Grand Hogback

Last updated

Grand Hogback
Grand Hogback.JPG
Part of the Grand Hogback near New Castle, Colorado.
Highest point
Elevation 2,212 m (7,257 ft) [1]
Coordinates 39°37′07″N107°45′17″W / 39.61861°N 107.75472°W / 39.61861; -107.75472
Geography
USA Colorado relief location map.svg
Red triangle with thick white border.svg
Grand Hogback

The Grand Hogback is a 70-mile long, [2] curving, spine-like ridge in Western Colorado that extends from near McClure Pass in Pitkin County through Garfield County and then to near Meeker in Rio Blanco County. [3] The hogback is significant because it marks part of the boundary between the Colorado Plateau to the west and the Southern Rocky Mountains to the east. [4]

Contents

The elevation of the ridge ranges from 7,710 ft (2,350 m) to 9,194 ft (2,802 m). The hogback appears as a series of serrated ridges and is easily discernable from Google Maps and other aerial views. [4] It is visible from Interstate 70.

Gaps

Rivers have carved out several gaps in the hogback, the most notable being the one the Colorado River has carved out near New Castle, Colorado. Others include Harvey Gap and Rifle Gap, [5] both of which have been dammed to create reservoirs and state parks.

Geology

The Grand Hogback Monocline defines the eastern limit of the Uinta-Piceance Basin Uinta Piceance Basins geologic map.gif
The Grand Hogback Monocline defines the eastern limit of the Uinta-Piceance Basin

A monocline, the Grand Hogback is part of the Mesaverde Formation. The ridge formed towards the end of the Laramide orogeny during the middle to late Eocene. [3]

Related Research Articles

<span class="mw-page-title-main">New Castle, Colorado</span> Town in Garfield County, Colorado, United States

The Town of New Castle is a home rule municipality in Garfield County, Colorado, United States. The population was 4,923 at the 2020 census.

<span class="mw-page-title-main">Rifle, Colorado</span> City in Colorado, United States

Rifle is a home rule municipality in and the most populous community of Garfield County, Colorado, United States. The population was 10,437 at the 2020 census. Rifle is a regional center of the cattle ranching industry located along Interstate 70 and the Colorado River just east of the Roan Plateau, which dominates the western skyline of the town. The town was founded in 1882 by Abram Maxfield, and was incorporated in 1905 along Rifle Creek, near its mouth on the Colorado. The community takes its name from the creek.

<span class="mw-page-title-main">Front Range</span> Mountain range of the Southern Rocky Mountains of North America

The Front Range is a mountain range of the Southern Rocky Mountains of North America located in the central portion of the U.S. State of Colorado, and southeastern portion of the U.S. State of Wyoming. It is the first mountain range encountered as one goes westbound along the 40th parallel north across the Great Plains of North America.

<span class="mw-page-title-main">Green River (Colorado River tributary)</span> River in Wyoming, Utah, and Colorado, United States

The Green River, located in the western United States, is the chief tributary of the Colorado River. The watershed of the river, known as the Green River Basin, covers parts of the U.S. states of Wyoming, Utah, and Colorado. The Green River is 730 miles (1,170 km) long, beginning in the Wind River Mountains of Wyoming and flowing through Wyoming and Utah for most of its course, except for a short segment of 40 miles (64 km) in western Colorado. Much of the route traverses the arid Colorado Plateau, where the river has carved some of the most spectacular canyons in the United States. The Green is slightly smaller than Colorado when the two rivers merge but typically carries a larger load of silt. The average yearly mean flow of the river at Green River, Utah is 6,121 cubic feet (173.3 m3) per second.

<span class="mw-page-title-main">Dolores River</span> River in Colorado and Utah in the United States

The Dolores River is a tributary of the Colorado River, approximately 241 miles (388 km) long, in the U.S. states of Colorado and Utah. The river drains a rugged and arid region of the Colorado Plateau west of the San Juan Mountains. Its name derives from the Spanish El Rio de Nuestra Señora de Dolores, River of Our Lady of Sorrows. The river was explored and possibly named by Juan Maria Antonio Rivera during a 1765 expedition from Santa Fe.

<span class="mw-page-title-main">Colorado Plateau</span> Plateau in the Four Corners region of the southwestern United States

The Colorado Plateau, also known as the Colorado Plateau Province, is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. This province 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.

<span class="mw-page-title-main">Castle Peak (Colorado)</span> Mountain in the state of Colorado

Castle Peak is the ninth highest summit of the Rocky Mountains of North America and the U.S. state of Colorado. The prominent 14,279-foot (4352.2 m) fourteener is the highest summit of the Elk Mountains and the Maroon Bells-Snowmass Wilderness. The peak is located 11.6 miles (18.7 km) northeast by north of the Town of Crested Butte, Colorado, United States, on the drainage divide separating Gunnison National Forest and Gunnison County from White River National Forest and Pitkin County. The summit of Castle Peak is the highest point of both counties.

<span class="mw-page-title-main">Denver Basin</span> Geologic structural basin in the U.S.

The Denver Basin, variously referred to as the Julesburg Basin, Denver-Julesburg Basin, or the D-J Basin, is a geologic structural basin centered in eastern Colorado in the United States, but extending into southeast Wyoming, western Nebraska, and western Kansas. It underlies the Denver-Aurora Metropolitan Area on the eastern side of the Rocky Mountains.

<span class="mw-page-title-main">Milner Pass</span>

Milner Pass, elevation 10,759 ft (3,279 m) is a mountain pass in the Rocky Mountains of northern Colorado in the United States. It is located on the continental divide in the Front Range, within Rocky Mountain National Park, along the boundary between Larimer and Grand counties. The pass provides the passage over the continental divide for US 34, also known as Trail Ridge Road between Estes Park and Grand Lake. The pass is not, however, the high point on Trail Ridge Road, which crests at 12,183 ft (3,713 m) east of the pass within Rocky Mountain National Park. Along with the rest of Trail Ridge Road, the pass is generally closed in winter from the first heavy snow fall until the opening of the road around Memorial Day. The gentle pass divides the headwaters of the Cache la Poudre River and several creeks near the headwaters of the Colorado River to the west. The road near the pass provides a panoramic view of the Never Summer Mountains to the west.

<span class="mw-page-title-main">Dakota Hogback</span>

The Dakota Hogback is a long hogback ridge at the eastern fringe of the Rocky Mountains that extends north-south from southern Wyoming through Colorado and into northern New Mexico in the United States. The ridge is prominently visible as the first line of foothills along the edge of the Great Plains. It is generally faulted along its western side, and varies in height, with gaps in numerous locations where rivers exit the mountains. The ridge takes its name from the Dakota Formation, a formation with resistant sandstone beds that cap the ridge. The hogback was formed during the Laramide orogeny, approximately 50 million years ago, when the modern Rockies were created. The general uplift to the west created long faulting in the North American Plate, resulting in the creation of the hogback.

<span class="mw-page-title-main">Monocline</span>

A monocline is a step-like fold in rock strata consisting of a zone of steeper dip within an otherwise horizontal or gently dipping sequence.

<span class="mw-page-title-main">Wills Mountain</span>

Wills Mountain is a quartzite-capped ridge in the Ridge and Valley physiographic province of the Appalachian Mountains in Pennsylvania and Maryland, extending from near Bedford, Pennsylvania, to near Cumberland, Maryland. It is the northernmost of several mountain ridges included within the Wills Mountain Anticline.

<span class="mw-page-title-main">Hogback (geology)</span> Long, narrow ridge

In geology and geomorphology, a hogback or hog's back is a long, narrow ridge or a series of hills with a narrow crest and steep slopes of nearly equal inclination on both flanks. Typically, the term is restricted to a ridge created by the differential erosion of outcropping, steeply dipping, homoclinal, and typically sedimentary strata. One side of a hogback consists of the surface of a steeply dipping rock stratum called a dip slope. The other side is an erosion face that cuts through the dipping strata that comprises the hogback. The name "hogback" comes from the Hog's Back of the North Downs in Surrey, England, which refers to the landform's resemblance in outline to the back of a hog. The term is also sometimes applied to drumlins and, in Maine, to both eskers and ridges known as "horsebacks".

<span class="mw-page-title-main">Dakota Formation</span> Rock units in midwestern North America

The Dakota is a sedimentary geologic unit name of formation and group rank in Midwestern North America. The Dakota units are generally composed of sandstones, mudstones, clays, and shales deposited in the Mid-Cretaceous opening of the Western Interior Seaway. The usage of the name Dakota for this particular Albian-Cenomanian strata is exceptionally widespread; from British Columbia and Alberta to Montana and Wisconsin to Colorado and Kansas to Utah and Arizona. It is famous for producing massive colorful rock formations in the Rocky Mountains and the Great Plains of the United States, and for preserving both dinosaur footprints and early deciduous tree leaves.

<span class="mw-page-title-main">Navajo section</span>

The Navajo Section is a physiographic section of the larger Colorado Plateaus Province, which in turn is part of the larger Intermontane Plateaus physiographic Division.

<span class="mw-page-title-main">Homocline</span> Geological structure in which rock strata dip uniformly in a single direction

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.

Colorado is a geologic name applied to certain rocks of Cretaceous age in the North America, particularly in the western Great Plains. This name was originally applied to classify a group of specific marine formations of shale and chalk known for their importance in Eastern Colorado. The surface outcrop of this group produces distinctive landforms bordering the Great Plains and it is a significant feature of the subsurface of the Denver Basin and the Western Canadian Sedimentary Basin. These formations record important sequences of the Western Interior Seaway, and as the geology of this seaway was studied, this name came to be used in states beyond Colorado, but was later replaced in several of these states with more localized names.

<span class="mw-page-title-main">Dinosaur Ridge</span>

Dinosaur Ridge is a segment of the Dakota Hogback in the Morrison Fossil Area National Natural Landmark located in Jefferson County, Colorado, near the town of Morrison and just west of Denver.

The White River Plateau is a "broad structural dome" located north of Glenwood Springs, Colorado and north of the Colorado River. Also called the White River Uplift, the mountainous area is shown on maps as being roughly circular in area, occupying parts of the Colorado counties of Garfield and Rio Blanco, with small portions extending into Eagle and Routt counties. The Grand Hogback marks parts of the plateau's southern and western boundaries. The Flat Tops mountain range is part of the White River Plateau, and much of the plateau is located within the White River National Forest.

References

  1. "Grand Hogback". Geographic Names Information System . United States Geological Survey, United States Department of the Interior . Retrieved March 27, 2017.
  2. New Castle, Colorado. Living in New Castle. Retrieved: March 27, 2017.
  3. 1 2 Stracher, Glenn B.; et al. (2008). "Revisiting the South Cañon Number 1 Coal Mine fire during a geologic excursion from Denver to Glenwood Springs, Colorado". In Raynolds, Robert G. H. (ed.). Roaming the Rocky Mountains and Environs: Geological Field Trips. Geological Society of America. pp. 101–110. ISBN   9780813700106.
  4. 1 2 Colorado Mountain College. The Grand Hogback: Living life on the edge. Retrieved: March 27, 2017.
  5. Colorado Parks & Wildlife. Rifle Gap Archived August 17, 2015, at the Wayback Machine . Retrieved: March 27, 2017.