Front Range

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Front Range
Indian Peaks Wilderness.jpg
Front Range Peaks in the Indian Peaks Wilderness
Highest point
PeakGrays Peak
Elevation 14,278 ft (4,352 m)
Coordinates 39°38′02″N105°49′01″W / 39.63389°N 105.81694°W / 39.63389; -105.81694
Geography
Image Wpdms nasa topo front range.jpg
The Front Range (excluding the Laramie Mountains) is shown highlighted on a map of the western U.S.
Country United States
States
  • Colorado
  • Wyoming
Parent range Rocky Mountains

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. [1] It is the first mountain range encountered as one goes westbound along the 40th parallel north across the Great Plains of North America.

Contents

The Front Range runs north-south between Casper, Wyoming, and Pueblo, Colorado, and rises nearly 10,000 feet above the Great Plains. Longs Peak, Mount Blue Sky, and Pikes Peak are its most prominent peaks, visible from the Interstate 25 corridor. The area is a popular destination for mountain biking, hiking, climbing, and camping during the warmer months and for skiing and snowboarding during winter. Millions of years ago, the present-day Front Range was home to ancient mountain ranges, deserts, beaches, and even oceans. [2]

The name "Front Range" is also applied to the Front Range urban corridor, the populated region of Colorado and Wyoming just east of the mountain range and extending from Cheyenne, Wyoming south to Pueblo, Colorado. This urban corridor benefits from the weather-moderating effect of the Front Range mountains, which help block prevailing storms.

Geology

Pikes Peak and Garden of the Gods. Ppgog.JPG
Pikes Peak and Garden of the Gods.
Uplifted Lyons Sandstone slabs along the eastern edge of the Front Range Fountain Valley Trail (5974714678).jpg
Uplifted Lyons Sandstone slabs along the eastern edge of the Front Range

Pikes Peak Granite

About 1 billion years ago, a mass of magma rose to the surface through a much older mantle, cooling to form what is now known as the Precambrian Pikes Peak Granite. Over the next 500 million years, the granite eroded with no sedimentation forming over this first uplift, resulting in a local expression of the Great Unconformity. At about 500–300 million years ago, the region began to sink and sediments began to deposit in the newly formed accommodation space. Eroded granite produced sand particles that began to form strata, layers of sediment, in the sinking basin. Sedimentation would continue to take place until about 300 million years ago. [2] [3]

Fountain formation

Around 300 million years ago, the sinking suddenly reversed, and the sediment-covered granite began to uplift, giving rise to the Ancestral Rocky Mountains. Over the next 150 million years, during the uplift the mountains continued to erode and cover their flanks in their own sediment. Wind, gravity, rainwater, snow, and ice-melt supplied rivers that ultimately carved through the granite mountains and eventually led to their complete removal. The sediment from these mountains lies in the very red Fountain Formation today. Red Rocks Amphitheatre outside of Denver, Colorado, is set within the Fountain Formation. [2]

Lyons Sandstone

At 280 million years ago, sea levels were low and present-day Colorado was part of the super-continent Pangaea. Sand deserts covered most of the area, spreading as dunes seen in the rock record, known today as the Lyons Sandstone. These dunes appear to be cross-bedded and show various fossil footprints and leaf imprints in many of the strata making up the section. [2] Uplifted beds of Lyons Sandstone are found along the Front range and form the gateway to the Garden of the Gods. [3]

Lykins Formation

30 million years later, the sediment deposition was still taking place with the introduction of the Lykins Shale. This formation can be best attributed to its wavy layers of muddy limestone and signs of stromatolites that thrived in a tidal flat in present-day Colorado. 250 million years ago, the Ancestral Rockies were eroding away [3] while the shoreline was present during the break-up of Pangaea. This formation began right after Earth's largest extinction 251 million years ago at the PermianTriassic Boundary. Ninety percent of the planet's marine life became extinct and a great deal on land as well. [2]

Morrison Formation

After 100 million years of deposition, a new environment brought rise to a new formation, the sandstone Morrison Formation. The Morrison Formation contains some of the best fossils of the Late Jurassic. It is especially known for its sauropod tracks and sauropod bones, among other dinosaur fossils. As identified by the fossil record, the environment was filled with various types of vegetation such as ferns and Zamites . [2] While this time period boasts many types of plants, grass had not yet evolved. [2]

Dakota Sandstone

The Dakota Sandstone, which was deposited around 100 million years ago at the opening of the Cretaceous Western Interior Seaway from the Arctic to the Tropics, shows evidence of ferns and dinosaur tracks. Sheets of ripple marks can be seen on some of the strata, confirming advancing and retreating near-shore environments. [2] These Dakota Group sandstone beds are resistant to erosion and have uplifted to form the Dakota Hogback, a ridge between the mountains and the plains. [3]

Benton Group / Niobrara Formation

Over the next 35 million years, the Cretaceous seaway repeatedly widened as far as Utah and Wisconsin and narrowed to near closure. [4] With no mountains present at the time, the Colorado area was in the line of the deepest channel of the seaway; but being on the Transcontinental Arch, the Front Range areas was relatively shallow and was near the last land to submerge as the seaway opened. Shale and chalk were deposited over the area as Greenhorn of the Benton Group and the Niobrara Formation. Within these beds are found abundant marine fossils (ammonites and skeletons of fish and such marine reptiles as mosasaurs, plesiosaurs, and extinct species of sea turtles) along with rare dinosaur and bird remains. Today, the Fort Hays Limestone member forms flatirons or secondary hogbacks on the east slope of the Dakota Hogback. [5]

Pierre Shale

The non-chalky shales of the Pierre Formation formed in the final cycle of the seaway. At about 68 million years ago, the Front Range began to rise again due to the Laramide Orogeny in the western half of the state, draining from being at the bottom of a sea to land again, giving yield to another fossiliferous rock layer, the Denver Formation. [2]

Denver Formation

Front Range near Estes Park, Colorado (Mummy Mountain) Mmtn.JPG
Front Range near Estes Park, Colorado (Mummy Mountain)

The Denver Formation contains fossils of dinosaurs like Tyrannosaurus rex and Triceratops. While the forests of vegetation, dinosaurs, and other organisms thrived, their reign would come to an end at the Cretaceous–Paleogene boundary (which was formerly known as the K-T boundary). In an instant, millions of species were obliterated by a meteor impact in Mexico's Yucatán Peninsula. While this extinction led to the demise of the dinosaurs and other organisms, some life did prevail to repopulate the earth as it recovered from this tremendous disaster. The uplifted mountains continued to constantly erode and, by 40 million years ago, the region was once again buried in material eroded from the central mountains. [2]

Castle Rock Conglomerate

Suddenly, 37 million years ago, a great volcanic eruption took place in the Collegiate Range and covered the landscape in hot ash that instantly torched and consumed everything across the landscape. An entire lush environment was capped in a matter of minutes with 20 feet of extremely resistant rock, rhyolite. However, as seen before, life rebounds, and after a few million years mass floods cut through the rhyolite and eroded much of it as plants and animals began to recolonize the landscape. The mass flooding and erosion of the volcanic rock formed the Castle Rock Conglomerate that can be found in the Front Range. [2]

Quaternary deposits

Eventually, at about 10 million years ago, the Front Range began to rise up again and the resistant granite in the heart of the mountains thrust upwards and stood tall, while the weaker sediments deposited above it eroded away. As the Front Range rose, streams and recent (16,000 years ago) glaciations during the Quaternary age literally unburied the range by cutting through the weaker sediment and giving rise to the granitic peaks present today. [2] This was the last step in forming the present-day geologic sequence and history of today's Front Range. [2]

Mountains from westlands.jpg
The Front Range as viewed from Greenwood Village south of Denver, Mount Blue Sky is on the far right, in the clouds.

Prominent peaks

The Front Range includes the highest peaks along the eastern edge of the Rockies. The highest mountain peak in the Front Range is Grays Peak. Other notable mountains include Torreys Peak, Mount Blue Sky, Longs Peak, Pikes Peak, and Mount Bierstadt.

Longs Peak Longs peak.JPG
Longs Peak
Pikes Peak Pike's Peak4.jpg
Pikes Peak
Mount Blue Sky Mevans.JPG
Mount Blue Sky
The 20 Mountain Peaks of the Front Range With At Least 500 Meters of Topographic Prominence
Rank Mountain Peak Subrange Elevation Prominence Isolation
1 Grays Peak [6] NGS Front Range14,278 ft
4352 m
2,770 ft
844 m
25 mi
40.3 km
2 Mount Blue Sky NGS Front Range14,265 ft
4348 m
2,769 ft
844 m
9.79 mi
15.76 km
3 Longs Peak NGS Front Range14,259 ft
4346 m
2,940 ft
896 m
43.6 mi
70.2 km
4 Pikes Peak NGS Pikes Peak Massif 14,115 ft
4302 m
5,530 ft
1686 m
60.8 mi
97.8 km
5 Mount Silverheels NGS PB Front Range13,829 ft
4215 m
2,283 ft
696 m
5.48 mi
8.82 km
6Bald Mountain [7] PB Front Range13,690 ft
4173 m
2,099 ft
640 m
7.51 mi
12.09 km
7 Bard Peak [7] PB Front Range13,647 ft
4159 m
1,701 ft
518 m
5.43 mi
8.74 km
8 Hagues Peak NGS PB Mummy Range 13,573 ft
4137 m
2,420 ft
738 m
15.92 mi
25.6 km
9 North Arapaho Peak [7] PB Indian Peaks PB 13,508 ft
4117 m
1,665 ft
507 m
15.4 mi
24.8 km
10 Parry Peak [7] Front Range13,397 ft
4083 m
1,731 ft
528 m
9.46 mi
15.22 km
11 Mount Richthofen [7] PB Front Range12,945 ft
3946 m
2,680 ft
817 m
9.66 mi
15.54 km
12 Specimen Mountain [7] PB Front Range12,494 ft
3808 m
1,731 ft
528 m
4.86 mi
7.82 km
13 Bison Peak NGS PB Tarryall Mountains PB 12,432 ft
3789 m
2,451 ft
747 m
19.14 mi
30.8 km
14 Waugh Mountain [7] PB South Park Hills PB 11,716 ft
3571 m
2,330 ft
710 m
20 mi
32.2 km
15 Black Mountain NGS PB South Park Hills PB 11,649 ft
3551 m
2,234 ft
681 m
8.03 mi
12.92 km
16 Williams Peak NGS PB South Williams Fork Mountains PB 11,620 ft
3542 m
2,049 ft
625 m
10.79 mi
17.37 km
17Puma Peak [7] PB South Park Hills PB 11,575 ft
3528 m
2,260 ft
689 m
7.44 mi
11.97 km
18 Thirtynine Mile Mountain [7] PB South Park Hills PB 11,553 ft
3521 m
2,088 ft
636 m
10.61 mi
17.08 km
19 Twin Sisters Peaks [7] PB Front Range11,433 ft
3485 m
2,328 ft
710 m
4.36 mi
7.01 km
20 South Bald Mountain Laramie Mountains 11,007 ft
3355 m
1,844 ft
562 m
13.66 mi
22 km

Travel

The main interstate highways that run through the Front Range are Interstate 70, which crosses west of Denver, Colorado, and Interstate 80, which crosses near Laramie, Wyoming. U.S. Route 34 travels through the mountains near Loveland, Colorado, although this route is typically closed from October to May. [8] U.S. Route 24 travels through the southern Front Range west of Colorado Springs, eventually connecting with I-70 west of Vail, Colorado.

Along with the roads that run through the Front Range, the Union Pacific Railroad operates two rail lines through the mountains. The first Overland Route, transiting southern Wyoming, runs parallel to I-80 for much of its way. The second is the former Denver & Rio Grande Western Railroad Moffat Route, which runs parallel to the Colorado River and through the 6.5-mile-long Moffat Tunnel. Originally the Denver and Salt Lake Railway, the former Rio Grande is used for freight by both Union Pacific and BNSF, and it is also used by Amtrak's California Zephyr and Winter Park Express .

See also

Related Research Articles

<span class="mw-page-title-main">Geology of the Grand Canyon area</span> Aspect of geology

The geology of the Grand Canyon area includes one of the most complete and studied sequences of rock on Earth. The nearly 40 major sedimentary rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from about 200 million to nearly 2 billion years old. Most were deposited in warm, shallow seas and near ancient, long-gone sea shores in western North America. Both marine and terrestrial sediments are represented, including lithified sand dunes from an extinct desert. There are at least 14 known unconformities in the geologic record found in the Grand Canyon.

The exposed geology of the Bryce Canyon area in Utah shows a record of deposition that covers the last part of the Cretaceous Period and the first half of the Cenozoic era in that part of North America. The ancient depositional environment of the region around what is now Bryce Canyon National Park varied from the warm shallow sea in which the Dakota Sandstone and the Tropic Shale were deposited to the cool streams and lakes that contributed sediment to the colorful Claron Formation that dominates the park's amphitheaters.

<span class="mw-page-title-main">Geology of the Grand Teton area</span>

The geology of the Grand Teton area consists of some of the oldest rocks and one of the youngest mountain ranges in North America. The Teton Range, partly located in Grand Teton National Park, started to grow some 9 million years ago. An older feature, Jackson Hole, is a basin that sits aside the range.

<span class="mw-page-title-main">Geology of the Canyonlands area</span>

The geology of the park is the consequence of deposition, uplift and erosion. Island in the Sky is a mesa overlooking the Green River to the west and the Colorado River to the east, and separated from the Colorado Plateau by the "the neck". From the top of the mesa to the Honaker Trail Formation at the canyon river bottom, 150 million years of geologic stratum is exposed. Upheaval Dome consists of the Chinle Formation in the center and the Navajo Sandstone along the rim. The Cedar Mesa Sandstone comprised the Needles District. Canyons comprise the Maze District.

<span class="mw-page-title-main">Geology of the Capitol Reef area</span>

The exposed geology of the Capitol Reef area presents a record of mostly Mesozoic-aged sedimentation in an area of North America in and around Capitol Reef National Park, on the Colorado Plateau in southeastern Utah.

<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">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">Pikes Peak granite</span> Geological formation in Colorado, United States

Pikes Peak granite is a 1.08 billion year old Late-Precambrian geologic formation found in the central part of the Front Range of Colorado. It is a coarse-grained pink to light red syenogranite with minor gray monzogranite, and it has a distinctive brick-red appearance where it outcrops. The granite gets its name from the 14,115-foot (4,302 m) Pikes Peak, which is made up almost entirely of this rock.

<span class="mw-page-title-main">Geology of the Rocky Mountains</span>

The geology of the Rocky Mountains is that of a discontinuous series of mountain ranges with distinct geological origins. Collectively these make up the Rocky Mountains, a mountain system that stretches from Northern British Columbia through central New Mexico and which is part of the great mountain system known as the North American Cordillera.

<span class="mw-page-title-main">Fountain Formation</span> American geological formation

The Fountain Formation is a Pennsylvanian bedrock unit consisting primarily of conglomerate, sandstone, or arkose, in the states of Colorado and Wyoming in the United States, along the east side of the Front Range of the Rocky Mountains, and along the west edge of the Denver Basin.

<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">Laramie Formation</span> Geological formation in Colorado, US

The Laramie Formation is a geologic formation of the Late Cretaceous (Maastrichtian) age, named by Clarence King in 1876 for exposures in northeastern Colorado, in the United States. It was deposited on a coastal plain and in coastal swamps that flanked the Western Interior Seaway. It contains coal, clay and uranium deposits, as well as plant and animal fossils, including dinosaur remains.

<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">Dinosaur Ridge</span> Natural heritage site in Colorado, United States

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.

Prehistory of Colorado provides an overview of the activities that occurred prior to Colorado's recorded history. Colorado experienced cataclysmic geological events over billions of years, which shaped the land and resulted in diverse ecosystems. The ecosystems included several ice ages, tropical oceans, and a massive volcanic eruption. Then, ancient layers of earth rose to become the Rocky Mountains.

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

The Arapahoe Formation is a geological formation of latest Cretaceous (Maastrichtian) age that is present within the Denver Basin that underlies the Denver, Colorado, area. The formation includes fossil leaves and dinosaur remains, although none of the latter have yet been referred to a specific genus. It also includes aquifers that are important sources of water for the area.

<span class="mw-page-title-main">Geology of Wyoming</span>

The geology of Wyoming includes some of the oldest Archean rocks in North America, overlain by thick marine and terrestrial sediments formed during the Paleozoic, Mesozoic and Cenozoic, including oil, gas and coal deposits. Throughout its geologic history, Wyoming has been uplifted several times during the formation of the Rocky Mountains, which produced complicated faulting that traps hydrocarbons.

<span class="mw-page-title-main">Geology of Utah</span>

The geology of Utah, in the western United States, includes rocks formed at the edge of the proto-North American continent during the Precambrian. A shallow marine sedimentary environment covered the region for much of the Paleozoic and Mesozoic, followed by dryland conditions, volcanism, and the formation of the basin and range terrain in the Cenozoic.

<span class="mw-page-title-main">Geology of Colorado</span>

The bedrock under the U.S. State of Colorado was assembled from island arcs accreted onto the edge of the ancient Wyoming Craton. The Sonoma orogeny uplifted the ancestral Rocky Mountains in parallel with the diversification of multicellular life. Shallow seas covered the regions, followed by the uplift current Rocky Mountains and intense volcanic activity. Colorado has thick sedimentary sequences with oil, gas and coal deposits, as well as base metals and other minerals.

<span class="mw-page-title-main">Lytle Formation</span> Geologic formation in Colorado and New Mexico, US

The Lytle Formation or Lytle Sandstone is a geologic formation found in Wyoming, Colorado, and New Mexico.

References

  1. "GNIS Feature Search". Archived from the original on 2012-07-14. Retrieved 2010-05-13. |U.S. Geological Survey confirms that the Laramie Mountains(range) are the northern extent of the Front Range.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 Johnson, Kirk R.; et al. (2006). Ancient Denvers. Fulcrum Publishing. ISBN   978-1-55591-554-4.
  3. 1 2 3 4 Williams, Felice; Chronic, Halka (2014) [1980]. Roadside Geology of Colorado (3rd ed.). pp. 9–11, 46–49. ISBN   978-0878426096.
  4. R.J. Weimer (1984). J.S. Schlee (ed.). "Relation of unconformities, tectonics, and sea-level changes, Cretaceous of Western Interior, United States" (PDF). AAPG Memoir (Memoir 36, Interregional unconformities and hydrocarbon accumulation). American Association of Petroleum Geologists: 407. Retrieved March 21, 2021.
  5. Noblett, J.B. (2011). A Guide to the Geological History of the Pikes Peak Region, Colorado Springs (2nd ed.). Colorado Springs, Colorado: Colorado College. p. 43. (Benton Group is in current use in this location.)
  6. The summit of Grays Peak is the highest point on the Continental Divide of North America.
  7. 1 2 3 4 5 6 7 8 9 10 The elevation of this summit has been converted from the National Geodetic Vertical Datum of 1929 (NGVD 29) to the North American Vertical Datum of 1988 (NAVD 88). National Geodetic Survey Archived 2011-10-19 at the Wayback Machine
  8. "Road Status Report - Rocky Mountain National Park (U.S. National Park Service)". www.nps.gov. Archived from the original on 8 February 2019. Retrieved 8 January 2020.

Further reading