Provenance, dispersal, and tectonic significance of the Evanston Formation and Sublette Range Conglomerate, Idaho-Wyoming-Utah thrust belt

Journal Article · Mon Dec 31 23:00:00 EST 1990 · Mountain Geologist; (United States)

OSTI ID:5617144

Salat, T S ^[1]; Steidtmann, J R ^[2]

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1. ARCO Alaska, Inc., Anchorage (United States)
2. Univ. of Wyoming, Laramie (United States)

Tectogenic sediments of the latest Cretaceous-Paleocene Evanston Formation were deposited in proximal braided streams in northeastern Utah, and in distal gravelly rivers in the Fossil basin of southwestern Wyoming. Paleocurrent data provide evidence for a north-to-south axial drainage system in both areas. The ubiquitous presence of Precambrian-Cambrian clast types throughout the Evanston Formation indicates a source area in the present day Bear River Range (Paris and Willard thrust plates). The Sublette Range Conglomerate is a crudely stratified, clast-supported, proximal braided stream deposit. Paleocurrent data and clast lithology also indicate a north-westerly source area on the Paris and Willard plates. It is proposed that the undated Sublette Range Conglomerate is a remnant of a proximal deposit which linked distal Evanston sediments in the Fossil basin with their source area on the Paris and Willard plates. Early Eocene reactivation of the Crawford thrust resulted in the present elevated position of the Sublette Range Conglomerate.

• OSTI ID: 5617144
• Journal Information: Mountain Geologist; (United States), Journal Name: Mountain Geologist; (United States) Vol. 28:1; ISSN MOGEA; ISSN 0027-254X
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CENOZOIC ERA
CONGLOMERATES
CRETACEOUS PERIOD
DEPOSITION
DEVELOPED COUNTRIES
DRAINAGE
ENVIRONMENTAL TRANSPORT
FEDERAL REGION VIII
FEDERAL REGION X
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGY
IDAHO
LITHOLOGY
MASS TRANSFER
MESOZOIC ERA
NORTH AMERICA
ORIGIN
ROCKS
SEDIMENTARY ROCKS
SEDIMENTS
SOURCE ROCKS
STRATIGRAPHY
TECTONICS
TERTIARY PERIOD
USA
UTAH
WESTERN US OVERTHRUST BELT
WYOMING