Wichita Mountains
Encyclopedia
The Wichita Mountains are located in the southwestern portion of the U.S. state
of Oklahoma
. The mountains are a northwest-southeast trending series of rocky promontories, many capped by 540 million-year old granite. These were exposed and rounded by weathering during the Permian
Period. The eastern end of the mountains offers 1000 feet (305 m) 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
, home of the U.S. Army Field Artillery School, occupies a large portion of the southeastern end of the mountains.
, Medicine Park
, Indiahoma
, and historic Meers
while just a short drive from Lawton
. Buffalo, elk and deer are protected on the 59020 acres (23,884.6 ha) 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 popular fishing lakes. There are numerous trails for hiking. It is also home to Treasure Lake Job Corps. Additional points of interest are the refuge
's visitors center, Holy City of the Wichitas, Quanah Parker Lake & Dam and Lake Lawtonka
.
Great Plains State Park
is located near the geographic center the Wichita Mountains, north of the town of Mountain Park.
Quartz Mountain Nature Park
and Arts Center is a noteworthy recreation area located north of the city of Altus.
is the second tallest mountain within the Wichita Mountains National Wildlife Refuge boundary. Mt. Pinchot in the Special Use Area is 12 feet (4 m) taller. A paved road leads to the summit of Mt. Scott, offering a stunning view 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
, and Lawton
. The highest peak in the Wichita Mountains (including areas outside the refuge) is Haley Peak, at 2481 ft (756.2 m). Haley Peak (officially unnamed) is located on private property just outside the northwest corner of the refuge.
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 sandstones
and shales
.
to early Cambrian
sandstone
s collectively known as the Tillman metasedimentary group. These sediments were intruded
by a coarse mafic
layered complex about 575 million years ago as the region began to rift apart in an aulacogen
during breakup of the Neoproterozoic continent, Pannotia. The exposed portion of this unit, named the Glen Mountains Layered Complex, consists of gabbro
, anorthosite
and troctolite
. These are the dark gray rocks found throughout the Raggedy Mountains, the central region of the wildlife refuge, and to the immediate north of the refuge.
Uplift and erosion followed, as the layered complex is uncomfomably
overlain by the extensive lava
flows of the Carlton Rhyolite
. This is an brown-red to orange porphyritic
rock with 5-10 mm orange-colored alkali feldspar
crystals. Most of the rounded hills on Fort Sill
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
and hydrous gabbro
exploited the boundary between the layered complex and the rhyolites. 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. Most are pink to brick red on fresh exposures. Some are equigranular
, others are porphyritic
. Some have a small concentration of sodium-rich amphiboles
. The Mount Scott Granite is the most extensively exposed Wichita Granite. It forms the topographic feature from which it takes it name, and it is distributed throughout the northern half of the wildlife refuge. Dark rounded alkali feldspar
s, typically one centimeter or less in diameter, dominate this rock.
Relatively small and compositionally distinct plutons
, 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
, a mineral that forms in magmas
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 vegitation 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
and diabase
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
. Following the cessation of magmatism, the region subsided and was inundated by a shallow sea, resulting in the deposition of detrital sediments followed by carbonates
. The light-colored rocks exposed in the Slick Hills are lower Paleozoic
marine sediments.
During the Pennsylvanian
Period (330–290 million years ago) the region was subjected to intense pressure during the continental collision or orogeny
which produced the Ouachita Mountains
to the east. This resulted in faulting and folding
striking
along a WNW direction and includes the Arbuckle
and Wichita Mountains of southern Oklahoma and the Amarillo Uplift of the Texas Panhandle
. Up to 20000 feet (6,096 m) of local uplift occurred during this time. This uplift locally created rugged mountains reduced by erosion
to their present state largely during the Permian
Period. Extensive weathering produced the tors of the Charon Gardens region and the "river" of boulder
s that decends the west slope of Mount Scott. Likewise, weathering produced the bowling-ball sized boulders in the Permian-age 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
sediments buried the Wichita Mountains, preserving them from further weathering. Geologically recent erosion is removing these sediments, excavating these once buried fossil landforms.
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
of Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
. The mountains are a northwest-southeast trending series of rocky promontories, many capped by 540 million-year old granite. These were exposed and rounded by weathering during the Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
Period. The eastern end of the mountains offers 1000 feet (305 m) 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
Fort Sill is a United States Army post near Lawton, Oklahoma, about 85 miles southwest of Oklahoma City.Today, Fort Sill remains the only active Army installation of all the forts on the South Plains built during the Indian Wars...
, 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 CacheCache, Oklahoma
Cache is a city in Comanche County, Oklahoma, United States. The population was 2,796 at the 2010 census. It is an exurb included in the Lawton, Oklahoma Metropolitan Statistical Area...
, Medicine Park
Medicine Park, Oklahoma
Medicine Park is a town in Comanche County, Oklahoma, United States, situated in the Wichita Mountains near the entrance to the Wichita Mountain Wildlife Refuge. Medicine Park has a long history as a vintage cobblestone resort town. Medicine Park is also located near the city of Lawton and Fort...
, Indiahoma
Indiahoma, Oklahoma
Indiahoma is a town in Comanche County, Oklahoma, United States. The population was 344 at the 2010 census. It is included as an exurb in the Lawton, Oklahoma, Metropolitan Statistical Area...
, and historic Meers
Meers, Oklahoma
Meers is a small town located on State Highway 115 in Comanche County, Oklahoma, in the foothills of the Wichita Mountains. Founded as a gold mining town in 1901, it was named for mine operator Andrew J. Meers...
while just a short drive from Lawton
Lawton, Oklahoma
The city of Lawton is the county seat of Comanche County, in the U.S. state of Oklahoma. Located in the southwestern region of Oklahoma approximately southwest of Oklahoma City, it is the principal city of the Lawton Oklahoma Metropolitan Statistical Area...
. Buffalo, elk and deer are protected on the 59020 acres (23,884.6 ha) 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
Charon Gardens Wilderness Area
The Charon's Garden Wilderness Area is part of the Wichita Mountains Wildlife Refuge in southwestern Oklahoma and is managed by the US Fish & Wildlife Service. It is located to the west of Medicine Park, Oklahoma and north of Lawton, Oklahoma. The wilderness area, dominated by rugged granite...
. The park is home to a small number of popular fishing lakes. There are numerous trails for hiking. It is also home to Treasure Lake Job Corps. Additional points of interest are the refuge
Wildlife refuge
A wildlife refuge, also called a wildlife sanctuary, may be a naturally occurring sanctuary, such as an island, that provides protection for species from hunting, predation or competition, or it may refer to a protected area, a geographic territory within which wildlife is protected...
's visitors center, Holy City of the Wichitas, Quanah Parker Lake & Dam and Lake Lawtonka
Lake Lawtonka
Lake Lawtonka is a lake in Comanche County in the state of Oklahoma in the United States.The lake is 2 square miles in area. It is formed by a dam 60 feet high and 375 feet long across Medicine Bluff Creek...
.
Great Plains State Park
Great Plains State Park
Great Plains State Park is a Oklahoma state park located in Kiowa County, Oklahoma. It is located near the city of Mountain Park, Oklahoma. Located south of Hobart off Hwy 183, Great Plains State Park is nestled between the Wichita Mountains and the Tom Steed Reservoir...
is located near the geographic center the Wichita Mountains, north of the town of Mountain Park.
Quartz Mountain Nature Park
Quartz Mountain Nature Park
Quartz Mountain Nature Park is located in southwest Oklahoma at the western end of the Wichita Mountains. It is operated by Oklahoma State Regents for Higher Education. Much of the area was formerly Quartz Mountain State Park, one of the original seven Oklahoma State Parks designated in 1935...
and Arts Center is a noteworthy recreation area located north of the city of Altus.
Geography
At 2,464 ft (751 m) Mount ScottMount Scott (Oklahoma)
Mount Scott is a prominent mountain just to the northwest of Lawton Oklahoma rising to a height of above sea level. It is located in the Wichita Mountains near Fort Sill Military Reservation and lies in the Wichita Mountains National Wildlife Refuge. The US Fish and Wildlife Service is responsible...
is the second tallest mountain within the Wichita Mountains National Wildlife Refuge boundary. Mt. Pinchot in the Special Use Area is 12 feet (4 m) taller. A paved road leads to the summit of Mt. Scott, offering a stunning view 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
Fort Sill is a United States Army post near Lawton, Oklahoma, about 85 miles southwest of Oklahoma City.Today, Fort Sill remains the only active Army installation of all the forts on the South Plains built during the Indian Wars...
, and Lawton
Lawton, Oklahoma
The city of Lawton is the county seat of Comanche County, in the U.S. state of Oklahoma. Located in the southwestern region of Oklahoma approximately southwest of Oklahoma City, it is the principal city of the Lawton Oklahoma Metropolitan Statistical Area...
. The highest peak in the Wichita Mountains (including areas outside the refuge) is Haley Peak, at 2481 ft (756.2 m). Haley Peak (officially unnamed) 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
In simplest terms, the Wichita Mountains are rocky promontories and rounded hills made of red and black igneous rocks, light-colored sedimentary rocks, and boulder conglomerates. The Wichita Mountains were formed in four distinct geologic episodes.- Magmatism induced by continental rifting just prior to and in the CambrianCambrianThe Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
Period produced the granitesGraniteGranite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
and rhyolitesRhyoliteThis page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
(the red rocks), gabbroic rocksGabbroGabbro refers to a large group of dark, coarse-grained, intrusive mafic igneous rocks chemically equivalent to basalt. The rocks are plutonic, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass....
, anorthositesAnorthositeAnorthosite is a phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar , and a minimal mafic component...
, and diabasesDiabaseDiabase or dolerite is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. In North American usage, the term diabase refers to the fresh rock, whilst elsewhere the term dolerite is used for the fresh rock and diabase refers to altered material...
(the black rocks). - Subsidence resulted in burial by sandstonesSandstoneSandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
and carbonatesLimestoneLimestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
(the light-colored rocks) during the early PaleozoicPaleozoicThe Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
. - Uplift during the PennsylvanianPennsylvanianThe Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods of the Carboniferous Period. It lasted from roughly . As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain...
Ouachita OrogenyOuachita orogenyThe Ouachita orogeny was a mountain building event that resulted in the folding and faulting of strata currently exposed in the Ouachita Mountains...
brought these rocks to the surface as mountains. - WeatheringWeatheringWeathering is the breaking down of rocks, soils and minerals as well as artificial materials through contact with the Earth's atmosphere, biota and waters...
and erosionErosionErosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
during the PermianPermianThe PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
Period flattened the mountains and produced a mantle of conglomeratesConglomerate (geology)A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
.
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 sandstones
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
and shales
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
.
Details
The geologic history of the region began with the deposition of late PrecambrianPrecambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...
to early Cambrian
Cambrian
The Cambrian is the first geological period of the Paleozoic Era, lasting from Mya ; it is succeeded by the Ordovician. Its subdivisions, and indeed its base, are somewhat in flux. The period was established by Adam Sedgwick, who named it after Cambria, the Latin name for Wales, where Britain's...
sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
s collectively known as the Tillman metasedimentary group. These sediments were intruded
Intrusion
An intrusion is liquid rock that forms under Earth's surface. Magma from under the surface is slowly pushed up from deep within the earth into any cracks or spaces it can find, sometimes pushing existing country rock out of the way, a process that can take millions of years. As the rock slowly...
by a coarse mafic
Mafic
Mafic is an adjective describing a silicate mineral or rock that is rich in magnesium and iron; the term is a portmanteau of the words "magnesium" and "ferric". Most mafic minerals are dark in color and the relative density is greater than 3. Common rock-forming mafic minerals include olivine,...
layered complex about 575 million years ago as the region began to rift apart in an aulacogen
Aulacogen
In geology, an aulacogen is a failed arm of a triple junction of a plate tectonics rift system. A triple junction beneath a continental plate initiates a three way breakup of the continental plate. As the continental break-up develops one of the three spreading ridges typically fails or stops...
during breakup of the Neoproterozoic continent, Pannotia. The exposed portion of this unit, named the Glen Mountains Layered Complex, consists of gabbro
Gabbro
Gabbro refers to a large group of dark, coarse-grained, intrusive mafic igneous rocks chemically equivalent to basalt. The rocks are plutonic, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass....
, anorthosite
Anorthosite
Anorthosite is a phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar , and a minimal mafic component...
and troctolite
Troctolite
Troctolite is a mafic intrusive rock type. It consists essentially of major but variable amounts of olivine and calcic plagioclase along with variable minor pyroxene. It is an olivine-rich, pyroxene-depleted relative of gabbro. However, unlike gabbro, no troctolite corresponds in composition to a...
. These are the dark gray rocks found throughout the Raggedy Mountains, the central region of the wildlife refuge, and to the immediate north of the refuge.
Uplift and erosion followed, as the layered complex is uncomfomably
Unconformity
An unconformity is a buried erosion surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger, but the term is used to describe...
overlain by the extensive lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
flows of the Carlton Rhyolite
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
. This is an brown-red to orange porphyritic
Porphyry (geology)
Porphyry is a variety of igneous rock consisting of large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass. The larger crystals are called phenocrysts...
rock with 5-10 mm orange-colored alkali feldspar
Alkali feldspar
The alkali feldspar group are those feldspar minerals rich in the alkali elements like potassium. The alkali feldspars include: anorthoclase, microcline, orthoclase and sanidine....
crystals. Most of the rounded hills on Fort Sill
Fort Sill
Fort Sill is a United States Army post near Lawton, Oklahoma, about 85 miles southwest of Oklahoma City.Today, Fort Sill remains the only active Army installation of all the forts on the South Plains built during the Indian Wars...
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
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
and hydrous gabbro
Gabbro
Gabbro refers to a large group of dark, coarse-grained, intrusive mafic igneous rocks chemically equivalent to basalt. The rocks are plutonic, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass....
exploited the boundary between the layered complex and the rhyolites. 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. Most are pink to brick red on fresh exposures. Some are equigranular
Equigranular
An equigranular material is composed chiefly of crystals of similar orders of magnitude to one another. Basalt and gabbro commonly exhibit an equigranular texture....
, others are porphyritic
Porphyry (geology)
Porphyry is a variety of igneous rock consisting of large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass. The larger crystals are called phenocrysts...
. Some have a small concentration of sodium-rich amphiboles
Amphibole
Amphibole is the name of an important group of generally dark-colored rock-forming inosilicate minerals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures.-Mineralogy:...
. The Mount Scott Granite is the most extensively exposed Wichita Granite. It forms the topographic feature from which it takes it name, and it is distributed throughout the northern half of the wildlife refuge. Dark rounded alkali feldspar
Alkali feldspar
The alkali feldspar group are those feldspar minerals rich in the alkali elements like potassium. The alkali feldspars include: anorthoclase, microcline, orthoclase and sanidine....
s, typically one centimeter or less in diameter, dominate this rock.
Relatively small and compositionally distinct plutons
Pluton
A pluton in geology is a body of intrusive igneous rock that crystallized from magma slowly cooling below the surface of the Earth. Plutons include batholiths, dikes, sills, laccoliths, lopoliths, and other igneous bodies...
, 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
Biotite is a common phyllosilicate mineral within the mica group, with the approximate chemical formula . More generally, it refers to the dark mica series, primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite; more aluminous endmembers...
, a mineral that forms in magmas
Magma
Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...
with elevated dissolved water. One of these bodies, the Mount Sheridan Gabbro, is exposed in roadcuts at Meers
Meers
Meers is a surname and may be:* Nelson Meers , Australian lawyer and Lord Mayor of Sydney* Nick Meers , English photographer* William Meers , English cricketerMeers may also be a place:* Meers, Oklahoma, USA...
and underlies the Mount Scott Granite on the north side of the wildlife refuge. Weathered gabbroic soils are thicker and support more vegitation than those generated on weathered granite
Grus (geology)
Grus is an accumulation of angular, coarse-grained fragments resulting from the granular disintegration of crystalline rocks generally in an arid or semiarid region. Grus sand, when cemented into a sandstone, will form an arkose....
, 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
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
and diabase
Diabase
Diabase or dolerite is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. In North American usage, the term diabase refers to the fresh rock, whilst elsewhere the term dolerite is used for the fresh rock and diabase refers to altered material...
dikes
Dike (geology)
A dike or dyke in geology is a type of sheet intrusion referring to any geologic body that cuts discordantly across* planar wall rock structures, such as bedding or foliation...
. 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
Oklahoma State Highway 49
State Highway 49 is a 30-mile long state highway in the U.S. state of Oklahoma. It runs from State Highway 54 in Kiowa County to Interstate 44 near Lawton. Part of the highway runs through the Wichita Mountains Wildlife Refuge; this portion of SH-49 carries no signage identifying it as such. It...
, just west of Interstate 44
Interstate 44
Interstate 44 is a major highway in the central United States. Its western terminus is in Wichita Falls, Texas at a concurrency with US 277, US 281 and US 287; its eastern terminus is at the Illinois state line on the Poplar Street Bridge over the Mississippi River in St...
. Following the cessation of magmatism, the region subsided and was inundated by a shallow sea, resulting in the deposition of detrital sediments followed by carbonates
Carbonate rock
Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite and dolostone, which is composed of the mineral dolomite .Calcite can be either dissolved by groundwater or precipitated by...
. The light-colored rocks exposed in the Slick Hills are lower Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
marine sediments.
During the Pennsylvanian
Pennsylvanian
The Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods of the Carboniferous Period. It lasted from roughly . As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain...
Period (330–290 million years ago) the region was subjected to intense pressure during the continental collision or orogeny
Orogeny
Orogeny refers to forces and events leading to a severe structural deformation of the Earth's crust due to the engagement of tectonic plates. Response to such engagement results in the formation of long tracts of highly deformed rock called orogens or orogenic belts...
which produced the Ouachita Mountains
Ouachita Mountains
The Ouachita Mountains are a mountain range in west central Arkansas and southeastern Oklahoma. The range's subterranean roots may extend as far as central Texas, or beyond it to the current location of the Marathon Uplift. Along with the Ozark Mountains, the Ouachita Mountains form the U.S...
to the east. This resulted in faulting and folding
Fold (geology)
The term fold is used in geology when one or a stack of originally flat and planar surfaces, such as sedimentary strata, are bent or curved as a result of permanent deformation. Synsedimentary folds are those due to slumping of sedimentary material before it is lithified. Folds in rocks vary in...
striking
Strike and dip
Strike and dip refer to the orientation or attitude of a geologic feature. The strike line of a bed, fault, or other planar feature is a line representing the intersection of that feature with a horizontal plane. On a geologic map, this is represented with a short straight line segment oriented...
along a WNW direction and includes the Arbuckle
Arbuckle Mountains
The Arbuckle Mountains are an ancient mountain range in south-central Oklahoma in the United States. The granite rocks of the Arbuckles date back to the Proterozoic Era some 1.4 billion years ago which were overlain by sediments during the Paleozoic Era. The range reaches a height of 1,412 feet...
and Wichita Mountains of southern Oklahoma and the Amarillo Uplift of the Texas Panhandle
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 rectangular area bordered by New Mexico to the west and Oklahoma to the north and east...
. Up to 20000 feet (6,096 m) of local uplift occurred during this time. This uplift locally created rugged mountains reduced by erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
to their present state largely during the Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
Period. Extensive weathering produced the tors of the Charon Gardens region and the "river" of boulder
Boulder
In geology, a boulder is a rock with grain size of usually no less than 256 mm diameter. While a boulder may be small enough to move or roll manually, others are extremely massive....
s that decends the west slope of Mount Scott. Likewise, weathering produced the bowling-ball sized boulders in the Permian-age 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
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
sediments buried the Wichita Mountains, preserving them from further weathering. Geologically recent erosion is removing these sediments, excavating these once buried fossil landforms.