Susan L. Brantley, Pennsylvania State University

Recipient of the 2018 Urey Award

Susan L. Brantley is Distinguished Professor of Geosciences in the College of Earth and Mineral Sciences at Pennsylvania State University, where she also is Director of the Earth and Environmental Systems Institute. She has been a member of the faculty at the University since 1986 and director of the Institute since 2003.

Research Statement
“I investigate questions related to the chemistry of natural waters and how these waters create or occlude porosity in rocks and soils. I studied the fundamentals of thermodynamics and kinetics of aqueous geosystems with David Crerar at Princeton University where I measured the kinetics of mineral-water reactions. While working with Art White of the U.S. Geological Survey in Menlo Park California, I began focusing on why reaction rates in the laboratory are faster than in the field. This led me to focus on how rocks transform into soil. To answer these questions, I investigated how micro-organisms, soil gases, erosion, topography, organic and inorganic solutes, rock structure, and climate impact rock weathering reactions. Putting all these observations together resulted in a new discipline – critical zone science, the interdisciplinary science that investigates the entirety of the earth surface layer from the outer limits of vegetation down to ground water. With colleagues including Ray Fletcher, Marina Lebedeva, Jacques Schott, Yves Godderis, Jerome Gaillardet, Peter Lichtner, Carl Steefel, and Li Li, I worked to develop or explore models to describe the interactions of rock, water, gas, and biota while comparing them with observations from hydrology, geomorphology, geochemistry, geology, soil science, and ecology. We have discovered that we can trace biogeochemical reaction fronts in the subsurface to interpret patterns of water flow, water chemistry, and water partitioning in catchments. Such patterns can also be related across scales from the mineral grain to watersheds. Most recently, I have become interested in the giant rock-water experiment begun in 2004 in Pennsylvania: hydraulic fracturing of the Marcellus shale formation. By working with large water quality datasets we are learning how this new industry impacts water resources, but we are also discovering the important geological controls on natural water chemistry at regional scales.”