THE BEARTOOTH HIGHWAY MONTANA AND WYOMING: A WINDOW INTO EARTH HISTORY AND PROCESSES TO BE SHARED WITH ALL STUDENTS

The Beartooth Highway (U.S. 289) has been called the most beautiful highway in America (Charles Kuralt, On the Road), but it also traverses terrain that reveals some of the most important concepts in geology over a vertical relief of >5000 feet. The bulk of the Beartooth Mountains are underlain by a complex of Paleoarchean and Mesoarchean continental crust, including detrital zircons as old as 4.0 Ga, quartzofeldspathic gneisses dating back to 3.5 Ga, and the infrastructure of a magmatic Mesoarchean magmatic arc developed at 2.8 Ga. The mafic-ultramafic Stillwater Complex is located along the northern margin of the uplift and holds the majority of the U.S.’s Pt and Pd reserves (and once all of the Cr reserves); numerous Archean and Proterozoic mafic dikes also intrude the Beartooth massif. A major unconformity is exposed between the Archean basement and the Cambrian Flathead sandstone at Beartooth Butte. The Beartooth Range was uplifted in the Laramide Orogeny along high-angle reverse faults and is ringed by flatirons of Mississippian Madison Limestone. The Eocene Absaroka Volcanics, and related gold mining districts at Crown Butte are exposed on the southern and western parts of the range in metasedimentary rocks containing banded iron formation. The modern topography is the result of extensive glaciation, and periglacial features have developed on the high Beartooth Plateau, including striking examples of hanging valleys. The distribution of alpine and sub-alpine vegetation is largely controlled by Earth materials and processes. All of these geologic features can be readily observed using Google Earth, and can be further enhanced with allied features. Geologic maps can be overlain on the terrain to examine fundamental geological relations related to geologic time, structure, and active processes. Images, data sets, or photomicrographs can be embedded to allow students to investigate research questions in depth (e.g., orientation of fracture patterns, petrologic or geochemical relations, documentation of active surficial processes). A virtual trip through the Beartooth Mountains is one that can be personalized and distributed to students everywhere, and will hopefully inspire a boots on the ground trip to see this special area in person.