Meteoric 10Be as a Tracer of Terrestrial Sedimentary Processes

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The development of terrestrial cosmogenic nuclide applications is currently a dynamic field emerging in the Earth- and Environmental Sciences. Here we propose to explore meteoric 10Be that is produced in the atmosphere and then is deposited into soil. Due to its rapid adsorption onto clays, this nuclide has great potential as a tracer of rates, ages, and provenance in sedimentary processes and long-term soil stability. Prerequisite is calibrating and checking the system. Such a calibration has now become possible and is the aim of this proposal. It includes 1) a calibration of the meteoric flux over the Holocene from well-dated crater lake sediments; 2) an assessment of 10Be retention behavior in soils of which the age is measured by in situ-produced 10Be; 3) a test of potential steady state between 10Be flux into and 10Be export out of a river basin by measuring the 10Be concentration in river sediment which, if steady state is established, would allow for calculation of basin-wide erosion rates. Newly possible applications for this technique include quantifying erosion rates from any sedimentary system even where coarse-grained quartz is unavailable such as sediment sampled from automated stream gauge pumping and sampling stations for modern erosion rates, and lake and offshore core material for quantifying paleoerosion rates. In addition, the savings in sample processing time and the possibility of measuring relatively high 10Be/9Be ratios on the accelerator mass spectrometers to be installed in the coming years are necessary goals for the entire cosmogenic nuclide community.