Student Research Projects

Geologic Mapping of the Briggs Ranch Quadrangle, Beaverhead County, Montana

Student Timothy S. Turk
Mark Messina
Faculty Mentor(s)
Department Earth and Environmental Sciences
Course EES 490: Geologic Mapping in Southwest Montana


In the summer of 2005 we spent six weeks mapping the geology of the Briggs Ranch Quadrangle in the northern Rocky Mountains. Geologic mapping is the first step in studying the geologic evolution of a region. It involves documenting the rock types in an area and recording their distribution and orientation with a goal of providing base-line data for future studies. Our area is located in the deep foreland basin located just east of the southwest Montana fold and thrust belt. We mapped the coarse conglomerates that were shed into the basin off the rising and eroding mountains about 75-65 million years ago, identifying at least three genetically distinct deposits from three different uplifted regions. We also mapped newly discovered volcanic intrusions, which will require further study.

Research sponsored by U.S. Geological Survey EDMAP grant number 05HQAG0067, Virginia Wesleyan Science Undergraduate Research Fund and Virginia Wesleyan Faculty Development Grant.