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GEOREF RECORD

Intertongued Upper Cretaceous volcanic and nonvolcanic rocks, central-western Montana

V. E. Gwinn and T. A. Mutch
Intertongued Upper Cretaceous volcanic and nonvolcanic rocks, central-western Montana
Geological Society of America Bulletin (1965) 76 (10): 1125-1144

Abstract

Upper Cretaceous intertonguing volcanic and nonvolcanic rocks, 4,000 to 8,000 feet thick, a western facies of the Elkhorn Mountains Volcanics, exposed in a 9-mile-long belt west of Garrison, Mont., are named the Golden Spike Formation. A thin sequence of fluviatile nonvolcanic clastics, derived from Laramide orogenic uplifts to the west and northwest, dominates the northwestern part of the belt, and intertongues southeastward with a thick sequence of lavas and of volcaniclastic rocks probably deposited by mud flows, landslides, and running water from the Elkhorn Mountains volcanic field. Pyroclastics did not reach the area of fluviatile nonvolcanic deposition either because explosive activity was minimal or because prevailing winds were westerly then as now.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 76
Serial Issue: 10
Title: Intertongued Upper Cretaceous volcanic and nonvolcanic rocks, central-western Montana
Pages: 1125-1144
Published: 1965
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
Accession Number: 1965-018584
Categories: Sedimentary petrologyStratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus., tables, geol. map
N44°30'00" - N49°00'00", W116°01'60" - W104°01'60"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
Update Code: 1965
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