HR: 17:15h
AN: H54A-05    [Abstracts]
TI: Sediment budget for Murder Creek, Georgia, USA, from Pu239+240 - determined soil erosion rates
AU: * Stubblefield, A P
EM: aps12@case.edu
AF: Case Western Reserve University, Dept. Geological Sciences 10900 Euclid Ave, Cleveland, OH 44106 United States
AU: Matissoff, G
EM: gxm4@case.edu
AF: Case Western Reserve University, Dept. Geological Sciences 10900 Euclid Ave, Cleveland, OH 44106 United States
AU: Ketterer, M E
EM: Michael.Ketterer@nau.edu
AF: Northern Arizona University, Department of Chemistry and Biochemistry Box 5698, Flagstaff, AZ 86011 United States
AU: Whiting, P J
EM: pjw5@case.edu
AF: Case Western Reserve University, Dept. Geological Sciences 10900 Euclid Ave, Cleveland, OH 44106 United States
AB: Soil inventories of the radionuclides Cs¹³⁷ and Pb²¹⁰ have been used in a variety of environments as indicators for erosion and depositional processes. Development of sediment budgets for entire watersheds from radionuclide data has been somewhat constrained because limited sample numbers may not adequately characterize the wide range of geomorphic conditions and land uses found in heterogeneous environments. The measurement of Pu^239+240 shows great potential for developing quantitative watershed sediment budgets. With inductively-coupled plasma mass spectrometry, hundreds of samples may be processed in dramatically shorter times than the gamma spectrometry method used for Cs¹³⁷ or alpha spectrometry method used for Pb²¹⁰. We collected surface soil samples from Murder Creek in the Piedmont region of Georgia, USA, to compare Pu^239+240 inventories with Cs¹³⁷ and Pb²¹⁰ inventories for a range of land uses in a predominantly forested watershed. Excellent correlations were found for radionuclide inventories (r² =0.88, n = 38) and high resolution (4 mm) depth profiles. The second objective was to generate a sediment budget using the full Pu^239+240 dataset (n = 309). Average Pu^239+240 inventories were 70.0 Bq/m² for hardwood forest, 60.0 Bq/m² for pine plantation, 65.1 Bq/m² for pine forest, 66.7 Bq/m² for row crop agriculture and 67.9 Bq/m² for pasture. The sediment budget will be constructed by converting inventories into site-specific erosion rates. Erosion rates will be scaled up to the watershed scale using GIS coverages of land use, soil, slope, and slope position. Results will be compared with Murder Creek sediment budgets in the scientific literature generated from RUSLE erosion modeling, USGS monitoring networks and reservoir sedimentation.
DE: 1115 Radioisotope geochronology
DE: 1130 Geomorphological geochronology
DE: 1815 Erosion
DE: 1826 Geomorphology: hillslope (1625)
DE: 1879 Watershed
SC: Hydrology [H]
MN: Fall Meeting 2005