Available in-person--Harshbarger 110--and via Zoom webinar. Contact the department to subscribe to the email list (zoom link provided in announcement).
This talk explores open questions and recent findings about the co-evolution of water, rock and microbial life at kilometers-depth in the earth's crust (hypo-critical zone) over geologic timescales. New results from water, rock and microbial samples and hydrologic modeling across the Colorado Plateau show periods of deep burial, sterilization of microbial communities, and stagnation/retention of saline fluids in sedimentary rocks at depth. Recent, rapid incision of the Colorado River (<~4-6 Ma) eroded confining units and brought sediments closer to the surface in contact with circulating meteoric waters, flushing saline fluids and re-introducing microbial communities under cooler temperatures. These microbial communities have extensively cycled carbon (i.e., degraded oil and thermogenic gas and generated microbial methane) within the last few million years. These results have implications for extraction of critical resources (e.g., Li, He), storage of energy waste products (e.g., CO2, spent nuclear fuel), and extent of groundwater resources, in addition to providing insights into potential signatures for and history of life on other planets.
Jennifer McIntosh is a Professor and University Distinguished Scholar in the Department of Hydrology and Atmospheric Sciences at the University of Arizona (UArizona) and Joint Faculty member in the UArizona Department of Geosciences. She also held and Adjunct Research Geologist position with the United States Geological Survey from 2007-2017, and is currently an Adjunct Professor at the University of Saskatchewan in the Department of Civil and Geological Engineering. McIntosh is a Fellow of the Geological Society of America and the Canadian Institute for Advanced Research (CIFAR) Earth 4D: Subsurface Science and Exploration Program. McIntosh received a BA in geology-chemistry from Whitman College, a MS, and a PhD from the University of Michigan (2004), and the Morton K. and Jane Blaustein Postdoctoral Fellowship at Johns Hopkins University in Earth and Planetary Sciences. McIntosh is a hydrogeochemist who works at the interface of hydrology, geochemistry, and microbiology to understand micro (pore) to macro (continental scale) processes throughout the Earth's crust. She has received numerous awards for her research, teaching, and student mentoring, including the USGS Star Award, the UArizona Distinguished Scholar Award, Blitzer (teaching) Award for physics-related sciences. She regularly serves as a technical expert for the US EPA, National Academies of Science and Engineering, and Nuclear Waste Technical Review Board. Her students and postdocs have gone on to positions in academia, government agencies, and environmental consulting.
Dr. Jennifer McIntosh, UA Distinguished University Scholar and Professor, Hydrology and Atmospheric Sciences, and UA Joint Professor, Geosciences [Email: email@example.com | Google Scholar | Research Gate]