Title:
Evolution of subsurface fluid-rock-microbial systems over geologic timescales Abstract:
Our understanding of how complex subsurface porous and fractured rock, fluid, and microbe systems are coupled and have dynamically evolved over geologic time is limited. Yet, this knowledge is necessary for effective subsurface resource and waste management over millennial timescales. Fundamental questions include: How do changes at the land surface alter fluid flow, fluid-rock reactions, and microbial activity at kilometers depth in the earth’s crust? How do these reactions and biological activity alter porosity and permeability distributions? And, what evidence of past microbial activity and associated fluid flow and fluid-rock reactions are recorded in minerals precipitated in pore spaces? This talk will highlight recent work on the distribution of permeability and porosity at global-scales and zoom-in to regional- to pore-scale examples of how subsurface microbe-rock-fluid systems have evolved across the Colorado Plateau in response to changes in geologic and hydrologic forcings (e.g., deep burial of sediment versus recent denudation from downcutting of the Colorado River and influx of fresh water). Implications for these findings on the accumulation versus flushing (and/or biological removal) of Lithium-rich brines, helium, hydrogen, and carbon dioxide from pore spaces will also be discussed. Bio:
Jennifer McIntosh is the Thomas Meixner Endowed Chair, Professor, University Distinguished Scholar, and Associate Department Head of Hydrology and Atmospheric Sciences at the University of Arizona (UA). 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 her PhD in Geology from the University of Michigan (2004) and was the Morton K. and Jane Blaustein Postdoctoral Fellow at Johns Hopkins University in Earth and Planetary Sciences (2004-2006). She has published over 120 papers on the geochemistry of geochemistry of fresh to saline fluids to constrain sources, residence times, biogeochemical reactions, and flowpaths of waters, solutes, and gases in the earth’s shallow crust; and regularly serves as a technical expert for the US EPA, National Academies of Sciences, Nuclear Waste Technical Review Board, International Atomic Energy Agency, and UK Royal Society. |
