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1286257 
Journal Article 
Climate-driven processes of hillslope weathering 
Dixon, JL; Heimsath, AM; Kaste, J; Amundson, R 
2009 
Yes 
Geology
ISSN: 0091-7613 
Geological Society of America (GSA) 
United States (USA) 
37 
11 (November 2009) 
975-978 
Climate controls erosion and weathering on soil-mantled landscapes through diverse processes that have remained difficult to disentangle due to their complex interactions. We quantify denudation, soil and saprolite weathering, and soil transport near the base and crest of the western slope of the Sierra Nevada to examine how large differences in climate affect these processes. Depth profiles of fallout radionuclides and field observations show relative differences in erosion and weathering processes at these two climatically diverse sites, and our data suggest fundamentally different patterns of soil production and transport mechanisms: biotically driven soil transport at low elevation, and surface erosion driven by overland flow at high elevation. Soil production rates from cosmogenic (super 10) Be decrease from 31.3 to 13.6 m/Ma with increasing soil depth at low elevation, but show uncertain depth dependence at the high elevation site. Our data also show a positive correlation between physical erosion and saprolite weathering at both sites. Highly weathered saprolites are overlain by weakly weathered and rapidly eroding soils, while chemically less depleted saprolites are overlain by slowly eroding, more weathered soils. Our data are among the first to quantify the critical role of saprolite weathering in the evolution of actively eroding upland landscapes, and our results provide quantitative constraints on how different climates can shape hillslopes by driving processes of erosion and weathering. 
Sierra Nevada; metals; United States; soils; quantitative analysis; field studies; landform evolution; Fresno County California; weathering; soil erosion; slopes; erosion; beryllium; climatic controls; isotopes; geomorphology; California; alkaline earth metals; denudation; geochronology; Be-10; saprolite; relative age; runoff; radioactive isotopes