Difference between revisions of "Connections between rock mass strength and grain size in alluvium"
(Created page with "The sensitivity of fluvial erosion to rock damage Roy, S.G.; Tucker, G.E.; Koons, P.O.; Smith, S.M.; Upton, P. 0. Abstract We explore two ways in which the rheological propert...") |
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Roy, S.G.; Tucker, G.E.; Koons, P.O.; Smith, S.M.; Upton, P. | Roy, S.G.; Tucker, G.E.; Koons, P.O.; Smith, S.M.; Upton, P. | ||
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We explore two ways in which the rheological properties of rock potentially influence fluvial incision of rock and transport of sediments across a landscape: 1) rock erodibility is inversely proportional to rock strength, and 2) fracture density influences the initial grain sizes produced upon erosion. Fault damage zones show these effects particularly well because of the sharp strength and texture gradients associated with localized shear abrasion. Surface runoff is attracted by the rapid erosion and transport of fault gouge, causing high order channels to become confined within the structure of fault damage zones. Erosion of adjacent, intact bedrock produces relatively coarser grained gravels that accumulate in the low relief of the damage zone. In our numerical experiments, sediment thickness in the damage zone depends on 1) the degree of shear abrasion, which determines the rock erodibility gradient and the texture gradient transported by runoff, and 2) the amplitude and frequency of storm events, which determine the carrying capacity of accumulated runoff. The prevalence of features that impose strength and texture heterogeneity on the Earth’s surface exert significant controls on the rates and patterns of erosion, and it will be important to recognize the role of heterogeneity in future studies of landscape evolution. | We explore two ways in which the rheological properties of rock potentially influence fluvial incision of rock and transport of sediments across a landscape: 1) rock erodibility is inversely proportional to rock strength, and 2) fracture density influences the initial grain sizes produced upon erosion. Fault damage zones show these effects particularly well because of the sharp strength and texture gradients associated with localized shear abrasion. Surface runoff is attracted by the rapid erosion and transport of fault gouge, causing high order channels to become confined within the structure of fault damage zones. Erosion of adjacent, intact bedrock produces relatively coarser grained gravels that accumulate in the low relief of the damage zone. In our numerical experiments, sediment thickness in the damage zone depends on 1) the degree of shear abrasion, which determines the rock erodibility gradient and the texture gradient transported by runoff, and 2) the amplitude and frequency of storm events, which determine the carrying capacity of accumulated runoff. The prevalence of features that impose strength and texture heterogeneity on the Earth’s surface exert significant controls on the rates and patterns of erosion, and it will be important to recognize the role of heterogeneity in future studies of landscape evolution. | ||
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Revision as of 04:47, 13 March 2015
The sensitivity of fluvial erosion to rock damage
Roy, S.G.; Tucker, G.E.; Koons, P.O.; Smith, S.M.; Upton, P.
0. Abstract
We explore two ways in which the rheological properties of rock potentially influence fluvial incision of rock and transport of sediments across a landscape: 1) rock erodibility is inversely proportional to rock strength, and 2) fracture density influences the initial grain sizes produced upon erosion. Fault damage zones show these effects particularly well because of the sharp strength and texture gradients associated with localized shear abrasion. Surface runoff is attracted by the rapid erosion and transport of fault gouge, causing high order channels to become confined within the structure of fault damage zones. Erosion of adjacent, intact bedrock produces relatively coarser grained gravels that accumulate in the low relief of the damage zone. In our numerical experiments, sediment thickness in the damage zone depends on 1) the degree of shear abrasion, which determines the rock erodibility gradient and the texture gradient transported by runoff, and 2) the amplitude and frequency of storm events, which determine the carrying capacity of accumulated runoff. The prevalence of features that impose strength and texture heterogeneity on the Earth’s surface exert significant controls on the rates and patterns of erosion, and it will be important to recognize the role of heterogeneity in future studies of landscape evolution.
