People
Current group members
Samuel R. Neumann, MS student; subduction metamorphism, tectonic mélanges
Sam joined the group in 2024. He finished his undergraduate degree in Geology at the University of Illinois, Urbana-Champaign, where he did a senior thesis using Pb-isotopes to study magma chamber evolution and volcanic eruptions. At UM, Sam is researching the evolution of a Mesozoic subduction zone through study of high-pressure metamorphic rocks in tectonic mélanges from central Baja California, Mexico.
Hannah Y. Schroeder, PhD student; Archean metamorphism and tectonics
Hannah joined the group in 2022. She finished her undergraduate major in Geology and Environmental Sciences, where she did a senior thesis studying the organization of leucosome networks in migmatites from the Pioneer Metamorphic Core Complex of Idaho. At UM, Hannah is researching the timescales and drivers of Archean metamorphism in the English River Subprovince of the Superior Province, Northwest Ontario, Canada.
Yiruo Xu, PhD student; Archean metamorphism, diffusion chronometry
Yiruo started her PhD in Fall 2021. She completed her undergraduate degree in Geology and Economics at Vanderbilt University, where she worked on a senior thesis evaluating the source of Paleozoic volcanic ashes (K-bentonites) in the eastern USA and using Ce anomalies in zircon to estimate the oxygen fugacity of their magmas prior to eruption. At UM, Yiruo is researching the timescales and drivers of Archean metamorphism and magmatism in the Minnesota River Valley (MN, USA) and Quetico Subprovince (Northwest Ontario, Canada) of the Superior Province.
Charlotte H. Connop, postdoc; subduction metamorphism, tectonic mélanges
Charlotte started her postdoc in 2024. She returns to UM, where she got her BS, after completing her PhD at Penn State. Broadly, she is interested in the geochemical cycling processes active within the crust and at the crust-mantle interface. Her previous projects have focused on the heat sources for metamorphism and partial melting of the continental crust during mountain building as well as the dependence of S-type granite production on sedimentary rock composition. At UM, Charlotte is researching the pressure-temperature-time evolution of Mesozoic ophiolite-subduction complexes in central Baja California, Mexico.
Robert M. Holder, Assistant Professor
Robert started at the University of Michigan in July 2020 after finishing a postdoc at Johns Hopkins University with Daniel Viete, MS+PhD at UC Santa Barbara with Brad Hacker, and BA at Gustavus Adolphus College (Geology & Scandinavian Studies). He is interested in the evolution of ancient mountain belts and how Earth’s fundamental tectonic processes have changed through time. His work has primarily focused on metamorphism, but also touches on traditional igneous and sedimentary processes. He uses a variety of laboratory techniques, but is most known for his application of U–Pb petrochronology by LA-ICP-MS. He has worked in Antarctica, Austria, Canada, Czech Republic, Madagascar, Mexico, Norway, Shetland, and the USA.
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Former group members
Julisan D. Street, MS thesis 2024; granulite metamorphism, crustal melting
Julisan finished her undergraduate major in Geology and minor in Anthropology & Sociology at Lafayette College, where she worked on a senior thesis studying the origin of Jamaican adakite volcanism as a possible analog for Archean magmatic process. At UM, Julisan studied the causes of high-temperature metamorphism and crustal melting in the Paleoproterozoic Mojave Province of the southwest USA.
David Hernández-Uribe, postdoc; subduction metamorphism, intermediate-depth seismicity, slab melting
Assistant Professor at the University of Illinois, Chicago. David worked in the group as a postdoc from 2020 to 2022 and is still an active research collaborator. He completed his PhD at the Colorado School of Mines, his MS at Central Washington University, and his BS at la Universidad Nacional Autónoma de México. He is broadly interested in subduction zone processes. His previous projects have focused on the formation and exhumation of ultrahigh-pressure metamorphic rocks, flat-slab subduction in SW USA, volatile cycling between the crust and mantle, intermediate-depth seismicity, and the scenarios that lead to slab melting. He has worked with rocks from China, Mexico, USA, and Guatemala in addition to theoretical modeling of metamorphic phase equilibria in subducting slabs. As a postdoc at UM, he conducted theoretical modeling of phase changes in subducting slabs as they relate to deep seismicity, slab melting, volatile recycling, and arc magmatism.