Structural geology of the Sawtooth Range at Sun River Canyon, Montana Disturbed Belt, Montana
Published:January 01, 1987
David R. Lageson, 1987. "Structural geology of the Sawtooth Range at Sun River Canyon, Montana Disturbed Belt, Montana", Rocky Mountain Section of the Geological Society of America, Stanley S. Beus
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The Sawtooth Range is located in northwest Montana in parts of Pondera, Teton, and Lewis and Clark counties. The range is part of the Rocky Mountain fold and thrust belt, or Disturbed Belt, and lies between Glacier National Park to the north and the Helena salient to the south. In an analogy with the Canadian Rocky Mountains, the Sawtooth Range would represent the Front Ranges of the Rocky Mountain thrust belt (Mudge, 1972; Bally and others, 1966).
The Sun River and its tributaries form the major drainage system in the southern part of the Sawtooth Range. Two dams have been constructed on the Sun River creating Gibson Reservoir and Diversion Lake (Fig. 1).
The entrance to the Sun River Canyon is approximately 20 mi (32 km) northwest of Augusta, Montana. Turn west on Montana 435 (U.S. Forest Service Road 208) at the intersection of highways U.S. 287 and Montana 434–435 in Augusta. Montana 435 is a year-round gravel road that ends at Gibson Dam (Fig. 1). Spectacular exposures of imbricate thrust faults and related structures are found in the lower part of the canyon downstream from Gibson Dam.
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Rocky Mountain Section of the Geological Society of America
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