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

Joseph A. Graly·Paul R. Bierman·Lucas J. Reusser·Milan J. Pavich
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Abstract

In order to assess current understanding of meteoric 10 Be dynamics and distribution in terrestrial soils, we assembled a database of all published meteoric 10 Be 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 10 Be concentration to other soil characteristics and the comparison of profile depth distributions between geologic settings. Percent clay, 9 Be, and dithionite-citrate extracted Al positively correlate to meteoric 10 Be 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 10 Be distribution with depth. Dithionite-citrate extracted Fe and cation exchange capacity are only weakly correlated to meteoric 10 Be. Percent organic carbon and pH are not significantly related to meteoric 10 Be concentration when all data are complied.The compilation shows that meteoric 10 Be concentration is seldom uniform with depth in a soil profile. In young or rapidly eroding soils, maximum meteoric 10 Be concentrations are typically found in the uppermost 20 cm. In older, more slowly eroding soils, the highest meteoric 10 Be concentrations are found at depth, usually between 50 and 200 cm. We find that the highest measured meteoric 10 Be concentration in a soil profile is an important metric, as both the value and the depth of the maximum meteoric 10Be concentration correlate with the total measured meteoric 10 Be inventory of the soil profile.In order to refine the use of meteoric 10 Be as an estimator of soil erosion rate, we compare near-surface meteoric 10 Be concentrations to total meteoric 10Be soil inventories. These trends are used to calibrate models of meteoric 10 Be 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.

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Joseph A. Graly, Paul R. Bierman, Lucas J. Reusser, Milan J. Pavich. 2010. Meteoric 10 Be in soil profiles - A global meta-analysis. https://doi.org/10.1016/j.gca.2010.08.036

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