Beaverhead crater
Encyclopedia
Beaverhead is an impact structure
in central Idaho
and western Montana
in the United States
.
Estimated at 60 kilometres (37.3 mi) in diameter, it is one of the largest impact craters on Earth. Its age is estimated to be about 600 million years (early Neoproterozoic
).
The structure is named after the area
in southwest Montana where evidence of an impact was first discovered in 1990.
Other than the original shatter cone
s found on the perimeter, there is little visible evidence of the structure.
Impact structure
The term impact structure is closely related to the terms impact crater or meteorite impact crater, and is used in cases where erosion or burial have destroyed or masked the original topographic feature with which we normally associate the term crater...
in central Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
and western Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
Estimated at 60 kilometres (37.3 mi) in diameter, it is one of the largest impact craters on Earth. Its age is estimated to be about 600 million years (early Neoproterozoic
Neoproterozoic
The Neoproterozoic Era is the unit of geologic time from 1,000 to 542.0 ± 1.0 million years ago. The terminal Era of the formal Proterozoic Eon , it is further subdivided into the Tonian, Cryogenian, and Ediacaran Periods...
).
The structure is named after the area
Beaverhead County, Montana
-National protected areas:* Beaverhead National Forest * Big Hole National Battlefield* Nez Perce National Historical Park * Red Rock Lakes National Wildlife Refuge-History:...
in southwest Montana where evidence of an impact was first discovered in 1990.
Other than the original shatter cone
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...
s found on the perimeter, there is little visible evidence of the structure.
See also
- Chesapeake Bay impact craterChesapeake Bay impact craterThe Chesapeake Bay impact crater was formed by a bolide that impacted the eastern shore of North America about 35 million years ago, in the late Eocene epoch. It is one of the best-preserved "wet-target" or marine impact craters, and the largest known impact crater in the U.S...