HR: 17:30h
AN: GC54A-07    [Abstracts]
TI: Implications of Soil Gas Survey Results Over Known Carbon Dioxide Systems for Long-term Monitoring
AU: Allis, R
EM: rickallis@utah.gov
AF: Utah Geological Survey, 1594 W. North Temple, Salt Lake City, UT 84114 United States
AU: Bergfeld, D
EM: dbergfel@usgs.gov
AF: United States Geological Survey, 329 Orton Circle, West Valley City, UT 84119 United States
AU: Moore, J
EM: jmoore@egi.utah.edu
AF: Energy and Geoscience Institute, University of Utah, Salt Lake City, UT 84108 United States
AU: Heath, J
EM: jheath@nmt.edu
AF: New Mexico Institute of Mining and Technology, Hydrology Program, Socorro, NM 87801 United States
AU: * McPherson, B J
EM: brian@nmt.edu
AF: New Mexico Institute of Mining and Technology, Hydrology Program, Socorro, NM 87801 United States
AB: Soil gas surveys have been carried out over three areas with natural occurrences of carbon dioxide on the Colorado Plateau. At Farnham Dome, Utah, and Springerville-St. Johns, Arizona, carbon dioxide reservoirs occur at 600 - 800 m depth, but no anomalous soil gas carbon dioxide flux was detected. Evidence of widespread vein calcite at the surface (Farnham Dome) and travertine deposits (Springerville-St. Johns) suggest that the fields may have leaked carbon dioxide-rich fluids in the past. At Springerville-St. Johns, there is a significant outflow of high-bicarbonate water to the surface, which may be the main mechanism that carbon dioxide is reaching the surface today. carbon dioxide fluxes as high as 40 g m-2 day-1 in swampy ground adjacent to bicarbonate spring outflows at Springerville-St. Johns are attributed to shallow soil reactions rather than to a deep upflow. A 500 m depth, non-producing well at Springerville-St. Johns responds barometrically, sucking in air during pressure highs, and discharging a carbon dioxide-air mixture during pressure lows. Results from a third soil gas survey area of natural carbon dioxide-water discharges along fault zones in central Utah will also be presented. The unexpected results indicate that soil gas monitoring may not be easy or simple.
DE: 1694 Instruments and techniques
DE: 1699 General or miscellaneous
SC: Global Climate Change [GC]
MN: 2004 AGU Fall Meeting