Comparison of east and west plunge areas of Casper Mountain, Wyoming
Casper Mountain extends east-west for approximately 18 mi through southeast Natrona County, Wyoming. The mountain is anticlinal, asymmetric toward the north. Its north flank is cut by the east-west-trending Casper Mountain fault, which in places juxtaposes Precambrian granite against Mesozoic strata. The mountain was thrust northward an indeterminate distance by a maximum principal south-to-north compressive stress as an integral structural unit. The west and east ends or plunge areas of the mountain are, however, markedly different. In the west, the Casper Mountain thrust fault splays or bifurcates. In the east, it is essentially a single main trace. In the west, as indicated by a trend change in fold axis and by joint analysis, the principal maximum compressive stress is vectored to north-northwest. In the east, the stress appears to have been toward the north as in the rest of the mountain. Also, the eastern end is marked by a major north-northwest-striking, high-angle, west-dipping reverse fault, a feature lacking in the west. Northward displacement of the west part of the mountain appears to have been impeded, probably by encountering and overriding the southern extension of Emigrant Gap anticline. The east end of the mountain does not appear to have been impeded, resulting in the lesser structural complications. The east-northeast grain of the Precambrian core of the mountain has only superficially influenced the structure of either end of the mountain, which is dominated by Laramide structural deformation.
- Research Organization:
- Univ. of Akron, OH
- OSTI ID:
- 7230226
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 70:8
- Country of Publication:
- United States
- Language:
- English
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Deformational stress fields of Casper Mountain, Wyoming
Oblique convergence during northeast-southwest Laramide compression along the east-west Owl Creek and Casper Mountain arches, central Wyoming