Ouachita Mountains
The Ouachita Mountains are a mountain range
Mountain range
A mountain range is a single, large mass consisting of a succession of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, direction, formation, and age; a component part of a mountain system or of a mountain chain...

 in west central
Western Arkansas
Western Arkansas is a region of the U.S. state of Arkansas. It can be roughly defined by Crawford County in the northwest, Van Buren County in the northeast, Dallas County in the southeast, and Sevier County in the southwest. Some notable towns there include Fort Smith, Van Buren, Clarksville,...

Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...

 and southeastern
Kiamichi country
Southeastern Oklahoma, also known by its official tourism designation, Kiamichi Country, encompasses the southeastern quarter of the state of Oklahoma. The term "Kiamichi Country" was coined by the Oklahoma Department of Tourism and Recreation as one of six travel destination regions within the...

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 range's subterranean roots may extend as far as central Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, or beyond it to the current location of the Marathon Uplift
Marathon Uplift
The Marathon Uplift is a Tertiary-age domal uplift, approximately in diameter, in southwest Texas. The Marathon Basin was created by erosion of Cretaceous and younger strata from the crest of the uplift...

. Along with the Ozark Mountains, the Ouachita Mountains form the U.S. Interior Highlands
U.S. Interior Highlands
The U.S. Interior Highlands is a mountainous region spanning eastern Oklahoma, western and northern Arkansas, southern Missouri, and the extreme southeast corner of Kansas. The name is designated by the United States Geological Survey to refer to the combined mountainous region of the Ozarks and...

, one of the few major mountainous regions between the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

 and the Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...

. The highest peak in the Ouachitas is Mount Magazine
Mount Magazine
Mount Magazine is the name commonly used for the tallest mountain in the state of Arkansas and is the site of Arkansas's newest state park. The mountain is a flat-topped plateau with a sandstone cap rimmed by precipitous rock cliffs...

 in west-central Arkansas which rises to 2753 feet (839.1 m).


The word Ouachita is composed of two Choctaw words: ouac, a buffalo, and chito, large. It means the country of large buffaloes, numerous herds of those animals having formerly covered the prairies of Ouachita.

Geology and physiography

The Ouachita Mountains are a physiographic section
Physiographic regions of the world
The physiographic regions of the world are a means of defining the Earth's landforms into distinct regions based upon classic 1916 three-tiered approach defining divisions, provinces, and sections...

 of the larger Ouachita province (which includes both the Ouachita Mountains and the Arkansas Valley), which in turn is part of the larger Interior Highlands
U.S. Interior Highlands
The U.S. Interior Highlands is a mountainous region spanning eastern Oklahoma, western and northern Arkansas, southern Missouri, and the extreme southeast corner of Kansas. The name is designated by the United States Geological Survey to refer to the combined mountainous region of the Ozarks and...

 physiographic division.

The Ouachita Mountains are fold mountain
Fold mountain
Fold mountains are mountains formed mainly by the effects of folding on layers within the upper part of the Earth's crust. In the time before either plate tectonic theory developed, or the internal architecture of thrust belts became well understood, the term was used for most mountain belts, such...

s like the Appalachian Mountains to the east, and were originally part of that range. During the 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...

 part of the Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

 period, about 300 million years ago, the coastline of the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...

 ran through the central parts of Arkansas. As the South American plate
South American Plate
The South American Plate is a continental tectonic plate which includes the continent of South America and also a sizeable region of the Atlantic Ocean seabed extending eastward to the Mid-Atlantic Ridge....

Continental drift
Continental drift is the movement of the Earth's continents relative to each other. The hypothesis that continents 'drift' was first put forward by Abraham Ortelius in 1596 and was fully developed by Alfred Wegener in 1912...

 northward, a subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...

 zone was created in this region. The South American oceanic crust
Oceanic crust
Oceanic crust is the part of Earth's lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium...

 was forced underneath the less-dense North American continental crust
Continental crust
The continental crust is the layer of igneous, sedimentary, and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called sial due to more felsic, or granitic, bulk composition, which lies in...

. Geologists call this collision the Ouachita orogeny
Ouachita orogeny
The Ouachita orogeny was a mountain building event that resulted in the folding and faulting of strata currently exposed in the Ouachita Mountains...

. The collision buckled the continental crust, producing the fold mountains we call the Ouachitas. At one time the Ouachita Mountains were very similar in height to the current elevations of the Rocky Mountains. Because of the Ouachitas' age, the craggy tops have eroded away, leaving the low formations that used to be the heart of the mountains.

Unlike most other mountain ranges in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, the Ouachitas run east and west rather than north and south. Also, the Ouachitas are distinctive in that volcanism
Volcanism is the phenomenon connected with volcanoes and volcanic activity. It includes all phenomena resulting from and causing magma within the crust or mantle of a planet to rise through the crust and form volcanic rocks on the surface....

, metamorphism
Metamorphism is the solid-state recrystallization of pre-existing rocks due to changes in physical and chemical conditions, primarily heat, pressure, and the introduction of chemically active fluids. Mineralogical, chemical and crystallographic changes can occur during this process...

, and intrusions are notably absent throughout most of the system.

The Ouachitas are noted for quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...

 crystal deposits around the Mount Ida
Mount Ida, Arkansas
Mount Ida is a city in Montgomery County, Arkansas, United States. The population was 981 at the 2000 census. The city is the county seat of Montgomery County. It is known as the quartz crystal capital of the U.S...

 area and for renowned Arkansas novaculite
Novaculite is a form of chert or flint found in the Ouachita Mountains of Arkansas and Oklahoma and in the Marathon Uplift of Texas. Novaculite is considered to be highly siliceous sediments and may be a product of the low-grade metamorphism of chert beds...

Sharpening stone
Sharpening stones, water stones or whetstones are used to grind and hone the edges of steel tools and implements. Examples of items that may be sharpened with a sharpening stone include scissors, scythes, knives, razors and tools such as chisels, hand scrapers and plane blades...

s. This quartz was formed during the Ouachita orogeny, as folded rocks cracked and allowed fluids from deep in the Earth to fill the cracks.

The Ouachita Mountain area of Arkansas is dominated by 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...

 through Pennsylvanian clastic sediments, with the lower Collier formation in the core of the range and the Atoka formation on the flanks. The Atoka Formation, formed in the Pennsylvanian Period, is a sequence of marine, mostly tan to gray silty 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 and grayish-black 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...

s. Some rare calcareous
Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...

 beds and siliceous shales are known. The Collier sequence is composed of gray to black, lustrous shale containing occasional thin beds of dense, black, and intensely fractured chert
Chert is a fine-grained silica-rich microcrystalline, cryptocrystalline or microfibrous sedimentary rock that may contain small fossils. It varies greatly in color , but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements...

. An interval of bluish-gray, dense to spary, thin-bedded limestone
Limestone 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....

 may be present. Near its top, the limestone is conglomeratic
Conglomerate (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...

 and pelletoidal, in part, with pebbles and cobbles of limestone, chert, meta-arkose
Arkose is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar. Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose....

, and quartz. It was formed during the Late Cambrian.


The mountains are known to contain at least 15 endemic plant species (i.e. plants that occur nowhere else). These include Sabatia arkansana
Sabatia arkansana
Sabatia arkansana, commonly known as Pelton’s rose gentian, is an herbaceous annual in the gentian family. It was discovered in 2001 in several glades of the Ouachita Mountains in Saline County, Arkansas by John Pelton, a retired mechanic turned amateur photographer and naturalist...

, Valerianella nuttallii
Valerianella nuttallii
Nuttal's cornsalad is a small dicot annual plant of the family Valerianaceae....

, Liatris compacta
Liatris compacta
Liatris compacta, sometimes called Arkansas gayfeather, is a herbaceous plant species in the aster family Asteraceae and genus Liatris. It is native to west-central Arkansas in the United States, where it is found growing in habitats such as rocky ridges, bluffs, hillsides, weathered sandstone, and...

and Quercus acerifolia
Quercus acerifolia
Quercus acerifolia is a species of plant in the Fagaceae family. It is endemic to the United States. It is threatened by habitat loss.-Source:* Hess, W.J. 1998. . Downloaded on 23 August 2007....



The Ouachita Mountains contain the Ouachita National Forest
Ouachita National Forest
The Ouachita National Forest is a National Forest that lies in the western portion of Arkansas and portions of eastern Oklahoma.-History:The Ouachita National Forest is the oldest National Forest in the southern United States. The Forest encompasses , including most of the scenic Ouachita Mountains...

, Hot Springs National Park
Hot Springs National Park
Established from Hot Springs Reservation, Hot Springs National Park is a United States National Park in central Arkansas adjacent to the city of Hot Springs. Hot Springs Reservation was initially created by an act of the United States Congress on April 20, 1832, and the area was made a national...

 and Lake Ouachita
Lake Ouachita
Lake Ouachita is a reservoir created by the damming of the Ouachita River by Blakely Mountain Dam . The lake is located near Hot Springs, Arkansas. Lake Ouachita is the largest lake completely in Arkansas, as the larger Bull Shoals Lake extends into Missouri. Lake Ouachita has over of shoreline...

, as well as numerous state parks and scenic byways. They also contain the Ouachita National Recreation Trail
Ouachita National Recreation Trail
Ouachita National Recreation Trail is a long, continuous hiking trail through the Ouachita Mountainsof Oklahoma and Arkansas.The trail is primarily a hiking and backpacking trail, but about 2/3 of the trail are available to mountain bikers....

, a 223 miles (358.9 km) hiking trail through the heart of the mountains. The trail runs from Talimena State Park in Oklahoma to Pinnacle Mountain State Park
Pinnacle Mountain State Park
Pinnacle Mountain State Park is located just northwest of Little Rock, Arkansas, USA, in the foothills of the Ouachita Mountains near Natural Steps, Arkansas on Arkansas Highway 300. The primary natural feature of the park is Pinnacle Mountain, elevation , which rises steeply above the Arkansas...

 near Little Rock, Arkansas
Little Rock, Arkansas
Little Rock is the capital and the largest city of the U.S. state of Arkansas. The Metropolitan Statistical Area had a population of 699,757 people in the 2010 census...

. It is a well maintained, premier trail for hikers, backpackers, and mountain bikers (for only selected parts of the trail).

The Talimena Scenic Byway begins at Mena, Arkansas
Mena, Arkansas
Mena is a city in Polk County, Arkansas, United States. It is also the county seat of Polk County.It was founded by Arthur Edward Stilwell during the building of the Kansas City, Pittsburg and Gulf Railroad . It was Stilwell who decided Mena would be the name of this new town along the route to...

, and traverses 54 miles (86.9 km) of Winding Stair and Rich Mountains, long narrow east-west ridges which extend into Oklahoma. Rich Mountain reaches an elevation of 2681 feet (817.2 m) in Arkansas near the Oklahoma border. The 2-lane winding road is similar in routing, construction, and scenery to the Blue Ridge Parkway
Blue Ridge Parkway
The Blue Ridge Parkway is a National Parkway and All-American Road in the United States, noted for its scenic beauty. It runs for 469 miles , mostly along the famous Blue Ridge, a major mountain chain that is part of the Appalachian Mountains...

 of the Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...



The mountains were home to the Ouachita tribe
Ouachita tribe
The Ouachita are a Native American tribe from northeastern Louisiana along the Ouachita River.-History:The Ouachita were loosely affiliated with the Caddo Confederacy. Their traditional homelands were the lower reaches of the Ouachita River and along the Black River...

, for which they were named. Later French explorers translated the name to its present spelling. The first recorded exploration was in 1541 by Hernando de Soto. Later, in 1804, President Jefferson
Thomas Jefferson
Thomas Jefferson was the principal author of the United States Declaration of Independence and the Statute of Virginia for Religious Freedom , the third President of the United States and founder of the University of Virginia...

 sent William Dunbar and Dr. George Hunter to the area after the Louisiana Purchase
Louisiana Purchase
The Louisiana Purchase was the acquisition by the United States of America of of France's claim to the territory of Louisiana in 1803. The U.S...

. Hot Springs National Park
Hot Springs National Park
Established from Hot Springs Reservation, Hot Springs National Park is a United States National Park in central Arkansas adjacent to the city of Hot Springs. Hot Springs Reservation was initially created by an act of the United States Congress on April 20, 1832, and the area was made a national...

 became one of the nation's first parks in 1832. The Battle of Devil's Backbone
Battle of Devil's Backbone
The Battle of Devil's Backbone was a land battle of the American Civil War on September 1, 1863 in Sebastian County, Arkansas....

 was fought here at the ridge of the same name in 1863. In August 1990, the U.S. Forest Service discontinued clearcutting
Clearcutting, or clearfelling, is a controversial forestry/logging practice in which most or all trees in an area are uniformly cut down. Clearcutting, along with shelterwood and seed tree harvests, is used by foresters to create certain types of forest ecosystems and to promote select species that...

as the primary tool for harvesting and regenerating short leaf, pine and hardwood forests in the Ouachita National Forest.

Further reading

External links

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