Division Management Board

Chair

Brad Rosenheim is an Associate Professor at the College of Marine Science at the University of South Florida. He specializes in 14C geochronology, with experience in U-series dating as well. His research focus is global change during the late Pleistocene and through the Holocene, driven by society’s need for a natural climate change baseline for comparison to human-driven climate change. Dr. Rosenheim developed the Ramped PyrOx (pyrolysis and oxidation) technique for 14C analysis and has applied it to provide insight to a wide range of sub-disciplines of the geoscience – geochronology, pollution mapping, and biogeochemistry of rivers and the coastal zone.
Contact: brosenheim@usf.edu

First Vice Chair

Mark Schmitz is Distinguished Professor of Geochemistry at Boise State University, Idaho, USA, and has extensive research interests in the development and application of radiogenic isotope geochemistry and high-precision U-Pb geochronology to problems of Earth systems evolution. He has been an active member of the EARTHTIME community and co-editor and author for the Geologic Time Scale 2012 and 2020. He is the founder and director of the Isotope Geology Laboratory.
Contact: markschmitz@boisestate.edu

Second Vice Chair

Noah McLean is an Associate Professor of Geology at the University of Kansas. He is a statistically inclined geochronologist who specializes in U-Pb geochronology, often integrating other U decay products. His research interests include magmatic processes in large igneous systems and telling time in the sedimentary record, as well as developing cyberinsfrastructure for the geochronology and isotope geochemistry community. He has also been a part of the EARTHTIME community that contributed method development and mentorship efforts.
Contact: noahmc@ku.edu

Secretary

Courtney Sprain is an Assistant Professor in the Department of Geological Sciences at the University of Florida. At UF, she is building a state-of-the-art ⁴⁰Ar/³⁹Ar geochronology laboratory and additionally serves as co-PI of the UF Paleomagnetism laboratory. Her research focuses on the integration and development of geochemical and geophysical techniques involving ⁴⁰Ar/³⁹Ar geochronology and paleomagnetism for the comprehensive exploration of Earth’s evolution, ranging from Earth’s surface to the core, and through all of geologic time.
Contact: csprain@ufl.edu

Treasurer

Elizabeth Niespolo is an Assistant Professor in the Department of Geosciences at Princeton University. She uses geochronology, stable isotopes, and field observations to address questions regarding past climate, terrestrial paleoenvironmental reconstruction, and human evolution. She is setting up a U-series geochronology lab at Princeton, including in situ multi-element and isotopic characterization of samples using laser ablation. Her research focuses on developing and refining chronometers (40Ar/39Ar, U-series, 14C) to more meaningfully date records of Earth history, paleoclimate, evolution, and the prehistoric archaeological record.
Contact: niespolo@princeton.edu

Student Representative

Valeria Jaramillo is a third-year doctorate student at the University of California, Los Angeles. Her current projects combine structural geology, geochronology, and metamorphic petrology. She is passionate about mentoring students. During lockdown, she co-founded the EPSS Family Mentorship Program (EFMP, https://sites.epss.ucla.edu/efmp/) for the department to connect graduate and undergraduate students that would encourage a sense of community and inclusivity across the department. Valeria was also part of the On to the Future program in 2019.
Contact: jaramillov29@g.ucla.edu

Student Representative

Karissa Vermillion is a 2nd year PhD student at the University of Houston (UH) who works at the UH Helium Laboratory. As a geochronologist, Karissa seeks to better understand tectonic processes and landscape evolution utilizing thermochronology and geochemistry of common minerals (e.g., zircon and apatite) from not just basement exposures, but also detrital sands and clasts. This novel technique allows Karissa to better reconstruct the tectonic history of a region, even when the source basement is partially to completely eroded.
Contact: kvermill@cougarnet.uh.edu

Diversity Coordinator

Robin Trayler is an early career researcher and the Director of the Stable Isotope Ecosystem Laboratory at the University of California, Merced. Broadly, his research focuses on the interplay between climate and ecology over geologic timescales. He uses a variety of tools including U-Pb and radiocarbon geochronology, astrochronology, and stable isotope geochemistry. He integrates these disparate data using Bayesian timescale modeling to elucidate the rate and tempo of climatic and ecological change. Currently, Robin is working on developing joint inversions of astrochronology and radioisotope geochronology in deep time, and also untangling the chronology of tar seep fossils sites in California.
Contact: rtrayler@ucmerced.edu

Past Chair (2022-2023)

Andrea Dutton is a Professor of Geoscience at the University of Wisconsin-Madison. She is a U-series geochronologist who combines a range of disciplines such as carbonate sedimentology, geophysics, and coral reef ecology to study past changes in sea level and climate through time. Her recent research has focused on understanding the rates, magnitudes, sources, and drivers of past sea-level change to facilitate a better understanding of future sea-level rise and ice sheet retreat.
Contact: dutton3@wisc.edu

Outgoing Past Chair (2021–2022)

Rebecca Flowers is an Associate Professor in the Department of Geological Sciences at the University of Colorado – Boulder, where she directs the CU Thermochronology Research and Instrumentation Lab (CU TRaIL). Becky has used thermochronology, geochronology, and geologic observations to address a variety of problems that include deciphering the missing sedimentary record of continental interiors, the erosion history of the Great Unconformity, the topographic evolution of the southern African Plateau and western U.S., and the impact history of the moon. Her group’s research also focuses on developing and refining (U-Th)/He thermochronometers.
Contact: rebecca.flowers@colorado.edu

Historian/Founding Chair (2018-2019)

Leah Morgan is a geochronologist in the ⁴⁰Ar/³⁹Ar geochronology lab at the USGS in Denver, Colorado, working on a range of applications and method development issues in ⁴⁰Ar/³⁹Ar geochronology. Applications have largely focused on questions in paleoanthropology, geologic mapping, and ore deposits. Method development projects include developing metrologically traceable systems for measuring absolute quantities of ⁴⁰Ar and ⁴⁰K, and the design of a mobile neutron source for the future in situ deployment of ⁴⁰Ar/³⁹Ar capabilities on planetary surfaces.
Contact: leahetgmorgan@gmail.com

Past Student Representative

Emily Mixon is a third year PhD student at the University of Wisconsin-Madison where she initially worked on the application of ⁴⁰Ar/³⁹Ar geochronology to Quaternary arc volcanism in the Southern Volcanic Zone of Chile, and is now utilizing U-Pb, Lu-Hf and Sm-Nd isotopic systems in tandem with field mapping and petrographic observations to answer questions about early crustal growth. She holds a BSc in Geology from the University of Texas at Austin, where she first began to foster her interests in subduction zone fluids, climate-deep earth feedbacks, and mass spectrometry methods. She is passionate about mentorship and equity in the Geosciences and is excited to serve as a voice for student participation within the Geochronology Division Board.
Contact: eemixon@wisc.edu

Outgoing Past Chair (2020–2021)

Alan Rooney is an Assistant Professor at Yale University and co-director of the Yale Metal Geochemistry and Geochronology Center. His research focuses on the application of radiogenic isotopes, in particular the Re-Os and Sm-Nd systems in conjunction with field mapping, sedimentology and stratigraphy to investigate interactions between tectonics, climate change and the evolution of complex life across a range of timescales.
Contact: alan.rooney@yale.edu

Outgoing Secretary/Treasurer

Julie Fosdick is an Assistant Professor at the University of Connecticut and director of the Basin Analysis and Thermochronology Laboratory. Her research focuses on tectonics and sedimentation during mountain-building, with expertise in (U-Th)/He thermochronology, detrital U-Pb geochronology, and sedimentary basin analysis. Recent projects center on better understanding timing and rates of tectonic deformation and exhumation, landscape evolution, and magmatic processes.
Contact: julie.fosdick@uconn.edu

Outgoing Past Chair (2019–2020)

George Gehrels is a Professor of Geosciences at the University of Arizona. Dr Gehrels conducts research in tectonics and geochronology, and serves as the director of the Arizona LaserChron Center. The ALC is an NSF-supported multi-user facility that provides U-Th-Pb geochronology and complementary Lu-Hf and T/REE geochemistry by LA-ICPMS.
Contact: ggehrels@gmail.com

Past Student Representative

Elizabeth Bollen is a fourth year PhD candidate at the University of Alabama where she studies the co-use of high-temperature metamorphic chronometers. She serves as a voice for student involvement, participation, and communication with the Geochronology Division board.
Contact: embollengeo@gmail.com