FROM 3.4 GA TO PRESENT: TEACHING AND RESEARCHING THE GEOLOGY OF WYOMING’S SHOSHONE NATIONAL FOREST AND MONTANA’S CUSTER AND GALLATIN NATIONAL FORESTS

Geologically speaking, the Shoshone, Custer, and Gallatin National Forests have nearly everything. Rocks range from Archean to Cenozoic, with every Phanerozoic period but the Silurian represented. There are Precambrian plutonic and metamorphic rocks, Paleozoic and Mesozoic clastics and carbonates, Tertiary volcanic and sedimentary rocks, and Quaternary sediments. The dramatic landscape is a result of faulting, folding, and mass wasting; fluvial, glacial, and periglacial activity; and minor eolian and karst processes.

Many geologists had their first exposures to western geology at field camps (e.g., the University of Pennsylvania’s Yellowstone Bighorn Research Association) based nearby or traveling through the area. Some institutes of higher education (e.g., the University of Pittsburgh and Whitman College) offer summer courses for students and/or alumni on the Greater Yellowstone Ecosystem, including the geology of these national forests. Keck Geology Consortium undergraduate research projects shed light on glaciation along Clarks Fork of the Yellowstone River, mechanics of the Heart Mountain Detachment, and other topics.

Particularly interesting geologic phenomena include 3.4-Ga metamorphic rocks at Quad Creek, the 2.7-Ga Stillwater Complex, Devonian fish fossils at Beartooth Butte, Eocene dikes and sills at White Mountain and Pilot Peak, gold mines at Crown Butte, the sackung on Dead Indian Hill, tors and patterned ground on the Beartooth Plateau, the subaqueous moraine complex in Sunlight Basin, postglacial gorges in the Pilgrim Limestone, the Galena Creek rock glacier, and landslides below Cathedral Cliffs. The national forests north and east of Yellowstone have a variety of rocks and landforms that make this area ideal for geologic education.