Meteoric 10Be as a Tracer of Terrestrial Sedimentary Processes

地球宇宙核素应用的发展是当前地球与环境科学中一个新兴的动态领域。在这里，我们建议探索在大气中产生然后沉积到土壤中的陨星10Be。由于其在粘土上的快速吸附，这种核素在沉积过程和长期土壤稳定性中作为速率、年龄和物源的示踪剂具有很大的潜力。前提是对系统进行校准和检查。这种校准现在已经成为可能，也是本建议的目的。它包括：1)对全新世陨坑湖沉积物的大气通量进行定标；2)评价了土壤中10Be的保留行为，其中土壤的年龄是由现场产生的10Be来衡量的；3)通过测量河流沉积物中的10Be浓度来测试进入流域的10Be通量和流出流域的10Be的潜在稳定状态，如果建立了稳定状态，就可以计算全流域的侵蚀速率。该技术的最新应用可能包括量化任何沉积系统的侵蚀速率，即使在无法获得粗粒度石英的情况下，例如从自动流计泵送和采样站采集的沉积物样本用于现代侵蚀速率，以及用于量化古侵蚀速率的湖泊和近海岩心材料。此外，节省样品处理时间和在未来几年安装的加速器质谱仪上测量相对较高的10Be/9Be比率的可能性是整个宇宙核素社区的必要目标。

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.