Geology

Kentucky can be divided into three parts - the eastern mountains, the interior, and the Mississippi plains in the west. These large areas can be divided into several physiographic regions. The eastern end of the state is known as the Eastern Coal Field. The Appalachian Mountains extend into the state here and the highest point in Kentucky, Big Black Mountain, 4,145 feet above sea level, is here in Harlan county. The western end of this region is known as the Cumberland Plateau which extends west to the Pottsville Escarpment and the eastern Knobs, which divide eastern Kentucky from the rolling hills of the Bluegrass.

The eastern Kentucky coal field covers the eastern end of the state, stretching from the Appalachian Mountains westward across the Cumberland Plateau to the Pottsville Escarpment.

The Eastern Kentucky Coal Field is part of a larger physiographic region called the Cumberland Plateau (which extends from Pennsylvania to Alabama). The eastern edge of the Eastern Kentucky Coal Field (and Cumberland Plateau) is called the Pottsville or Cumberland Escarpment. This escarpment (in large part) is formed from resistant Pennsylvanian-age sandstones and conglomerates. The escarpment is stepped in south-central Kentucky because several thick, resistant sandstones are separated by less resistant shales. The manner in which the sandstones weather and are eroded along the escarpment results in sheer cliffs, steep-walled gorges, rock shelters, waterfalls, natural bridges and arches, caves, and some of the most scenic areas in Kentucky. Cumberland Falls State Resort Park, Red River Gorge and Natural Bridge State Resort Park are examples of some of these scenic areas along the escarpment.

Clifflines & Rock shelters

Nearly 3,000 miles of rocky cliffs wind their way through the Daniel Boone National Forest, providing an array of habitats for various plants and animals. Learn More...

Arches

The number, size, and variety of natural stone arches in the Daniel Boone National Forest contribute to its uniqueness. Learn More...

Caves

Caves are features found in Karst terrain. Karst areas are regions where layers of water soluble rock, such as Limestone, Dolomite, or Gypsum are found. These rocks are dissolved by groundwater and typically have caves and sinkholes. Learn more...

 

SAMPLE:

The George Washington and Jefferson National Forests are endowed with a variety of geologic resources of regional and national significance, in part, because the Forests span three physiographic provinces: the Blue Ridge, the Ridge and Valley, and the Appalachian Plateau.

UNUSUAL GEOLOGIC FEATURES

The variety of unusual landforms found on the ranger districts throughout the Forests can be sensed from the names of these features: Rainbow Rock, Jingling Rocks, Roaring Run, Dragons Tooth, Devils Garden, Bubbling Springs, Blowing Springs, Cockscomb rocks, Crabtree Falls, Dismal Falls, and Devils Marbleyard.

GLIMPSE THE ICE AGE FROM I-81

During the Ice Age, the climate in Virginia was colder. The upper slopes of mountains had many bare rock slopes. The intense freeze-and-thaw cracked open the sandstone bedrock and produced a jumble of car-sized blocks of rock. These block fields extended for miles along the upper slopes of many mountains. After the Ice Age, with the return to a warmer climate, the forest cover was gradually established over most of the barren block fields.
Today, several remnants of these Ice Age block fields survive on the Forests. Travelers on Interstate 81, between I-66 and I-64, can see these Ice Age block fields along the western slopes of Massanutten Mountain and the Blue Ridge.

SINKHOLES, CAVES AND DISAPPEARING STREAMS

The Forests include part of the limestone karst terrain (caves, sinkholes, and disappearing streams) for which Virginia and West Virginia are famous. Visitors to the Trout Pond recreation area on the Lee Ranger District can see several sinkholes, a disappearing stream, and the only natural lake in West Virginia.

THE MOUNTAINS THAT MOVED

Ancient giant landslides discovered on the Forests in the 1980s are the largest known in eastern North America. The landslides contain more than one billion cubic yards of rock, and extend more than 10 miles along Sinking Creek Mountain on the New Castle and Blacksburg Ranger Districts.

MODERN LANDSLIDES IN THE FOREST

Because the Forest’s watersheds are mainly mountainous watersheds, landslides are an important natural disturbance that plays a major role in flooding, sedimentation, and the functioning of riparian areas. Landslides are mass movements of soil and rock, such as, debris avalanches, debris slides, debris flows, slumps, rockslides, stream channel bank failures, etc. Infrequent storms with intense rainfall can trigger numerous landslides that drastically increase the destructive power of floods. The June 27, 1995 rainstorm on the Glenwood/Pedlar Ranger District triggered more than 40 landslides on the western slope of the Blue Ridge between Glasgow and Buena Vista. These landslides (debris avalanches, debris slides and debris flows) swept down the steep slopes, created temporary dams in streams channels, and sent thousands of tons of rock, mud, and woody debris into the streams, floodplain and alluvial fans outside the Forest boundary. Some “floods that emerged from the Forest were actually “debris flows, caused by landslides sweeping down flood-swollen channels or by failure of dams created by landslides that temporarily blocked flood-swollen channels.

Debris flows are a geologic hazard. To learn more about debris flows and geologic hazards, visit Debris Flow Hazards in the Blue Ridge.

Other storms that have triggered multiple landslides on the Forest include: June 17-18, 1949 storm on the Dry River RD; August 19-20, 1969 Hurricane Camille on the Pedlar RD; November 3-5, 1985 storm on the George Washington NF; July 29, 2001 storm on the Clinch RD. Road construction and other ground-disturbing activities may cause, or contribute to causing, landslides in the form of road cut-slope failures and fill-slope failures.

VOLCANIC FIRE AND GLACIAL ICE ON THE BLUE RIDGE

Much of the famous Blue Ridge Mountains in Virginia is administered by the Forests, but many people are unaware the Blue Ridge contains: remnants of volcanic explosions and lava flows that once erupted and buried part of southwestern Virginia; glacial deposits from a 500 million year old Ice Age; rhythmite, an unusual, maroon bedrock, preserving seasonal variations in ancient lakes and seas; the oldest rocks in Virginia (the Cranberry gneiss) -- over a billion years old. These features are on the Mount Rogers National Recreation Area.

GEOLOGY IN ACTION - STREAMS AND RIPARIAN AREAS

How are streams and riparian areas created in the mountains?
Do streams and riparian areas grow larger over time?
What three geologic factors affect the past, present, and future of streams and riparian areas?
Looking at a topographic map, can you find similarities in streams and riparian areas? Can you find differences? What controls the similarities and the differences?
What geologic resources are found along streams and riparian areas?
To explore these questions, visit Geology in Action - Streams and Riparian Areas.

A GREAT MOUNTAIN IN THE GREAT VALLEY

The Great Valley, part of the Ridge and Valley Province, extends over 1,200 miles from New York to Alabama. In Virginia, Massanutten Mountain rises 1,000 feet above the Great Valley and extends for 50 miles. The history of this mountain, from ancient sea floor to modern mountain, is told along the Massanutten Mountain Story Trail on the Lee Ranger District. Forest visitors can also stop at the Woodstock Observation Tower for a view of the Great Valley, including the Seven Bends of the North Fork Shenandoah River at the foot of Massanutten Mountain.

SILENT REMINDERS

The iron industry played a vital role in the industrialization of the United States and in the development of the U.S. economy and society. Much of the early history of the iron industry took place in Virginia. The remains of 11 iron furnaces and nearby mines in the George Washington and Jefferson National Forests in Virginia and West Virginia are silent reminders of a time when iron mines and furnaces operated along a belt that extended through the Appalachian Mountains from New York State to Alabama.

FOSSILS

Fossils found on the Forests include fossil plants and ripple marks and worm borrows in a 500 million year old beach. For more information about fossils on the Forest, visit Sea Shells in the Mountains, Fossils in the Forest.

For Additional Information Regarding this Resource Contact: Tom Collins (540) 265-5152





https://www.fs.usda.gov/detail/dbnf/landmanagement/resourcemanagement?cid=fsbdev3_032624