Graham W. Lederer, Ph.D.

In my role at the U.S. Geological Survey, I study the supply of materials important to society through materials flow analysis and mineral resource assessment. Materials flow analysis provides a quantitative framework for understanding how mineral resources are transformed into mineral commodities and enter industrial supply chains through processes like primary production, trade, manufacturing, end use, and recycling. Mineral resource assessment involves characterizing mineral deposits and integrating geological, geochemical, and geophysical datasets to better understand how and where minerals resources are concentrated in the Earth.

As a geologist, I am primarily interested in the physical and chemical evolution of the Earth’s crust. My research on ancient and modern orogens focuses on the many processes that create and modify continental crust including deformation, metamorphism, partial melting, and magmatism. Interpreting the spatial and temporal patterns of these petrogenetic processes requires a combination of field- and laboratory-based techniques including detailed structural mapping, microstructural analysis, trace element geochemistry, and accessory phase geochronology. To date, my projects have ranged from characterizing strain in the Grenville basement complex of the Virginia Blue Ridge, constraining the timescales of partial melting in the Himalayan mid-crust through U-Th-Pb dating of syn-tectonic leucogranites, evaluating rare earth phosphate mineralization mechanisms in Proterozoic gneisses of eastern California, and assessing the timing and tempo of large igneous provinces associated with catastrophic changes in Earth history.