I identify as an igneous and metamorphic petrologist, and an isotope geochemist. Most of my research relates to mass transfer and processing in subduction zones. I am interested in all aspects of subduction - from sediment ingestion into the trench, to the metamorphic reactions (especially dehydration reactions) that take place in the downgoing slab, to mantle metasomatism and melting, to the magmatic and volcanic processes taking place at all depths in the arc crust. Beyond subduction-related processes, I am also interested in large mafic igneous provinces including Iceland and the Bushveld / Rustenburg Layered Suite. Recently, I have been dabbling in critical element resources in Pennsylvania including lithium, cobalt, and rare earth elements.

Current Research / Funded Projects:
E-FIRE (ExTerra Field Institutes and Research Endeavor) Partnership for International Research and Education. The E-FIRE project, now nearing completion, funded 11 PhD students and postdoctoral scholars at US institutions to conduct field work in the Western Alps and Voltri Massif (France and Italy) in collaboration with European partners. The scientific themes of this project included fluid transfer, reaction timescales, and rheological properties of materials at the slab interface and mantle regions of a fossil subduction zone.

• Boron loss and isotopic fractionation as a tracer of fluid loss during sediment subduction and dehydration in Southwest Japan. In collaboration with colleagues at UT Austin and Tohoku University, we are investigating the progressive metamorphism of sediments from deposition at the seafloor to breakdown at sub-arc depths using samples from the Nankai Trough, Shimanto Shale, and Sanbagawa Schist units. We are also looking at the timing of peak metamorphism and exhumation rates for the Sanbagawa Schist.
• GeoPEERS (Geosciences Program in Energy and Environmental Resource Sustainability) Research Experience for Undergraduates. This program aims to prepare the next generation geoscience workforce by providing participants with the skills to approach natural resource exploration and development, environmental science, environmental justice, climate change, and sustainable development as one integrated system.
• Dean’s Fund Postdoc “Decolonizing the 40th Parallel”. The goal of this project is to make Geosciences Field Camp more inclusive and introspective by developing a co-curriculum around exploration and exploitation, Westward Expansion, extractive scientific practices, and the cultural, historical, and scientific importance of mapping.

I study sedimentary rocks and volcanic deposits to learn about continental rifting process, and the timing and geologic setting of early human evolution. Broadly, my current and ongoing research can be split into three themes: the geologic context for early human evolution; extensional faulting and basin development; and magmatic evolution of explosive volcanism in rift zones. This work is focused in eastern Africa and it is highly collaborative. I working closely with paleontologists and archaeologists among others.

• Geochemical correlations of tephra deposits in Afar, Ethiopia for human origins studies. This project also involves stratigraphic analysis to interpret depositional environments and structural geology looking at rift development.
• Dating, geochemistry, and stratigraphy of ~5-6-million-year-old paleontological sites near Narok, Kenya.
• Geomorphology of the lower Awash, Afar Ethiopia using cosmogenic radionuclides.
• Building an explosive volcanic geochemical database for eastern Africa (EARThD) in collaboration with NSF/IEDA.

Our EGG group is dedicated to improving the physical imaging of near-surface geology structure and its physical properties using quantitative geophysical methods (seismic and ground-penetrating radar).

Current projects include:

• Imaging sequestrated CO2
• Fiber-optic for environment senseing (FORESEE)
• Seismic wave attenuation & Q full waveform inversion
• Micro-earthquake source imaging and tracking
• GPR

Fossil plants tell the story of our green planet’s evolution and reveal its landscapes from deep time to present. They are also extremely sensitive indicators of past climates, plant-insect interactions, biodiversity, and the effects of significant environmental disturbances. These data provide deep-time analogs that uniquely illuminate modern ecosystems and their possible responses to anthropogenic change. My temporal focus is the latest Cretaceous through middle Eocene, ~67-45 million years ago (Ma), an interval characterized by global disturbances that are closely spaced in geologic time. These include latest Cretaceous warming and cooling (68-66 Ma), the end-Cretaceous mass extinction (66 Ma), ensuing recovery during the Paleocene (66-56 Ma), and both abrupt and long-term warming across the Paleocene-Eocene boundary (56 Ma). I enjoy collaborations with numerous colleagues worldwide and a terrific lab group, with whom I do extensive fieldwork, concentrated currently in Patagonia, Argentina, and increasingly in SE Asia. Here are highlights of two current projects, and more are listed here.

Origins of Southeast Asian Rainforests from Paleobotany and Machine Learning

This cutting-edge NSF project is underway in collaboration with Dr. Thomas Serre’s machine-learning lab at Brown, Dr. Maria Gandolfo’s paleobotany lab at Cornell, and numerous collaborators at MEF in Argentina and in several more countries including China, India, Australia, Vietnam, Indonesia, and Brunei. We aim to develop the powerful tools of machine learning to identify fossil leaves and shed a powerful new light on the evolution of SE Asia’s extremely biodiverse and threatened rainforests. We are making and using extensive fossil collections from SE Asia and diverse areas that have contributed to the flora through plate movements over geologic time.

Patagonia Paleofloras Project

The fossil record of life on land predominantly comes from the Northern Hemisphere. However, the outstandingly rich, relatively little-known fossil beds of Patagonia, southern Argentina, provide an unrivaled opportunity to learn whether life responded differently to mass extinction, plate tectonics, and past climate change on the other side of the world. This multinational NSF project intensively samples and analyzes fossil plants and animals from Patagonia through about 20 million years, from just before the end-Cretaceous dinosaur extinction (66 million years ago), through the early recovery period and the Eocene warming interval. Through groundbreaking field discoveries, comprehensive collections, and state-of-the-art lab techniques, this research is transforming understanding of the origins of the Southern Hemisphere’s floras and biomes, the role of Patagonia, and the legacy of surviving living fossils now located in vulnerable rainforest areas as far away as Southeast Asia (see above). A Google Scholar page lists our >135 publications.