Date of Award
Master of Science
Dr. Christopher Schmidt
Dr. Thomas Straw
Dr. Ronald Chase
Masters Thesis-Open Access
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.
Samuelson, Kiff James, "Geology of a Section of the Northwest Tobacco Root Mountains, Madison County, Southwest Montana" (1984). Master's Theses. 1550.