Calibration and testing of upland hillslope evolution models in a dated landscape: Banco Bonito, New Mexico

Abstract

[1] In this study we tested upland hillslope evolution models and constrained the rates of regolith production, colluvial transport, and eolian deposition over geologic time scales in a dated volcanic landscape in northern New Mexico using field measurements of regolith thickness; geochemical analyses of regolith, bedrock, and regional dust; numerical modeling of regolith production and transport; and quantitative analyses of airborne light detection and ranging (lidar) digital elevation models (DEMs). Within this volcanic landscape, many topographically closed basins exist as a result of compressional folding and explosion pitting during eruption. The landscape has evolved from an initial state of no regolith cover at 40 ± 5 ka to its modern state, which has highly weathered regolith ranging from 0 to 3+ m, with local thickness values controlled primarily by topographic position. Our models constrain the maximum rate of regolith production in the study area to be in the range of 0.02 to 0.12 m kyr −1 and the rate of colluvial transport per unit slope gradient to be in the range of 0.2 to 2.7 m 2 kyr −1, with higher values in areas with more aboveground biomass. We conclude that a depth-dependent colluvial transport model better predicts the observed spatial distribution of regolith thickness compared to a model that has no depth dependence. This study adds to the database of estimates for rates of regolith production and transport in the western United States and shows how dated landscapes can be used to improve our understanding of the coevolution of landscapes and regolith cover.

Coevolution of nonlinear trends in vegetation, soils, and topography with elevation and slope aspect: A case study in the sky islands of southern Arizona

“…An alternative approach is to assume that the flux is proportional to the soil thickness measured normal to the tangent of the slope for relatively thin soils (i.e., less than ~1 m): where κ d has units of length 1 time −1 [ Furbish et al ., ; Roering , ]. In this paper, we adopt equation () to model the colluvial sediment flux based on the fact that depth‐dependent transport has been shown to lead to more accurate predictions of soil thickness in well‐constrained field cases [e.g., Heimsath et al ., ; Pelletier et al ., ]. The coupling between soil thickness and colluvial sediment transport is included via the h dependence on the right side of equation ().…”

Influence of lithology on hillslope morphology and response to tectonic forcing in the northern Sierra Nevada of California

“…Properties of the canopy elevation structure such as the mean and standard deviation of the height of canopy returns ( V mean and V sd , respectively) can be readily extracted from LiDAR [e.g., Nilsson , ; Naesset , ; Lefsky et al ., ; Holmgren et al ., ; Donoghue and Watt , ] and may provide useful indicators of AGB [e.g., Hall et al ., ; Clark et al . ; Pelletier et al ., ; Saatchi et al ., ]. Clark et al .…”

“…Pelletier et al . [] used a 1 m resolution canopy height map derived from LiDAR to demonstrate a negative relationship between mean C HT and V mean , suggesting that vegetation cover may be controlling the sediment transport coefficient D .…”

How does grid-resolution modulate the topographic expression of geomorphic processes?

“…Roering (2008) and Hurst et al (2012) demonstrated that hilltop curvature scales with erosion rate and as such demonstrated the importance of accurately constraining the impact of grid resolution on this landscape parameter. Its importance is highlighted by an increasing number of studies using this relationship as a proxy for erosion rate (Pelletier et al, 2011;Hurst et al, 2013c, b;Grieve et al, 2016b). Hilltop curvature can also be used to constrain the sediment transport coefficient of a landscape where an independent constraint on erosion rate is available (Hurst et al, 2013c).…”

“…Roering et al (2007) and Hurst et al (2012) demonstrated that the curvature of ridgelines measured from high-resolution topography can be used as a proxy for erosion rates in soil-mantled landscapes. This observation has been used in many studies in which cosmogenic radionuclide-derived erosion rates are unavailable (Pelletier et al, 2011;Hurst et al, 2013c, b;Grieve et al, 2016b). However, it can also be used in locations with an independent constraint on erosion rates in order to quantify a sediment transport coefficient that relates hillslope sediment flux to the topographic gradient, which is set by the material properties of soils (Furbish et al, 2009).…”