
dikes Dyke (UK) or dike (US) may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), a subvertical sheet-like intrusion of magma or sediment * Dike (mythology), ''Dikē'', the Greek goddess of moral justice * Dikes, ...
. These are poorly exposed, with the exception of a large diabase dike in the Mount Scott Granite revealed during the recent widening of Oklahoma State Highway 49, just west of
Interstate 44 Interstate 44 (I-44) is a major Interstate Highway in the central United States. Although it is nominally an east–west road as it is even-numbered, it follows a more southwest–northeast alignment. Its western terminus is in Wichita Fal ...
. Following the cessation of
magmatism Magmatism is the emplacement of magma within and at the surface of the outer layers of a terrestrial planet, which solidifies as igneous rocks. It does so through magmatic activity or igneous activity, the production, intrusion and extrusion of ...
, the region subsided and was inundated by a shallow sea, resulting in the deposition of detrital sediments followed by carbonates.R. Nowell Donovan, Ragland, D., Rafalowski, M., McConnell, D., Beauchamp, W., Marcini, W.R., and Sanderson, D.J. 1988, ''Pennsylvanian deformation and Cambro-Ordovician sedimentation in the Blue Creek Canyon, Slick Hills, southwestern Oklahoma,'' in Hayward, O.T., ed., Geological Society of America, Centennial Field Guide, 4, p. 127-34. The change marks the local expression of the Sauk Unconformity. The light-colored rocks exposed in the Slick Hills are lower
Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ...
marine sediments, and are equivalent to those exposed in the
Arbuckle Mountains The Arbuckle Mountains are an ancient mountain range in south-central Oklahoma in the United States. They lie in Murray, Carter, Pontotoc, and Johnston counties.
, 100 km to the east. During the Pennsylvanian Period (330–290 million years ago) the region was subjected to intense pressure during the continental collision or
orogeny Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted ...
which produced the
Ouachita Mountains The Ouachita Mountains (), simply referred to as the Ouachitas, are a mountain range in western Arkansas and southeastern Oklahoma. They are formed by a thick succession of highly deformed Paleozoic strata constituting the Ouachita Fold and Thru ...
to the east. This resulted in faulting and
folding Fold, folding or foldable may refer to: Arts, entertainment, and media * ''Fold'' (album), the debut release by Australian rock band Epicure *Fold (poker), in the game of poker, to discard one's hand and forfeit interest in the current pot *Above ...
striking along a WNW direction and includes the Arbuckle and Wichita Mountains of southern Oklahoma and the Amarillo Uplift of the
Texas Panhandle The Texas Panhandle is a region of the U.S. state of Texas consisting of the northernmost 26 counties in the state. The panhandle is a square-shaped area bordered by New Mexico to the west and Oklahoma to the north and east. It is adjacent to ...
. Up to of local uplift occurred during this time. This uplift locally created rugged mountains reduced by
erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is di ...
to their present state largely during the Pennslyvanian &
Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...
Periods. Extensive weathering produced the tors of the Charon Gardens region and the "river" of
boulder In geology, a boulder (or rarely bowlder) is a rock fragment with size greater than in diameter. Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive. In ...
s that descends the west slope of Mount Scott. Likewise, weathering produced the bowling-ball sized boulders in the Permian Post Oak Conglomerate locally found in and around the mountains. In addition to outcrops of the conglomerate, the boulders are preserved in the distinctive rock buildings of Medicine Park. As the Permian progressed,
river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of ...
sediments buried the Wichita Mountains, preserving them from further weathering. Recent geological erosion has removed these sediments, excavating these once buried fossil
landforms A landform is a natural or anthropogenic land feature on the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Landforms include hills ...
. The most common soil in the Wichita Mountains is Brico series, which has a topsoil of brown cobbly loam over a reddish brown to red cobbly clay loam or clay subsoil.


Notes


References


External links


Wichita Mountains
- Video footage of the area and a list of local activities and resources.
United States Fish and Wildlife Service: Official Wichita Mountains Wildlife Refuge Homepage

BikeUSA.com: Wichita Mountain Wildlife Refuge



Oklahoma Digital Maps: Digital Collections of Oklahoma and Indian Territory
* O'Dell, Larry
Holy City of the Wichitas Pageant
- ''Encyclopedia of Oklahoma History and Culture'' - Oklahoma Historical Society * Splinter, Dale K. and Marston, Richard A.
Wichita Mountains
- ''Encyclopedia of Oklahoma History and Culture'' - Oklahoma Historical Society * O'Dell, Larry
Wichita Mountains National Wildlife Refuge
- ''Encyclopedia of Oklahoma History and Culture'' - Oklahoma Historical Society {{Authority control Great Plains Mountain ranges of Oklahoma Volcanism of Oklahoma Cambrian volcanism Aulacogens Landforms of Comanche County, Oklahoma Geology of Oklahoma