Displacement transfer between the Meade and Crawford thrusts, Idaho-Wyoming thrust belt

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6875841

Evans, J P; Craddock, J P

Balanced, restorable cross sections through the central part of the Idaho-Wyoming thrust belt demonstrate that it is a region of stratigraphically controlled thrust to thrust displacement transfer. Displacement on the Meade thrust is the northern part of the region is 37 km, where it places Mississippian Madison Group of Jurassic Twin Creek Limestone. The Meade thrust cuts down stratigraphically in the footwall to the south, placing the Madison Group on Permian Phosphoria Formation. Displacement on the Meade thrust in the southernmost cross section is 20 km. Displacement on the Crawford thrust to the east is 11 km, where it places the Phosphoria Formation on Cretaceous Cokeville Formation. Displacement on the Crawford thrust decreases to the north, where it terminates in an overturned anticline. Despite changes in displacement on the individual thrusts, shortening is nearly the same in all cross sections. Shortening in the northern part of the area is accommodated by translation on long hanging wall flats in the Meade thrust. These flats may occur in paleo-karst horizons in the Madison Group. Folding above and motion along the Crawford and Meade thrusts is responsible for the shortening of the southern part of the area. While the Meade and Crawford thrusts developed at nearly the same time (85-95 my) the regional cross sections show that the thrusts have separate detachment horizons. Shortening remained constant throughout the region by changes in the levels of detachment and by folding above decollement horizons.

• Research Organization: Texas A and M Univ., College Station (USA)
• OSTI ID: 6875841
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
CROSS SECTIONS
FEDERAL REGION VIII
FEDERAL REGION X
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
GROUND MOTION
IDAHO
MOTION
NORTH AMERICA
STRATIGRAPHY
TECTONICS
USA
WESTERN US OVERTHRUST BELT
WYOMING