Ouachita Mountains
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Ouachita Mountains |
The
Ouachita Mountains are a mountain range located 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.
The Ouachita (pronounced "wah-shi-tah") Mountains are fold mountains like the
Appalachian Mountains to the east. During the
Pennsylvanian part of the
Carboniferous period, about 300 million years ago, the coastline of the
Gulf of Mexico ran through the central parts of Arkansas. As the South American plate
drifted northward, a
subduction zone was created in this region. The South American
oceanic crust was forced underneath the less-dense North American
continental crust. Geologists call this collision the
Ouachita orogeny. 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. Due to 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, the Ouachitas run east and west rather than north and south. This unique formation has been known to cause confusion to pilots flying over the region. Also, Ouachitas are distinctive in that
volcanism,
metamorphism, and
intrusions are notably absent throughout most of the system.
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Vertical quartzite and slate strata along the eastern flank of the Ouachitas |
The Ouachitas are noted for
quartz crystal deposits around the
Mount Ida area and for
Arkansas novaculite whetstones.
The Ouachita Mountains contain the
Ouachita National Forest and
Hot Springs National Park as well as numerous state parks and scenic byways. The Ouachita Mountains also contain the
Ouachita National Recreation Trail, a 223 mile long hiking trail through the heart of the mountains. The trail runs from Talimena State Park in Oklahoma to Pinnacle Mountain State Park, near Little Rock, Arkansas. It is a well maintained, premier trail for hikers, backpackers, and mountain bikers (for only selected parts of the trail).
The
Battle of Devil's Backbone was fought here at the ridge of the same name in 1863.
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Geology of the Ouachita Mountains, from a rockhound's perspective.*
Friends of the Ouachita Trail (FoOT)
