Structural interactions between the Uinta arch and the overthrust belt, north-central Utah; Implications of strain trajectories and displacement modeling
Michael D. Bradley, Ronald L. Bruhn, 1988. "Structural interactions between the Uinta arch and the overthrust belt, north-central Utah; Implications of strain trajectories and displacement modeling", Interaction of the Rocky Mountain Foreland and the Cordilleran Thrust Belt, Christopher J. Schmidt, William J. Perry, Jr.
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Analysis of mesoscopic structures in the Jurassic Twin Creek Formation reveals two major periods of deformation in the central Wasatch and westernmost Uinta Mountains during Late Cretaceous through early Eocene time. Spaced cleavage, extension veins, and tension gash bands developed early in the evolution of the Mount Raymond thrust fault and were subsequently folded around first-phase folds as deformation progressed. First-phase folds occur as trains of northeast-plunging, asymmetric anticlines and synclines, with an overall eastward vergence.
A second spaced cleavage and associated extension veins and tension gash bands developed after the first-phase folding and prior to the development of second-phase folds. The first-phase and early second-phase structures were subsequently folded into east-northeast-trending second-phase anticlines and synclines during evolution of the Uinta arch.
The Uinta arch in the central Wasatch and westernmost Uinta Mountains formed during Late Cretaceous to early Eocene time, partly in response to movement on the Hogsback thrust. Two possible models, which are consistent with the field data for the evolution of the Uinta arch, are (1) dextral wrench strain along the southern termination of the Hogsback thrust, and (2) dextral transpression along a south-dipping ramp where the Hogsback thrust cut down along the northern boundary of the basin in which the Middle Proterozoic Uinta Mountain Group was deposited.