Presented By:
Dr. Carol Finn, Ph.D.
United State Geological
Denver, CO
Abstract:The nature of Yellowstone National Park’s plumbing system linking deep thermal fluids to its legendary thermal features is virtually unknown. The prevailing concepts of Yellowstone hydrology and chemistry are that fluids reside in reservoirs with unknown geometries, flow laterally from distal sources and emerge at the edges of lava flows. Here we present a high-resolution synoptic view of pathways of the Yellowstone hydrothermal system derived from electrical resistivity and magnetic susceptibility models of airborne geophysical data5,6. Groundwater and thermal fluids containing appreciable total dissolved solids significantly reduce resistivities of porous volcanic rocks and are differentiated by their resistivity signatures7. Clay sequences mapped in thermal areas8,9 and boreholes10 typically form at depths of less than 1,000 metres over fault-controlled thermal fluid and/or gas conduits. We show that most thermal features are located above high-flux conduits along buried faults capped with clay that has low resistivity and low susceptibility. Shallow subhorizontal pathways feed groundwater into basins that mixes with thermal fluids from vertical conduits. These mixed fluids emerge at the surface, controlled by surficial permeability, and flow outwards along deeper brecciated layers. These outflows, continuing between the geyser basins, mix with local groundwater and thermal fluids to produce the observed geochemical signatures. Our high-fidelity images inform geochemical and groundwater models for hydrothermal systems worldwide.
This Webinar is Approved for 1 New York State PDH Credit
*Bio: Carol Finn is a research geophysicist with the United States Geological Survey's Geology, Geophysics and Geochemistry Science Center in Denver, CO. Carol specializes in the application of magnetic, gravity and electromagnetic data, to develop framework geological models in support of resource and volcano hazards assessments and fundamental Earth Processes. She has worked all over the world. Her current research is on imagining Yellowstone's iconic thermal features, 3D modeling of layered mafic intrusions and their platinum group element potential and Cascades and Alaska landslide hazards. Carol is an expert on the application of magnetic, gravity and electromagnetic data, along with other geophysical techniques, to identify the subsurface distribution of:
Professional Experience
1978-present, U.S. Geological Survey, Denver, CO
E-mail: cfinn@usgs.gov
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