The Elkhorn Mountains are a

mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have arise ...

in southwestern

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

, part of the

Rocky Mountains The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...

and are roughly 300,000 acres (1200 km²) in size. It is an inactive volcanic mountain range with the highest point being Crow Peak at , right next to Elkhorn Peak, . The range is surrounded by the cities of Helena, Montana City,

Townsend Townsend (pronounced tounʹ-zənd) or Townshend may refer to: Places United States *Camp Townsend, National Guard training base in Peekskill, New York *Townsend, Delaware *Townsend, Georgia *Townsend, Massachusetts, a New England town ** Townsend ...

Whitehall Whitehall is a road and area in the City of Westminster, Central London. The road forms the first part of the A roads in Zone 3 of the Great Britain numbering scheme, A3212 road from Trafalgar Square to Chelsea, London, Chelsea. It is the main ...

, and

Boulder In geology, a boulder (or rarely bowlder) is a rock fragment with size greater than in diameter. Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive. In c ...

and is part of the

Helena National Forest Helena National Forest is located in west-central Montana, in the United States. Covering , the forest is broken into several separate sections. The eastern regions are dominated by the Big Belt Mountains, and are the location of the Gates of the ...

in Montana's Jefferson County.

Geology

The rocks of the Elkhorns were formed about 74 to 81 million years ago (

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

time) as a result of the Farallon tectonic plate subducting beneath western North America and allowing

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

to rise to the surface. The Elkhorn Mountains Volcanics are

extrusive Extrusive rock refers to the mode of igneous volcanic rock formation in which hot magma from inside the Earth flows out (extrudes) onto the surface as lava or explodes violently into the atmosphere to fall back as pyroclastics or tuff. In contras ...

rocks related to the

plutonic Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form '' intrusions'', such as batholiths, dikes, sills, laccoliths, and volcanic necks.Intrusive RocksIntrusive rocks accessdate: March ...

granites of the

Boulder Batholith The Boulder Batholith is a relatively small batholith in southwestern Montana, United States, exposed at the surface as granite (more specifically quartz monzonite) and serving as the host rock for rich mineralized deposits at Butte and other loc ...

. Volcanic flows,

lahar A lahar (, from jv, ꦮ꧀ꦭꦲꦂ) is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley. Lahars are extreme ...

s, and ash falls from sources in the Elkhorn Mountains reach as far as

Choteau, Montana Choteau is a city in and the county seat of Teton County, Montana, United States. It lies along U.S. Routes 89 and 287, (the latter terminating at the former in this city) approximately east of the Rocky Mountains, near Flathead National F ...

, but the thickest deposits lie within a radius of about from the Elkhorns. The volcanics probably originally covered an area of about . Mineral deposits associated with the Elkhorn Mountains Volcanics include those mined at Elkhorn, Montana, now a ghost town, and gold at the Golden Sunlight Mine near

, which is associated with a breccia pipe in the volcanics. The mountain range seen today is related to regional structural uplift dating mostly to

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

time.

The Land

forest fire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of Combustibility and flammability, combustible vegetation. Depending on the type of vegetation present, a wildfire ...

in 1988 burned 47,000 acres (190 km²) of the mountain range, leaving carpets of

seedling A seedling is a young sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle (embryonic root), the hypocotyl (embry ...

s growing into new

lodgepole pine ''Pinus contorta'', with the common names lodgepole pine and shore pine, and also known as twisted pine, and contorta pine, is a common tree in western North America. It is common near the ocean shore and in dry montane forests to the subalpine, ...

forests. The land has been used extensively in the past for

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

and

silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...

logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. Logging is the beginning of a supply chain ...

, and

open range In the Western United States and Canada, open range is rangeland where cattle roam freely regardless of land ownership. Where there are "open range" laws, those wanting to keep animals off their property must erect a fence to keep animals out; th ...

grazing, leaving a noticeable impact; most notably the abandoned

mining town A mining community, also known as a mining town or a mining camp, is a community that houses miners. Mining communities are usually created around a mine or a quarry. Historic mining communities Australia * Ballarat, Victoria * Bendigo, ...

of Elkhorn. Recently with efforts conducted by the

BLM BLM most commonly refers to: * Black Lives Matter, an international anti-racism movement and organization * Bureau of Land Management, a U.S. federal government agency BLM may also refer to: Organizations * BLM (law firm), United Kingdom and ...

, Montana FWP and

, new

conservation Conservation is the preservation or efficient use of resources, or the conservation of various quantities under physical laws. Conservation may also refer to: Environment and natural resources * Nature conservation, the protection and manageme ...

and

wildlife management Wildlife management is the management process influencing interactions among and between wildlife, its habitats and people to achieve predefined impacts. It attempts to balance the needs of wildlife with the needs of people using the best availabl ...

plans have been put into place including

big horn sheep The bighorn sheep (''Ovis canadensis'') is a species of Ovis, sheep native to North America. It is named for its large Horn (anatomy), horns. A pair of horns might weigh up to ; the sheep typically weigh up to . Recent genetic testing indicates ...

reintroduction and the

westslope cutthroat trout The westslope cutthroat trout (''Oncorhynchus clarkii lewisi''), also known as the black-spotted trout, common cutthroat trout and red-throated trout is a subspecies of the cutthroat trout (''Oncorhynchus clarkii'') and is a freshwater fish in t ...

restoration Restoration is the act of restoring something to its original state and may refer to: * Conservation and restoration of cultural heritage ** Audio restoration ** Film restoration ** Image restoration ** Textile restoration * Restoration ecology ...

program. Management of the 2000+

elk The elk (''Cervus canadensis''), also known as the wapiti, is one of the largest species within the deer family, Cervidae, and one of the largest terrestrial mammals in its native range of North America and Central and East Asia. The common ...

herd in the area and the suppression of

noxious weeds A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...

is also an ongoing task. Despite the impacts of mining, around 100,000 acres of the Elkhorns were still roadless in 1992; this included 85,000 acres of roadless National Forest land as well as adjacent BLM, state and private lands. Congress designated 175,000 acres of the range as the "Elkhorns Wildlife Management Area," and one of Montana's most productive elk herds inhabits the range. Because the Elkhorns are higher in elevation than the nearby section of the

Continental Divide A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not ...

, they catch more moisture than do most other ranges east of the Divide. For this reason, the Elkhorns are especially diverse, with 148 documented vertebrate species.

Notes

External links

Geology of the Elkhorn Mountains VolcanicsElkhorn Wildlife Management Unit Elkhorn Mountain Endurance Runs
{{Authority control Mountain ranges of Montana Ranges of the Rocky Mountains Geology of Montana Landforms of Jefferson County, Montana Helena National Forest

Geology

The Land

See also

Notes

External links