HR: 16:15h
AN: H34A-02    [Abstracts]
TI: Hillslope soils as recording devices in transient landscapes
AU: * Mudd, S M
EM: simon.m.mudd@vanderbilt.edu
AF: Department of Civil and Environmental Engineering, Vanderbilt University, VU Station B 351831 2301 Vanderbilt Place, Nashville, TN 37235 United States
AU: Furbish, D J
EM: david.j.furbish@vanderbilt.edu
AF: Department of Civil and Environmental Engineering, Vanderbilt University, VU Station B 351831 2301 Vanderbilt Place, Nashville, TN 37235 United States
AU: Furbish, D J
EM: david.j.furbish@vanderbilt.edu
AF: Department of Earth and Environmental Sciences, Vanderbilt University, VU Station B #351805 2301 Vanderbilt Place, Nashville, TN 37235 United States
AB: Hillslope soils contain abundant information that can be used to investigate the response of a landscape to transient base level fall. There are two fundamental timescales over which information is stored. When the base level lowering rate of a hillslope changes (usually caused by changes in the rate of channel incision), changes in surface topography, soil depth, and the rate of soil production propagate away from the channel in the upslope direction. The surface topography reacts to these changes over a timescale roughly proportional to the square of the length of the hillslope divided by its diffusivity. Signals of transient incision from channels can take tens of thousands to tens of millions of years to propagate from the channel to the hillcrest; production rates and soil depths will reflect incision rates averaged over increasing timescales as one moves away from the channel. Individual soil particles, on the other hand, moving in the downslope direction, reside on hillslopes over an average timescale that is approximately proportional to the soil depth divided by the average soil production rate. This timescale ranges from thousands to millions of years. Information about climate and soil lowering and mixing rates can be obtained by quantifying the chemistry and mineralogy of hillslope soil particles. We present several examples of the effect of transient base level fall on various properties of hillslope soils (e.g., surface topography, soil depth, soil production, soil chemistry) using both theoretical and numerical models. We demonstrate the utility of using hillslope soils as a repository of information for deciphering the history of transient base level fall in a landscape.
DE: 1807 Climate impacts
DE: 1815 Erosion
DE: 1826 Geomorphology: hillslope (1625)
DE: 1861 Sedimentation (4863)
DE: 1886 Weathering (0790, 1625)
SC: Hydrology [H]
MN: Fall Meeting 2005