Tracing Hillslope Sediment Production and Transport with in situ and Meteoric 10Be

Jungers, Matthew; Bierman, Paul; Matmon, Ari; Nichols, Kyle; Larsen, Jennifer; Finkel, Robert

lina,oiltr upon amto iriability in 10Be conc themplepe diffusively untilnnel net situ-prrofiles, indicates that over millennial timescalil-saprolite bouepth and are correlated to concus explained by similar Al and Ben situ-produced 10Be increase dohe data suggest virtual downslopsport layer 60 cm thick. The ths on the rooting depth and consehich reflect depth to the soil/sst that soil production is balan the meteoric 10Be inventories. Major element geochemical analysABSTRACT: We use in situ-produced and meteoric 10Be, analyzed in soils from 28 pits on four hillcrest-parallel transects along a 14 hilslope in the Great Smoky Mountans, North Caroli as tracers of s production and ansport. We relyalgamation both nvestigate and smooth spatial vaentrations. Lidar indicates that hillslope is topographically cox and that soil is moved downslo it encounters the ephemeral chawork and is rapidly exported. Inoduced 10Be, measured in depth pes, soils are mixed above the sondary. In contrast, meteoric 10Be concentrations increase with drrent increases of dithionite-extractable Al and pH, observation mobility in the soil. The concentrations of both meteoric and iwnslope proportional to the maximum soil particle path length. Te soil velocities of 1.1–1.7 cm yr1 in a well-mixed active tranickness of this transport layer is constant downslope and dependquent root wad thickness of downed trees on the slope, both of waprolite boundary. Both meteoric and in situ-produced 10Be suggeced by surface denudation at rates between 10 and 13 m Myr1. Soil residence times on the slope range from 21 to 33 kyr based onis suggests little if any elemental loss during soil transport downslope.