Graduate students

Samuel R. Neumann, PhD student; radiogenic heat production & metamorphism of continental crust: Sam started his PhD in 2026. 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. He completed an MS at UM studying high-pressure metamorphic rocks in tectonic mélanges from central Baja California, Mexico. For his PhD, Sam is researching the magmatic and metamorphic controls on the distribution of radioactive elements in Earth’s continental crust and their impact on geothermal gradients.

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.

.

Undergraduate Students

Benjamin Woodmansee, undergraduate Honors Thesis; Age of the Jurassic Sundance interior seaway, Wyoming: Ben started his involvement in the group in 2024, picking zircon and garnet grains for high-precision geochronology. In 2025, Ben conducted fieldwork with colleague L. Weaver in the Bighorn Basin of Wyoming, collecting stratigraphically controlled samples of sandstone and limestone for U–Pb dating to improve age constraints on the Middle Jurassic Sundance interior seaway.

Tess Gillum, undergraduate research; geothermal gradients of subduction zones: Tess began her research experience in 2026, calculating the expected geothermal gradient and metamorphic reactions in subducting oceanic crust as functions of subduction angle, convergence rate, friction along the plate interface, surface heat-flow of the incoming oceanic crust, thermal conductivity, and radiogenic heat production.

Kendal Boyce, undergraduate research; granulite metamorphism, crustal melting: Kendal began her research experience in 2026, conducting petrographic analysis and phase-equilibrium calculations of granulite-facies metapelites to consider the geodynamic and geothermal environments responsible for their metamorphism.

.

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.

.

Undergraduates

Astrid Olsson, undergraduate researcher; zircon mineral selection: Astrid worked with the research group in 2024–2025 to assist with hand selection of zircon grains from Archean gneisses for U–Pb dating.

Hannah Bartlett, undergraduate researcher; garnet mineral selection, tectonic block diagrams: Hannah worked with the research group in 2023–2024 to assist with hand selection of garnet grains for high-precision Lu–Hf and Sm–Nd dating of Archean gneisses as well as blocks in mélange in a Mesozoic subduction complex. Hannah also drafted 3D block diagrams to illustrate hypothesized tectonic settings for Archean magmatism and metamorphism.

Tyler Bush, undergraduate researcher; garnet mineral selection: Tyler worked with the research group in 2023–2024 to assist with hand selection of garnet grains for high-precision Lu–Hf and Sm–Nd dating of Archean gneisses.

Anna Scheck, undergraduate researcher; zircon mineral selection: Anna worked with the research group in 2024 to assist with hand selection of zircon grains from Archean gneisses for U–Pb dating.

Benjamin Bos, undergraduate researcher; garnet mineral selection: Benjamin worked with the research group in 2024 to assist with hand selection of garnet grains for high-precision Lu–Hf and Sm–Nd dating of Archean gneisses as well as blocks in mélange in a Mesozoic subduction complex.

.

Graduate students

Samuel R. Neumann, MS 2026; subduction metamorphism, tectonic mélanges: Sam 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.

Yiruo Xu, PhD 2026; Archean metamorphism, subduction 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 as well as the rates of high-pressure rock exhumation from subduction zones (Baja California, Mexico).

Julisan D. Street, MS 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. 

.

Postdocs

Charlotte H. Connop (Assistant Professor, Bates College), postdoc 2025; subduction metamorphism, tectonic mélanges, tectonic history of the North American Cordillera: Charlotte started her postdoc in 2024. She returned 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 researched the pressure-temperature-time evolution of Mesozoic ophiolite-subduction complexes in central Baja California, Mexico, as they relate to the tectonic evolution of the North American Cordillera.

David Hernández-Uribe (Assistant Professor, University of Illinois, Chicago), postdoc 2022; subduction metamorphism, intermediate-depth seismicity, slab melting: 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.