Document Type
Article
Journal/Book Title/Conference
Guidebook to the Geology of eastern Idaho
Publication Date
1999
First Page
71
Last Page
96
Abstract
Previous studies identified a major detachment terrane in southeast Idaho in the Oxford Ridge area of the Bannock Range. This study shows that these top-to-the-WSW detachment faults are late Cenozoic in age, not Mesozoic to early Tertiary as previously inferred. Provenance and facies patterns in the Miocene-Pliocene Salt Lake Formation in the Deep Creek supradetachment basin show that deposition was syntectonic to slip on the detachment faults. The highly extended Bannock detachment terrane likely persists north to the Snake River Plain and south into Utah. The breakaway for this system lies in the Portneuf Range to the east. At least one and possibly three generations of normal faults postdate the large-magnitude extension along the Bannock detachment system. Extensional folds, including folds with vertical limbs, are plentiful within the hanging wall of the detachments and formed in association with each generation of normal faults. The modern Basin-and-Range extension in this area initiated in latest Cenozoic time.
Recommended Citation
Janecke, S. U., and Evans, J. C., 1999, Folded and faulted Salt Lake Formation above the Miocene to Pliocene New Canyon and Clifton detachment faults, Malad and Bannock Ranges, Idaho: Field trip guide to the Deep Creek half graben and environs: Guidebook to the Geology of eastern Idaho, Hughes, S. and Thackray, G, eds. , Idaho Museum of Natural History, p. 71-96. http://imnh.isu.edu/digitalatlas/geo/snkrvpln/snkrvpln.htm
Comments
the rest of the volume is at this link: https://digitalatlas.cose.isu.edu/geo/snkrvpln/snkrvpln.htm Select chapter 5. or download the attached file.