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The Beaverhead impact structure is the 2nd largest
Aerial Exploration of the Beaverhead crater
Proterozoic impact craters Impact craters of the United States Landforms of Idaho Landforms of Beaverhead County, Montana {{US-geology-stub
The Beaverhead impact structure is the 2nd largest impact structure
An impact structure is a generally circular or craterlike geologic structure of deformed bedrock or sediment produced by impact on a planetary surface, whatever the stage of erosion of the structure. In contrast, an impact crater is the surface ...
within the U.S.
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territor ...
It lies within the states of Idaho
Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and W ...
and Montana
Montana () is a U.S. state, state in the Mountain states, Mountain West List of regions of the United States#Census Bureau-designated regions and divisions, division of the Western United States. It is bordered by Idaho to the west, North ...
. Estimated at in diameter, it is the 9th largest impact crater on Earth.
With an estimated age of 600 million years (Neoproterozoic
The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago.
It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is ...
), the impact's original shatter cone
Shatter cones are rare geological features that are only known to form in the bedrock beneath meteorite impact craters or underground nuclear explosions. They are evidence that the rock has been subjected to a shock with pressures in the ran ...
s along the impact structure
An impact structure is a generally circular or craterlike geologic structure of deformed bedrock or sediment produced by impact on a planetary surface, whatever the stage of erosion of the structure. In contrast, an impact crater is the surface ...
's perimeter provide some of the structure's only remaining visible evidence.
It is named for the Beaverhead
Beaverhead County is the largest county by area in the U.S. state of Montana. As of the 2020 census, the population was 9,371. Its county seat is Dillon. The county was founded in 1865.
Much of the perimeter of the county is the Continental Di ...
region of southwestern Montana in which it was first discovered.
See also
*Chesapeake Bay impact crater
The Chesapeake Bay impact crater is a buried impact crater, located beneath the mouth of Chesapeake Bay, United States. It was formed by a bolide that struck the eastern shore of North America about 35.5 ± 0.3 million years ago, in the late Eoce ...
*List of impact craters in North America
This list includes all 60 confirmed impact craters in North America in the Earth Impact Database (EID). These features were caused by the collision of large meteorites or comets with the Earth. For eroded or buried craters, the stated diameter ...
References
Further reading
* Carr, J and Link, PK, 1999, Neoproterozoicconglomerate
Conglomerate or conglomeration may refer to:
* Conglomerate (company)
* Conglomerate (geology)
* Conglomerate (mathematics)
In popular culture:
* The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes
** C ...
and breccia
Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix.
The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of d ...
in the formation of Leaton Gulch, Grouse Peak, northern Lost River Range
The Lost River Range is a high mountain range of the Rocky Mountains, located in Central Idaho, in the Northwestern United States.
It runs southeast for approximately from the Salmon River near the community of Challis to the Snake River Vall ...
, Idaho: Relation to Beaverhead Impact Structure, in Hughes, S.S., and Thackray, G.D., eds., ''Guidebook to the Geology of Eastern Idaho'': Pocatello, Idaho Museum of natural History, p. 21-29.
Aerial Exploration of the Beaverhead crater
Proterozoic impact craters Impact craters of the United States Landforms of Idaho Landforms of Beaverhead County, Montana {{US-geology-stub