Ouachita Mountains - Definition and Overview

The Ouachita Mountains are a mountain range located in Arkansas and Oklahoma. The range may once have extended into central Texas, or even as far as the current location of the Marathon Uplift.

Ouachita Mountains

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 to the Rocky Mountains, but due to their 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.

The Ouachita Mountains contain the Ozark National Forest and Hot Springs National Park as well as numerous state parks and scenic byways.

External link

• Geology of the Ouachita Mountains, from a rockhound's perspective. (http://rockhoundingar.com/geology/ouamtns.html)

Regions of Arkansas
Ozarks | Ouachita Mountains | Mississippi Alluvial Plain | Crowley's Ridge | Arkansas River Valley
Little Rock metropolitan area | Memphis metropolitan area
Largest Cities
Benton | Bentonville | Blytheville | Conway | El Dorado | Fayetteville | Fort Smith | Hot Springs | Jacksonville | Jonesboro | Little Rock | North Little Rock | Paragould | Pine Bluff | Rogers | Russellville | Searcy | Sherwood | Springdale | Texarkana | Van Buren
Counties
Arkansas | Ashley | Baxter | Benton | Boone | Bradley | Calhoun | Carroll | Chicot | Clark | Clay | Cleburne | Cleveland | Columbia | Conway | Craighead | Crawford | Crittenden | Cross | Dallas | Desha | Drew | Faulkner | Franklin | Fulton | Garland | Grant | Greene | Hempstead | Hot Spring | Howard | Independence | Izard | Jackson | Jefferson | Johnson | Lafayette | Lawrence | Lee | Lincoln | Little River | Logan | Lonoke | Madison | Marion | Miller | Mississippi | Monroe | Montgomery | Nevada | Newton | Ouachita | Perry | Phillips | Pike | Poinsett | Polk | Pope | Prairie | Pulaski | Randolph | Saline | Scott | Searcy | Sebastian, | Sevier | Sharp | St. Francis | Stone | Union | Van Buren | Washington | White | Woodruff | Yell