Beaverhead
United States·Neoproterozoic
The Beaverhead impact structure is the second-largest impact structure in the United States, spanning across Idaho and Montana. Estimated to be 60 kilometers in diameter and approximately 600 million years old, its original form is now largely obscured, with shatter cones along its perimeter being among the few remaining visible indicators of the ancient impact.
Key Facts
- ›Diameter: Approximately 60 kilometers (37 miles).
- ›Age: Estimated at 600 million years (Neoproterozoic Era).
- ›Location: Lies within the states of Idaho and Montana, USA.
- ›Size Rank: Second-largest impact structure within the U.S.
- ›Visible Evidence: Original shatter cones along the perimeter are the primary remaining visible evidence.
- ›Discovery Context: named for the Beaverhead region of southwestern Montana where it was first discovered.
Shatter Cones
About Beaverhead
Beaverhead Impact Structure
The Beaverhead impact structure is a significant geological feature located in the United States, specifically spanning parts of Idaho and Montana. It is recognized as the second-largest impact structure within the U.S. and ranks among the largest on Earth, with an estimated diameter of 60 kilometers (37 miles).
Age and Formation
The impact event that created the Beaverhead structure is estimated to have occurred approximately 600 million years ago, during the Neoproterozoic Era. Over vast stretches of time, erosion has significantly altered the landscape, obscuring much of the original crater's form.
Visible Evidence
Despite the extensive erosion, some key evidence of the impact event remains. Original shatter cones, which are distinctive conical fracture patterns formed by the shock wave of an impact, are found along the perimeter of the structure. These shatter cones represent some of the only remaining visible indicators of the ancient impact event.
Source: Wikipedia ↗
Frequently Asked Questions
Where is the Beaverhead impact structure located?
The Beaverhead impact structure is situated within the U.S., spanning across the states of Idaho and Montana. It is named for the Beaverhead region in southwestern Montana, where it was first discovered.
How large is the Beaverhead impact structure?
The Beaverhead impact structure is estimated to be about 60 kilometers (37 miles) in diameter. This size ranks it among the largest impact structures found on Earth and makes it the second-largest within the United States.
How old is the Beaverhead impact structure?
The impact event that formed the Beaverhead structure is estimated to have occurred approximately 600 million years ago. This places its age within the Neoproterozoic Era.
What evidence remains of the Beaverhead impact structure?
Much of the original structure has been eroded or obscured over time. The most significant remaining visible evidence consists of original shatter cones found along the perimeter of the impact structure.
Related Impact Craters
Chesapeake Bay
The Chesapeake Bay impact crater is a large, deeply buried structure located beneath the mouth of the Chesapeake Bay in the United States. Formed by a high-speed bolide impact approximately 35.5 million years ago, it is one of the best-preserved "wet-target" impact craters globally and has significantly influenced the region's geology, including the formation of the Chesapeake Bay itself.
Glover Bluff
Glover Bluff is a partially exposed impact crater located in Wisconsin, United States, with an estimated diameter of 8 kilometers. Despite significant erosion, shatter cones are associated with the structure, indicating its impact origin. It remains an understudied impact site, with its exact age unconstrained beyond being at least as young as the Ordovician period.
Flynn Creek
The Flynn Creek crater, located in Jackson County, Tennessee, is a well-preserved impact structure formed approximately 360 million years ago. It is notable for its complex morphology, including a significant central uplift and folded rim strata, and its importance in understanding ancient impact events.