Geology students and researchers from Idaho State University traveled to South America in December 2025 to investigate the origins of the Andes mountains, according to an April 9 announcement. The group included undergraduate students Tiana Hursh and Parker Hazelbush, along with National Science Foundation postdoctoral fellow Chance Ronemus.
The project seeks to answer key questions about how continents grow, how Earth’s crust is recycled, and how mineral resources are formed. Understanding the formation of the Andes could shed light on these fundamental geological processes.
Ronemus explained that traditional views hold that the Andes formed through steady subduction of oceanic plates beneath South America. However, “recent imagery of Earth’s deep interior challenges this view, suggesting instead that a chain of volcanic islands—perhaps resembling modern Japan—may have crashed into and merged with South America about 100 million years ago.” He said, “Answering this fundamental question will improve our understanding of how continents grow, how Earth’s crust is recycled back into the mantle, and how and where valuable mineral resources are formed.”
Before departing for fieldwork in Chile and Argentina, Hursh and Hazelbush prepared by reviewing research papers and studying geologic maps. In Argentina’s Neuquén Basin, Ronemus worked with Lucas Fennell from the University of Buenos Aires to examine ancient desert pavements called Rodados Lustrosos. These rocks provide clues about past arid conditions in South America.
In Chile, Hursh described camping near their study site: “We were camping right off the beach where our formation that we were studying was, so we were able to just wake up and go right to the field site.” The team collected samples of turbidites—sedimentary rocks formed by underwater avalanches—and observed rare features such as hummocky cross-strata. Hazelbush noted differences from Idaho geology: “I’ve never seen a lot of the depositional environments that we were actually looking at… We don’t have turbidites like that (in Idaho).”
After returning home, students Amarissa Cramer and William Crater took over laboratory work analyzing zircon minerals from rock samples using geochronology techniques. Cramer said: “What I find interesting about this project is the investigative aspect… as we use zircon ages to piece together history.” Crater added: “Getting to do this firsthand… is a very cool opportunity I’ve been granted… it makes me excited to continue to do more research as I keep going to school here.”
The team presented preliminary results at Idaho State University’s Research Symposium in March. They plan further presentations at national conferences later this year while continuing their analysis on whether an island arc collision or another tectonic process shaped western South America.
