A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks.
The geology of the Appalachians dates back more than 1.2 billion years to the Mesoproterozoic era when two continental cratons collided to form the supercontinent Rodinia, 500 million years prior to the development of the range during the formation of Pangea. The rocks exposed in today's Appalachian Mountains reveal elongate belts of folded and thrust faulted marine sedimentary rocks, volcanic rocks, and slivers of ancient ocean floor—strong evidences that these rocks were deformed during plate collision. The birth of the Appalachian ranges marks the first of several mountain building plate collisions that culminated in the construction of Pangea with the Appalachians and neighboring Anti-Atlas mountains near the center. These mountain ranges likely once reached elevations similar to those of the Alps and the Rocky Mountains before they were eroded.
The Cumberland Plateau is the southern part of the Appalachian Plateau in the Appalachian Mountains of the United States. It includes much of eastern Kentucky and Tennessee, and portions of northern Alabama and northwest Georgia. The terms "Allegheny Plateau" and the "Cumberland Plateau" both refer to the dissected plateau lands lying west of the main Appalachian Mountains. The terms stem from historical usage rather than geological difference, so there is no strict dividing line between the two. Two major rivers share the names of the plateaus, with the Allegheny River rising in the Allegheny Plateau and the Cumberland River rising in the Cumberland Plateau in Harlan County, Kentucky.
The Ridge-and-Valley Appalachians, also called the Ridge and Valley Province or the Valley and Ridge Appalachians, are a physiographic province of the larger Appalachian Highlands division. The physiographic province is divided into three sections: the Hudson Valley, the Central, and the Tennessee.
The Colorado Plateau is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. This plateau covers an area of 336,700 km2 (130,000 mi2) within western Colorado, northwestern New Mexico, southern and eastern Utah, northern Arizona, and a tiny fraction in the extreme southeast of Nevada. About 90% of the area is drained by the Colorado River and its main tributaries: the Green, San Juan, and Little Colorado. Most of the remainder of the plateau is drained by the Rio Grande and its tributaries.
The Cumberland Gap is a pass in the eastern United States through the long ridge of the Cumberland Mountains, within the Appalachian Mountains and near the tripoint of Kentucky, Virginia, and Tennessee. At an elevation of 1,631 feet (497 m) above sea level, it is famous in American colonial history for its role as a key passageway through the lower central Appalachians.
In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the location where the curvature is greatest, and the limbs are the sides of the fold that dip away from the hinge. Anticlines can be recognized and differentiated from antiforms by a sequence of rock layers that become progressively older toward the center of the fold. Therefore, if age relationships between various rock strata are unknown, the term antiform should be used.
The Potomac Highlands of West Virginia centers on five West Virginian counties in the upper Potomac River watershed in the western portion of the state's Eastern Panhandle, bordering Maryland and Virginia. Because of geographical proximity, similar topography and landscapes, and shared culture and history, the Potomac Highlands region is also considered to include Pocahontas, Randolph, and Tucker counties, even though they are in the Monongahela River or New River watersheds and not the Potomac River watershed.
Frozen Head State Park and Natural Area is a state park in Morgan County, Tennessee, in the southeastern United States. The park, situated in the Crab Orchard Mountains between the city of Wartburg and the community of Petros, contains some of the highest mountains in Tennessee west of the Blue Ridge Mountains.
The Tennessee Valley Divide is the boundary of the drainage basin of the Tennessee River and its tributaries.
Sharp's Ridge is a steep ridge in Knoxville, Tennessee, north of the city's downtown. A 111-acre (45 ha) area of the 7-mile (11 km) ridge is maintained as Sharp's Ridge Memorial Park, a city park dedicated to the honor of the area's war veterans. The ridge also is the site of a transmitting antenna farm that serves most of Knoxville's broadcasters. The highest ground point on the ridge is an abandoned fire tower located at 1,391 feet (424 m) above mean sea level. The ridge itself averages 200 to 300 feet above the surrounding valley floor, allowing panoramic views of the Great Smoky Mountains and adjacent ranges to the east and the Cumberland Plateau and Cumberland Mountains to the west.
North Fork Mountain is a quartzite-capped mountain ridge in the Ridge and Valley physiographic province of the Allegheny Mountains, also known as the High Alleghenies or Potomac Highlands, of eastern West Virginia. Kile Knob, at 4,588 feet, is the mountain's highest point, and Panther Knob and Pike Knob are nearly as high.
Brush Mountain is a stratigraphic ridge in the Appalachian Mountains of central Pennsylvania, United States, lying east of the Allegheny Front and west of Tussey Mountain. It runs along the southeast side of the Little Juniata River and forms a horseshoe around Sinking Run, and is the westernmost ridge in its section of the Ridge-and-valley Appalachians. The western ridge line separates the Logan Valley from the Sinking Valley.
Bedford County, Pennsylvania is situated along the western border of the Ridge and Valley physiographic province, which is characterized by folded and faulted sedimentary rocks of early to middle Paleozoic age. The northwestern border of the county is approximately at the Allegheny Front, a geological boundary between the Ridge and Valley Province and the Allegheny Plateau.
The San Gabriel Fault is a geological fault in Los Angeles County, California, running about 87 miles (140 km) southeastward from the Ridge Basin in the Sierra Pelona-San Emigdio Mountains juncture area to the western San Gabriel Mountains that forms their southwestern face near Sunland and the northeastern San Fernando Valley, and then on the south flank to the southeastern part of the San Gabriel range.
In structural geology, a homocline or homoclinal structure, is a geological structure in which the layers of a sequence of rock strata, either sedimentary or igneous, dip uniformly in a single direction having the same general inclination in terms of direction and angle. A homocline can be associated with either one limb of a fold, the edges of a dome, the coast-ward tilted strata underlying a coastal plain, slice of thrust fault, or a tilted fault block. When the homoclinal strata consists of alternating layers of rock that vary hardness and resistance to erosion, their erosion produces either cuestas, homoclinal ridges, or hogbacks depending on the angle of dip of the strata. On a topographic map, the landfroms associated with homoclines exhibit nearly parallel elevation contour lines that show a steady change in elevation in a given direction. In the subsurface, they characterize by parallel structural contour lines.
The U.S. state of Tennessee is geographically diverse, with varying terrains and several distinct physiographic regions. Its landforms range from the Blue Ridge Mountains in the eastern part of the state to flat and fertile plains along the Mississippi River. The state is geographically, legally, culturally, and economically divided into three Grand Divisions: East Tennessee, Middle Tennessee, and West Tennessee.
The Mareuil Anticline, also called Mareuil-Meyssac Anticline, is a structural high within the sedimentary sequence of the northeastern Aquitaine Basin. The northwest-southeast trending anticline was caused by tectonic movements probably starting in the Upper Cretaceous.
The Kimberling Creek Cluster is a region in the Jefferson National Forest recognized by The Wilderness Society for its diversity of habitats extending along parts of Brushy and Hogback Mountains. Kimberling Creek, with headwaters in the cluster, flows into Big Walker Creek, a tributary of the New River.
