WSU Researchers Compare Rocky Mountains to Andes

OGDEN, Utah – A $325,000 National Science Foundation (NSF) grant will allow WSU geosciences faculty and students to compare actively forming mountain ranges in Argentina to the Rocky Mountains in Colorado and Wyoming.
WSU geosciences professor Adolph Yonkee and his long-time research collaborator Arlo Weil, chair of the geology department at Bryn Mawr College in Pennsylvania, have been awarded NSF funding to begin a three-year study of the Andes Mountains. They and undergraduate research assistants will travel to the Mendoza region of Argentina to collect rock samples and take measurements. The samples and data will be analyzed in depth at the two universities in coordination with geodynamic studies at the Center for Scientific and Technical Research in Mendoza and the University of Arizona.
As part of previous research grants, Yonkee, Weil and their students have studied faults and fractures related to ancient stress fields that produced the Sevier and Laramide mountain belts in western North America.
Students from the University of Arizona and the Center for Scientific and Technical Research in Mendoza, consider locations for the upcoming geosciences research with Weber State University.
“Now what we want to do is apply that same methodology to mountains that are forming today, such as those in Argentina,” Yonkee said. “We can actually see the process happening in real time.”
The mountain-building process they are studying is known as flat-slab subduction, where an oceanic plate bends and plunges beneath a continental plate. Although geoscientists understand the general concept, the process of the stress transfer between plates to form mountains remains debated.

“Our previous work has provided clear evidence that flat-slab subduction directly contributed to forming the Laramide mountain belt,” Yonkee said. “The next test is to compare patterns of active mountain building in Argentina where a modern flat-slab can be seen seismically beneath part of the Andes, including Mount Aconcagua, the highest point in the western hemisphere.”

The research offers a chance to improve understanding and public awareness of seismic risks in the Mendoza region, which has experienced multiple devastating historic earthquakes. For example, a magnitude 7.0 earthquake occurred in 1861 on the La Cal fault and destroyed the old city of Mendoza, Argentina, killing 6,000 people, half the city’s population. Today, more than 1 million people inhabit Mendoza, which was rebuilt over the still-active fault.
Yonkee and WSU student researchers will join their Bryn Mawr colleagues and travel to Argentina a total of five times in three years. The goal is to understand mountain building while building collaborative ties with Argentinian researchers — two of whom visited Weber State and toured the Rocky Mountains in fall 2013. In the spirit of collaboration and learning, Yonkee has enrolled in an upcoming Spanish class.

He received word of the NSF funding while participating in WSU’s annual four-week field camp for geology majors. While exploring geology closer to home at Little Mountain with his group of field-camp students, Yonkee expressed his enthusiasm for the upcoming research opportunity. “Estoy muy mocionado — I am very excited,” he said.

Yonkee and WSU geology student Chase Dickinson will leave for their first three-week exploration of the Andes in August.
“This type of collaborative, international field experience will enhance the skills and training of our students,” Yonkee said. "It will also expose them to diverse cultural backgrounds.”

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Adolph Yonkee, geosciences professor
Allison Barlow Hess, Director of Public Relations
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