The Elkhorn Mountains are a mountain range in southwestern Montana, part of the Rocky Mountains 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 Helena may refer to: People *Helena (given name), a given name (including a list of people and characters with the name) *Katri Helena (born 1945), Finnish singer *Helena, mother of Constantine I Places Greece * Helena (island) Guyana * ...

, Montana City, Townsend, Whitehall, 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 time) as a result of the Farallon tectonic plate subducting beneath western North America and allowing magma to rise to the surface. The Elkhorn Mountains Volcanics are extrusive rocks related to the plutonic 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, 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 Elkhorn is a census-designated place (CDP) in Jefferson County, Montana, United States, in the Elkhorn Mountains of the southwestern part of the state. As of the 2010 census it had a population of 10. The community is considered a ghost town, a ...

, now a ghost town, and gold at the

Golden Sunlight Mine The Golden Sunlight mine is an open pit gold mine in Jefferson County, Montana, northeast of Whitehall Whitehall is a road and area in the City of Westminster, Central London. The road forms the first part of the A3212 road from Trafalgar ...

near Whitehall, 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 seedlings growing into new lodgepole pine forests. The land has been used extensively in the past for gold and silver mining,

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 and wildlife management 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

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 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.

Climate

Tizer Basin is a SNOTEL weather station situated by Big Tizer Creek near Bullock Hill (Montana). , Tizer Basin has a

subalpine climate The subarctic climate (also called subpolar climate, or boreal climate) is a climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of an ocean, ge ...

( Köppen ''Dfc'').

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

Climate

See also

Notes

External links