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Mark E. Stelten, PhD

Research geologist with expertise in 40Ar/39Ar and 238U-230Th geochronology. Research focuses on reconstructing the eruptive history of volcanic systems and understanding the magma plumbing systems that feed volcanic eruptions.

I have been conducting research on magmatic systems since 2008 with an emphasis on geochronology and geochemistry. The primary tool of my research is geochronology, particularly 40Ar/39Ar geochronology to determine the eruption age of volcanic rocks and 238U-230Th-226Ra geochronology to determine when the minerals hosted within volcanic rocks crystallized. By integrating geochronology with the chemical and isotopic composition of volcanic rocks and their minerals, I seek to understand (1) the eruptive history of volcanic systems, (2) how magma is generated and stored prior to volcanic eruptions, and (3) the rates and durations of volcanic eruptions.

I have worked on a variety of volcanic and plutonic systems over the course of my career. Prior to working with the U.S. Geological Survey, I conducted research on the Tuolumne Intrusive Suite in Yosemite National Park, California, South Sister volcano in Oregon, and the Yellowstone Plateau Volcanic Field in Wyoming. I began working at the U.S. Geological Survey in 2015 as a postdoc. My postdoctoral work focused on using 40Ar/39Ar geochronology to reconstruct the eruptive history of the Harrat Rahat volcanic field, Kingdom of Saudi Arabia, for the purposes of volcanic hazard assessment. Currently, I am using 40Ar/39Ar geochronology in combination with a variety of other geochemical data sets to understand the recent eruptive history at Yellowstone caldera in Wyoming, Newberry volcano in Oregon, Moffett and Adagdak volcanoes in Alaska, and the San Francisco Volcanic Field in Arizona.

In addition to studying volcanic systems, I also collaborate with researchers in the Geology, Minerals, Energy, and Geophysics Science Center to study the tectonic and geomorphic evolution of the western U.S.