The Middle Yellowstone Valley from Livingston to Gardiner, Montana: A Microcosm of Northern Rocky Mountain Geology

Route

Start point

Bozeman, MT

End point

Gardiner, MT (roadlog returns to Bozeman)

Roads

I-90, U.S. 89, Montana 540, Pine Creek Road, and other minor roads

Total distance

178.7 miles

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Geology

Summary

The middle Yellowstone (Paradise) valley, between the Great Plains at Livingston and the edge of the Yellowstone volcanic plateau near Gardiner, is a complex palimpsest of lithology, structure, and surficial processes. It shares basement rocks with the continental interior, largely to the north and east; Paleozoic lithologies with the western interior, compressive tectonics with the Fold and Thrust Belt to the west; extension with the Basin and Range to the west and south; and Cenozoic volcanism and elements of its geomorphic evolution with much of the surrounding region. The geological exploration of this region serves as a microcosm of the evolution of the geological understanding of the American West.

Key Lithologic Features

• Paleozoic, Mesozoic, and Cenozoic sedimentary rocks
• Various glacial deposits (Wisconsinan/Pinedale age)
• landslide deposits in the Yellowstone (Paradise) valley
• Nelson and Armstrong Springs, northern Paradise Valley
• several rangefront alluvial fans
• Metamorphic basement rocks of the North Snowy Block, viewed from near Pine Creek
• Hydrothermal features at Chico Hot Springs
• Fossiliferous Miocene lacustrine rocks of the Hepburns Mesa Formation
• Point of Rocks volcanic/intrusive center (Absaroka Volcanic Field)
• Glacial deposits in Tom Miner Basin
• Landslide deposits and lacustrine siltstones related to the Yankee Jim Landslide
• Hydrothermal features at La Duke Hot Spring
• Travertine deposits at Gardiner
• Megaripples in flood bars near Gardiner
• Devils Slide (steeply-dipping Cambrian through Cretaceous formations)

Structures

• Various folds, faults, and range-front fault scarps
• Cenozoic extensional faults on the east side of the Yellowstone Valley

Landforms

• Yellowstone (Paradise) Valley
• Gallatin Range
• Beartooth Range
• Hepburn Mesa
• Tom Miner Basin
• Yankee Jim Canyon

Other Features

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Reference

Locke, W.W., Clarke, W.D., Custer, S.G., Elliott, J.E., Lageson, D.R., Mogk, D.W., Montagne, J., Schmitt, J.G., and Smith, M., 1995, The middle Yellowstone Valley from Livingston to Gardiner, Montana: A microcosm of northern Rocky Mountain geology: Field guide to geologic excursions in Southwest Montana , Northwest Geology, v. 24, p. 1-65.

Availability

Order from the Tobacco Root Geological Society. Go to the List of available TRGS publications for ordering information.