Meteoric 10Be in soil profiles - A global meta-analysis

In order to assess current understanding of meteoric Be-10 dynamics and distribution in terrestrial soils, we assembled a database of all published meteoric Be-10 soil depth profiles, including 104 profiles from 27 studies in globally diverse locations, collectively containing 679 individual measurements. This allows for the systematic comparison of meteoric Be-10 concentration to other soil characteristics and the comparison of profile depth distributions between geologic settings. Percent clay, Be-9, and dithionite-citrate extracted Al positively correlate to meteoric Be-10 in more than half of the soils where they were measured, but the lack of significant correlation in other soils suggests that no one soil factor controls meteoric Be-10 distribution with depth. Dithionite-citrate extracted Fe and cation exchange capacity are only weakly correlated to meteoric Be-10. Percent organic carbon and pH are not significantly related to meteoric Be-10 concentration when all data are complied. The compilation shows that meteoric Be-10 concentration is seldom uniform with depth in a soil profile. In young or rapidly eroding soils, maximum meteoric Be-10 concentrations are typically found in the uppermost 20 cm. In older, more slowly eroding soils, the highest meteoric Be-10 concentrations are found at depth, usually between 50 and 200 cm. We find that the highest measured meteoric Be-10 concentration in a soil profile is an important metric, as both the value and the depth of the maximum meteoric The concentration correlate with the total measured meteoric Be-10 inventory of the soil profile. In order to refine the use of meteoric Be-10 as an estimator of soil erosion rate, we compare near-surface meteoric Be-10 concentrations to total meteoric Be-10 soil inventories. These trends are used to calibrate models of meteoric Be-10 loss by soil erosion. Erosion rates calculated using this method vary based on the assumed depth and timing of erosional events and on the reference data selected. (C) 2010 Elsevier Ltd. All rights reserved.