Date of Award

12-1984

Degree Name

Master of Science

Department

Geosciences

First Advisor

Dr. Christopher Schmidt

Second Advisor

Dr. Thomas Straw

Third Advisor

Dr. Ronald Chase

Access Setting

Masters Thesis-Open Access

Abstract

The northwest Tobacco Root Mountains are located on the boundary between two major tectonic provinces: the fold and thrust belt and the Rocky Mountain foreland. Deformation typical of the Rocky Mountain foreland is present in the form of two major northwest trending faults with associated folds. Paleozoic rocks were passively draped over at least one of the elevated Precambrian blocks. Foliation of the Precambrian rocks also appears to have been gently folded in the process.

Folds and thrusts occur within the Precambrian and Paleozoic rocks, on the westernmost flank of the range, appearing to follow the general trend of the fold and thrust belt. The two major thrusts dip gently northwest and show dip-slip movement. The Paleozoic thrust block is developed in thick carbonate units along the attenuated limb of an eastwardly verging anticline; and the Precambrian thrust block consists of schists, amphibolites, and quartzites with foliation trends cut by the thrust plane.

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Geology Commons

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