UW and USGS Discover Relationship Between Basaltic and Rhyolitic Eruptions
Published April 25, 2025
Kenneth Sims and other research scientists recently discovered that mafic volcanism of Henrys Fork Caldera, which is located in eastern Idaho and west of Yellowstone National Park, occurred concurrently with second- and third-cycle rhyolite volcanism in and around the Yellowstone caldera.
The revelation, detailed in a recently published paper, helps provide a new and younger timeline of volcanic activity in the Henrys Fork Caldera region and adds knowledge to the chronology of mafic eruptions and their temporal relation to rhyolitic volcanism in the Yellowstone Plateau volcanic field, of which little was previously known. “Essentially, it changes our understanding of the Yellowstone magmatic system by showing how basaltic eruptions have ‘thermally primed’ Yellowstone's big caldera-forming eruptions and shows that there are some very young eruptions in the Henrys Fork Caldera,” says Sims, a University of Wyoming professor of geology and geophysics and a member of the United States Geological Survey (USGS) Yellowstone Volcano Observatory.
