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Sediment flux on transport-limited hillslopes is well known to vary nonlinearly with slope, diverging as the angle of stability is approached. To date, however, no study has validated the precise form of the nonlinear slope-dependent transport model over geologic time scales in a non-steady-state landform. In this paper, we show how cinder cones can be used to validate the nonlinear transport model using Lathrop Wells cinder cone in Nye County, Nevada, as a type example. Cinder cones are well suited for this purpose because they can be radiometrically dated and their angles of stability can be constrained by measurement of subsurface contacts between primary fallout and overlying colluvial deposits reworked from upslope. Forward model results with a generalized, nonlinear transport model characterized by diffusivity, κ, and nonlinear exponent, n, show that the evolution of the cone rim and base are most sensitive to κ, while the cone midpoint is most sensitive to n. Analyses of the full cone shape, therefore, permit the two model parameters to be independently inferred if the cone age and angle of stability are independently known. Results for Lathrop Wells imply that n = 2 in the generalized, nonlinear transport model, which is consistent with Roering et al.'s (1999) widely used form of that model. [ABSTRACT FROM AUTHOR]

We used 10Be and 26Al to constrain the millennial-scale sediment and nuclide budget for a common, long-studied, but poorly understood landform in arid regions, the desert piedmont. We sampled the Chemehuevi Mountain piedmont, a complex multisurfaced landform in the Mojave Desert, western United States. The nuclide data indicate that sediment is produced more rapidly (1.1 × 105 kg·yr-1·.km-2) in steep mountain source basins than on the low-gradient pediment (4.0 × 104 kg·yr-1·km-2) or the intrapiedmont mountain range (2.5 × 104 kg·yr-1·km-2). However, the bulk of the sediment in transport is derived from erosion of the large abandoned alluvial surface (3.9 × 104 kg·yr-1·km-2). The combination of mass and nuclide budgeting suggests that sediment transport speeds decrease downslope from tens of meters per year in confined channels on the proximal pediment to decimeters per year in unconfined distributaries on distal wash surfaces. The sediment and nuclide budgeting approach we use is particularly valuable in arid regions where geomorphically significant events are infrequent and dating control is poor, thus confounding traditional sediment-budgeting techniques. [ABSTRACT FROM AUTHOR]