Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California

The potential soil production rate, i.e., the upper limit at which bedrock can be converted into transportable material, limits how fast erosion can occur in mountain ranges in the absence of widespread landsliding in bedrock or intact regolith. Traditionally, the potential soil production rate has...

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Main Author: Pelletier, Jon D.
Other Authors: Univ Arizona, Dept Geosci
Language:en
Published: COPERNICUS GESELLSCHAFT MBH 2017
Online Access:http://hdl.handle.net/10150/626605
http://arizona.openrepository.com/arizona/handle/10150/626605
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spelling ndltd-arizona.edu-oai-arizona.openrepository.com-10150-6266052018-02-17T03:00:29Z Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California Pelletier, Jon D. Univ Arizona, Dept Geosci The potential soil production rate, i.e., the upper limit at which bedrock can be converted into transportable material, limits how fast erosion can occur in mountain ranges in the absence of widespread landsliding in bedrock or intact regolith. Traditionally, the potential soil production rate has been considered to be solely dependent on climate and rock characteristics. Data from the San Gabriel Mountains of California, however, suggest that topographic steepness may also influence potential soil production rates. In this paper I test the hypothesis that topographically induced stress opening of preexisting fractures in the bedrock or intact regolith beneath hillslopes of the San Gabriel Mountains increases potential soil production rates in steep portions of the range. A mathematical model for this process predicts a relationship between potential soil production rates and average slope consistent with published data. Once the effects of average slope are accounted for, a small subset of the data suggests that cold temperatures may limit soil production rates at the highest elevations of the range due to the influence of temperature on vegetation growth. These results suggest that climate and rock characteristics may be the sole controls on potential soil production rates as traditionally assumed but that the porosity of bedrock or intact regolith may evolve with topographic steepness in a way that enhances the persistence of soil cover in compressive-stress environments. I develop an empirical equation that relates potential soil production rates in the San Gabriel Mountains to the average slope and a climatic index that accounts for temperature limitations on soil production rates at high elevations. Assuming a balance between soil production and erosion rates on the hillslope scale, I illustrate the interrelationships among potential soil production rates, soil thickness, erosion rates, and topographic steepness that result from the feedbacks among geomorphic, geophysical, and pedogenic processes in the San Gabriel Mountains. 2017-08-24 Article Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California 2017, 5 (3):479 Earth Surface Dynamics 2196-632X 10.5194/esurf-5-479-2017 http://hdl.handle.net/10150/626605 http://arizona.openrepository.com/arizona/handle/10150/626605 Earth Surface Dynamics en https://www.earth-surf-dynam.net/5/479/2017/ © Author(s) 2017. This work is distributed under the Creative Commons Attribution 3.0 License. COPERNICUS GESELLSCHAFT MBH
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language en
sources NDLTD
description The potential soil production rate, i.e., the upper limit at which bedrock can be converted into transportable material, limits how fast erosion can occur in mountain ranges in the absence of widespread landsliding in bedrock or intact regolith. Traditionally, the potential soil production rate has been considered to be solely dependent on climate and rock characteristics. Data from the San Gabriel Mountains of California, however, suggest that topographic steepness may also influence potential soil production rates. In this paper I test the hypothesis that topographically induced stress opening of preexisting fractures in the bedrock or intact regolith beneath hillslopes of the San Gabriel Mountains increases potential soil production rates in steep portions of the range. A mathematical model for this process predicts a relationship between potential soil production rates and average slope consistent with published data. Once the effects of average slope are accounted for, a small subset of the data suggests that cold temperatures may limit soil production rates at the highest elevations of the range due to the influence of temperature on vegetation growth. These results suggest that climate and rock characteristics may be the sole controls on potential soil production rates as traditionally assumed but that the porosity of bedrock or intact regolith may evolve with topographic steepness in a way that enhances the persistence of soil cover in compressive-stress environments. I develop an empirical equation that relates potential soil production rates in the San Gabriel Mountains to the average slope and a climatic index that accounts for temperature limitations on soil production rates at high elevations. Assuming a balance between soil production and erosion rates on the hillslope scale, I illustrate the interrelationships among potential soil production rates, soil thickness, erosion rates, and topographic steepness that result from the feedbacks among geomorphic, geophysical, and pedogenic processes in the San Gabriel Mountains.
author2 Univ Arizona, Dept Geosci
author_facet Univ Arizona, Dept Geosci
Pelletier, Jon D.
author Pelletier, Jon D.
spellingShingle Pelletier, Jon D.
Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California
author_sort Pelletier, Jon D.
title Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California
title_short Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California
title_full Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California
title_fullStr Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California
title_full_unstemmed Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California
title_sort quantifying the controls on potential soil production rates: a case study of the san gabriel mountains, california
publisher COPERNICUS GESELLSCHAFT MBH
publishDate 2017
url http://hdl.handle.net/10150/626605
http://arizona.openrepository.com/arizona/handle/10150/626605
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