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GEOREF RECORD
Shatter cones and shocked rocks in southwestern Montana; the Beaverhead impact structure
R. B. Hargraves, C. E. Cullicott, K. S. Deffeyes, S. Hougen, P. P. Christiansen and P. S. Fiske
Shatter cones and shocked rocks in southwestern Montana; the Beaverhead impact structure
Geology (Boulder) (September 1990) 18 (9): 832-834
Shatter cones and shocked rocks in southwestern Montana; the Beaverhead impact structure
Geology (Boulder) (September 1990) 18 (9): 832-834
Index Terms/Descriptors
- Beaverhead County Montana
- Belt Supergroup
- clastic rocks
- cryptoexplosion features
- deformation
- field studies
- gneisses
- impact features
- impacts
- Mesoproterozoic
- metamorphic rocks
- metamorphism
- Montana
- North America
- petrology
- Precambrian
- Proterozoic
- Rocky Mountains
- sandstone
- sedimentary rocks
- shatter cones
- shock metamorphism
- United States
- upper Precambrian
- southwestern Montana
- Beaverhead impact structure
Latitude & Longitude
Abstract
Shatter cones that point steeply upward are present in abundance over an area >100 km (super 2) in Belt Supergroup sandstone outcrops in Beaverhead County, southwestern Montana. Crushed sandstone with fragments dispersed in a fluidal textured, cryptocrystalline matrix of similar chemical composition has also been found. Absence of cones in adjacent units of Mississippian and younger age suggests a late Precambrian-early Paleozoic age for the formation of this newly discovered impact structure, only a small part of which is preserved in the complexly faulted terrain.
ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 18
Serial Issue: 9
Title: Shatter cones and shocked rocks in southwestern Montana; the Beaverhead impact structure
Affiliation: Princeton Univ., Dep. Geol. and Geophys. Sci.,
Princeton, NJ,
United States
Pages: 832-834
Published: 199009
Text Language: English
Publisher: Geological Society of America (GSA),
Boulder, CO,
United States
References: 8
Accession Number: 1990-050488
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: 1 table, geol. sketch map
N44°00'00" - N44°45'00", W113°30'00" - W112°30'00"
Secondary Affiliation: Stanford Univ.,
USA,
United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1990
