Isotopic composition of units within the Absaroka volcanic province

Isotopic composition of the primary volcanic groups of the Absaroka volcanic province (the Washburn, Sunlight, and Thorofare groups) and two volcaniclastic units, the Sepulcher formation and the Daly formation. Based on their location (seen on the map), the two volcaniclastic units were expected to correlate with the Washburn group data (all other data were collected from samples off the map). Both volcaniclastic rocks isotopically match up with the Washburn group data, indicating we can better understand the origin of volcaniclastic units in Yellowstone National Park using isotopes. Figure by Natali Kraugh, Montana State University.