HR: 10:55h
AN: V52C-03    [Abstracts]
TI: Chlorofluorocarbon and Tritium Concentration in Springs in the Norris Geyser Basin Area: Constraining Circulation Rate, Mixing Processes, and Ground-Water Evolution of Locally Derived Ground-Water in Yellowstone National Park, USA.
AU: * Gardner, P
EM: wgardner@geophys.utah.edu
AF: University of Utah Dept. of Geology and Geophysics, 135 S. 1460 East Rm 714, Salt Lake City, UT 84112, United States
AU: Susong, D
EM: ddsusong@usgs.gov
AF: Utah Water Science Center United States Geological Survey, 2329 W. Orton Circle, Salt Lake City, UT 84119, United States
AU: Solomon, K
EM: ksolomon@mines.utah.edu
AF: University of Utah Dept. of Geology and Geophysics, 135 S. 1460 East Rm 714, Salt Lake City, UT 84112, United States
AU: Heasler, H
EM: Henry_Heasler@nps.gov
AF: Yellowstone National Park National Park Service, Yellowstone National Park, Mammoth, WY 82190,
AB: Chlorofluorocarbon (CFC) and tritium concentrations were measured in cool to warm springs in the Norris area of Yellowstone National Park to constrain the scale and rate of circulation within the shallow, local ground-water system and investigate interactions between locally derived water and the geothermal system. Water from more than 65 springs in and surrounding the Norris Geyser Basin, varying in temperature from 3°C to 90°C, was sampled and analyzed for CFC-11, CFC-12, CFC-113, and tritium. Apparent CFC age was calculated by using noble gas recharge temperature and the elevation of the surrounding volcanic flows. Measured tritium content ranged from 1 to 14 tritium units and apparent CFC age ranged from 1965 to modern. Tritium values were corrected for decay during transport by using the apparent CFC age, yielding the CFC age corrected initial tritium content. Initial tritium concentrations were then compared to an interpolated tritium precipitation curve for Yellowstone National Park, that has been smoothed via transport in the subsurface over a characteristic length scale. CFC ratio analysis shows no evidence of large-scale mixing, or systematic contamination or degradation. CFC age-corrected initial tritium contents match the historical input curve within the uncertainty of the input function, further indicating lack of large-scale mixing, and viability of CFC ages. These results imply that a large volume of ground water in the Norris Geyser Basin area is relatively young and likely recharged within the park.
DE: 1012 Reactions and phase equilibria (3612, 8412)
DE: 1040 Radiogenic isotope geochemistry
DE: 1829 Groundwater hydrology
DE: 8424 Hydrothermal systems (0450, 1034, 3017, 3616, 4832, 8135)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting