Current Research

The Aqueous Geochemistry and Mineralogy Group studies geochemical processes controlling mineral transformations and the fate of trace elements, nutrients, and contaminants in terrestrial and planetary aquatic systems.  Our current work focuses on topics of relevance to environmental geochemistry and astrobiology.  A summary of our current research projects is listed below.

ENVIRONMENTAL GEOCHEMISTRY RESEARCH

Structural and Interfacial Geochemistry of Rare Earth and Platinum Group Elements
Funded by the Department of Energy
Collaborators: Prof. Daniel Giammar (Wash. U.), Dr. Eugene Ilton (PNNL), Dr. Eric Bylaska (PNNL)
Current Participants: Yihang Fang, Yanting Qin, Emily Wright

Critical elements are essential to key technologies that underlie energy storage and generation, transportation, communications, and computing. The availability of the rare earth elements (REEs) and the platinum group elements (PGEs) are of particular concern because of the lack of adequate U.S. domestic production and, especially for PGEs, their overall low abundance in Earth’s crust. REEs and PGEs in deposits formed by rock weathering represent new potential resources for future exploitation. However, the fundamental geochemical processes that dictate the migration and enrichment of REEs and PGEs during weathering are poorly constrained. The mechanisms controlling how REEs and PGEs bind to the surfaces of mineral, become trapped inside the structures of minerals, and are mobilized from mineral surfaces and structures in weathering environments represent major areas of uncertainty. The foundational scientific knowledge required to accurately predict the formation and occurrence of deposits of REEs and PGEs formed via weathering is currently inadequate. This project seeks to elucidate the roles of mineral surfaces and structures in controlling the migration and enrichment of REEs and PGEs in weathering environments. Through coordinated laboratory experiments, synchrotron-based X-ray techniques, and advanced computational studies, this project will obtain fundamental new insight into the basic chemical processes controlling the formation of rare earth and platinum group element deposits near Earth’s surface.

Biogeochemical Processes Affecting Critical Mineral Hosts in Mine Tailings and Weathered Ore Zones
Funded by the National Science Foundation
Current Participants: Emily Wright

New domestic resources of critical minerals are needed to support a sustainable economy. Rare earth elements are necessary for magnets in electric motors and wind turbines while platinum group elements are essential for catalytic converters on vehicles and for advanced chemical processing, but both resources are primarily obtained from foreign sources. Mine waste rocks represent promising hosts for rare earth elements, enabling reuse of materials already removed from the ground. Similarly, zones of ore rocks exposed at Earth’s surface and materials washed into nearby streams represent potential new sources of platinum group elements. The availability of critical minerals in this resource types, and the ability to extract them, are uncertain because these materials have been weathered by the action of sun, wind, and rain. This project will investigate how weathering affects critical minerals in mine wastes and exposed ore zones at three different locations in the United States.

Heavy Metal Hazard and Soil Quality in Peace Park, St. Louis
Funded by Washington University
Current Participants: Elaine Flynn
Partners: Green City Coalition, St. Louis Development Corporation, The Nature Conservancy, Missouri Department of Conservation

Unoccupied land in the College Hill neighborhood of St. Louis is being repurposed to create a new place for the community to gather for events, entertainment, and recreation. The planned Peace Park seeks to health, well-being, and overall landscape of this community. We are working to assess soil heavy metal hazards that may exist in the vacant urban land that is the home for Peace Park and also assessing aspects of soil health to aid in implementing the park design and maintenance.

ASTROBIOLOGY RESEARCH

Reconciling Prebiotic Paradigms: Mapping Planetary Reality onto Experimental Strategies
Funded by the National Aeronautics and Space Administration
Current Participants: Emily Millman
Collaborators: Prof. Karyn Rogers (RPI) plus 14 other scientists at multiple institutions
Project Website: http://earthfirstorigins.rare.rpi.edu/

The large collaborative project consists of one of the major teams involved in NASA's Prebiotic Chemistry and Early Earth Environments Consortium supported by the NASA Astrobiology Program. The overarching goal is to develop a new understanding of conditions on the early Earth and the prebiotic chemistry that occurred with rocks, minerals, and fluids actually present during this period. The Washington University team is specifically focused on phyllosilicates that formed on the early Earth from mafic and ultramafic crystal alteration and how key prebiotic compounds bound to and were selectively concentrated by these phases.