Date of Award:
Master of Science (MS)
Clyde T. Hardy
The mapped area represents the eastern three-fourths of the Malad Summit Quadrangle, Idaho. It lies mainly in the Bannock Range of southeastern Idaho. The northern and southern margins of the area are 25.5 miles and 17.0 miles, respectively, north of the Idaho-Utah State Line.
The Caddy Canyon Formation of Late Precambrian age is the oldest exposed stratigraphic unit. The youngest unit, exclusively of Precambrian age, is the Mutual Formation. The Brigham Formation is considered to be of Late Precambrian to Early Cambrian(?) age. Younger formations of Cambrian to Silurian age are present. The Precambrian units, as well as the Brigham, consist chiefly of quartzite. Younger Paleozoic units are primarily limestone and dolomite. The Precambrian and Paleozoic units are unconformably overlapped by the Wasatch and Salt Lake Formations of Tertiary age.
A major thrust fault is widely exposed in the mapped area. It places various formations of early Paleozoic age in thrust contact with the Brigham Formation. Several minor thrust faults are also present. The thrust faulting is related to the Laramide orogeny which was active in western United States from late Jurassic into Eocene.
Normal faults, in the mapped area, trend generally north-south x and east-west. The north-south faults, characteristic of the Basin and Range province, are responsible f or most of the relief in the area. The normal faulting began as early as Oligocene and has continued intermittently to the present.
Shearer, Jay Nevin, "Structural Geology of Eastern Part of the Malad Summit Quadrangle, Idaho" (1975). All Graduate Theses and Dissertations. 6657.