Fault Mapping At Raft River Geothermal Area (1993)

Jump to: navigation, search
GEOTHERMAL ENERGYGeothermal Home

Exploration Activity: Fault Mapping At Raft River Geothermal Area (1993)

Exploration Activity Details
Location Raft River Geothermal Area
Exploration Technique Fault Mapping
Activity Date 1993

Usefulness useful
DOE-funding Unknown

 
Exploration Basis
Geologic mapping, strain and kinematic analysis
 
Notes
The mountains expose a detachment fault that separates a hanging wall of Paleozoic rocks from Proterozoic and Archean rocks of the footwall. Beneath the detachment lies a 100 to 300m-thick top-to-the-east extensional shear zone. Geologic mapping, strain and kinematic analysis, and 40Ar/39Ar thermochronology suggest that the shear zone and detachment fault had an initial low-angle regional dip(<200). Along a 27 km, E-W transect across the south flank of the range, the base of the shear zone everywhere lies 20 to 60 m beneath the Archean/Proterozoic unconformity, despite an eastward-increasing lateral strain gradient. Strain analyses of mylonite coupled with the regional relationship between the unconformity and the shear zone boundary indicates that the unconformity and overlying Proterozoic metasediments were not rotated into parallelism with the shear zone boundary, but were initially subparallel (0--20).


Additional References