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Blair Schoene - Group, recent past and present

jenn kasbohm

Jennifer Kasbohm, Ph.D. Student

As geography is vital to understand patterns of glaciation and sea level rise in our present world, it is also necessary for the study of Earth’s past. Crucial Precambrian questions, ranging from the nature of Archean tectonics to the rise of animal life, depend upon knowledge of where continents were located and how quickly they moved. My research will use paleomagnetism and geochronology to find these locations and rates, and to learn more about Earth's ancient geomagnetic field. By placing these tools in the context of stratigraphic field observations, I aim to produce novel continuous records of plate motion. My first field season tackled crucial intervals in the 2.7 Ga Fortescue Formation in Pilbara, Western Australia, and I also hope to study the Ediacaran Ouarzazate Formation in Morocco.

Scott Maclennan

Scott MacLennan, Ph.D. Student

I have a keen interest in Archean crustal processes, and at the moment, I’m utilizing ID-TIMS accessory phase (primarily apatite and titanite) thermochronology and zircon geochronology to place temporal and thermal constraints on the evolution of dome and keel structures in the Pilbara craton. These structures are key to our understanding of the thermal state of the continental crust in the Mesoarchean.
I have also started another project trying to place new high resolution zircon geochronological constraints on the stratigraphy of the upper Tambien basin in northern Ethiopia, where a carbonate and siliclastic succession record paleoenvironmental conditions leading up to the Sturtian (~730 Ma) snowball Earth event.

Ayla Pamukcu, Hess Postdoctoral Fellow

I am fascinated by magmas, and my research focuses on the giant volumes of magma involved in rare but enormous supereruptions. I use data from a variety of scales and sources (field relations; rock, crystal, and melt inclusion textures; geochemistry; geochronology; experiments; and modeling) to address questions of when, where, why, and how such magmas are generated, stored, evolve, and erupt. At Princeton, I am studying the 23 Ma Sunshine Peak Tuff and related Lake City caldera (CO, USA), using combined zircon U-Pb geochronology + geochemistry, along with glass and phenocryst geochemistry, to assess volcano-pluton connections and the geometry and architecture of the Lake City magmatic system. Other projects I am currently pursuing include diffusion modeling to understand the interplay between crystal growth and diffusion, and using faceting of olivine-hosted melt inclusions to study magmatic timescales.

Mike Eddy

Mike Eddy, postdoc

I am a geologist that combines detailed fieldwork and geochemical measurements to study a variety of magmatic, tectonic, and paleo-environmental processes. Recently, this has included work on the timescales of magma reservoir assembly and differentiation, constraining the nature of final rifting, tracking basin disruption during triple-junction migration and terrane accretion, and constraining eruption rates in large igneous provinces. Central to all of this work is the production of high-precision U-Pb geochronologic data. At Princeton, I am working to better calibrate eruption rates in the Deccan Traps as well as starting research on a unique magmatic complex that preserves coeval, and likely cogenetic, intrusive and extrusive rocks. The goal of this second project is to link changes in eruptive composition and style to processes that occurred within the fossil magma reservoir.

Dr. Kyle Samperton, former Ph.D. student (now at LLNL)

My research interests focus on the application of high-precision U-Pb geochronology by thermal ionization mass spectrometry (TIMS) toward understanding processes of lithospheric magmatism.   Specifically, I am interested in integrating the temporal, spatial, and chemical data recorded in accessory minerals in order to better constrain the evolution of plutons.   The U-Pb system is capable of resolving geologic events with a precision of 0.1%; coupling this powerful tool with REE and trace element geochemistry can provide valuable insight into the intricacies of igneous petrogenesis.   I am further interested in the development of preparatory and analytical methods for TIMS.

Dr. Brenhin Keller, former Ph.D. student (now at UC Berkeley)

My interests are centered in the fields of geochronology and high-temperature geochemistry, with particular emphasis on integrated accessory phase geochronology and trace element geochemistry. Improvements in U-Pb geochronology have pushed the frontiers of how precisely we can date processes and events in earth's history.  Whether tracing the geochemical evolution of a pluton during emplacement or tracking the trace element evolution of an Archaean craton with 1 Ma precision, the integration high-precision geochronology with geochemical techniques provides fascinating new ways to observe how geological processes unfold over time. 

Dr. Jon Husson, former Ph.D. Student (now at Univ. Wisc. Madison, soon to be asst. prof. at Univ. Victoria, BC)

Deciphering Earth's history through the sedimentary record requires a decidedly multidisciplinary approach. Physics, chemistry, biology, mathematics and modeling can all play important roles. Among the countless questions of earth history, I am currently interested in studying how climate, ocean chemistry and biology interacted to set the stage for the rise of animals. I seek to couple geological field observations and mapping with low-temperature geochemical analyses to help contribute to this question. Additionally, I will also learn techniques of U-Pb geochronology. Absolute dates are vitally important to the study of earth history, as they help to test and constrain our models of evolutionary, chemical and climatic change.

Dr. Mélanie Barboni, former Post-doc, now at UCLA

How magmatic systems operate in the Earth’s crust – magma generation, transport and emplacement – remain challenging questions. My research integrates fieldwork with high-precision U-Pb geochronology by thermal ionization mass-spectrometry (TIMS), major and trace element geochemistry on whole rocks and accessory minerals, and thermal and rheological modeling, to understand the construction mechanisms and thermal evolution of crustal intrusions. I am further interested in understanding the development of mineral phases within magma bodies, in particular investigating the long-debated processes governing K-feldspar megacryst growth. The unparalleled time resolution offered by the TIMS dating on accessory minerals  (precision of 0.1%) coupled to REE and trace element geochemistry give a new, original approach to the K-feldspar megacryst problem, documenting when and at which conditions they formed.