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Cosmogenic 21 Ne analysis of individual detrital grains: Opportunities and limitations
Author(s) -
Codilean Alexandru T.,
Bishop Paul,
Hoey Trevor B.,
Stuart Finlay M.,
Fabel Derek
Publication year - 2010
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.1815
Subject(s) - cosmogenic nuclide , geology , erosion , bedrock , sediment , drainage basin , denudation , fluvial , range (aeronautics) , spatial distribution , geomorphology , lithology , nuclide , sediment transport , hydrology (agriculture) , structural basin , geochemistry , paleontology , physics , cosmic ray , remote sensing , geotechnical engineering , quantum mechanics , astrophysics , geography , composite material , materials science , cartography , tectonics
We use a numerical model describing cosmogenic nuclide acquisition in sediment moving through the upper Gaub River catchment to evaluate the extent to which aspects of source area geomorphology and geomorphological processes can be inferred from frequency distributions of cosmogenic 21 Ne ( 21 Ne c ) concentrations in individual detrital grains. The numerical model predicts the pathways of sediment grains from their source to the outlet of the catchment and calculates the total 21 Ne c concentration that each grain acquires along its pathway. The model fully accounts for variations in nuclide production due to changes in latitude, altitude and topographic shielding and allows for spatially variable erosion and sediment transport rates. Model results show that the form of the frequency distribution of 21 Ne c concentrations in exported sediment is sensitive to the range and spatial distribution of processes operating in the sediment's source areas and that this distribution can be used to infer the range and spatial distribution of erosion rates that characterise the catchment. The results also show that lithology can affect the form of the 21 Ne c concentration distribution indirectly by exerting control on the spatial pattern of denudation in a catchment. Model results further indicate that the form of the distribution of 21 Ne c concentrations in the exported sediment can also be affected by the acquisition of 21 Ne c after detachment from bedrock, in the diffusive (hillslope) and/or advective (fluvial) domains. However, for such post‐detachment nuclide acquisition to be important, this effect needs to at least equal the nuclide acquisition prior to detachment from bedrock. Copyright © 2009 John Wiley and Sons, Ltd.