Affiliation: | Integrity Solutions, 2900 Lone Oak Pwky., Eagan, Minnesota 55121.;U.S. Geological Survey, 201 W. 8th Street, Pueblo, Colorado 81003.;Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455.;U.S. Geological Survey, 431 National Center, Reston, Virginia 22092. |