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Meteoric Beryllium‐10 as a Tracer of Erosion Due to Postsettlement Land Use in West‐Central Minnesota, USA
Author(s) -
Jelinski Nicolas A.,
Campforts Benjamin,
Willenbring Jane K.,
Schumacher Thomas E.,
Li Sheng,
Lobb David A.,
Papiernik Sharon K.,
Yoo Kyungsoo
Publication year - 2019
Publication title -
journal of geophysical research: earth surface
Language(s) - English
Resource type - Journals
eISSN - 2169-9011
pISSN - 2169-9003
DOI - 10.1029/2018jf004720
Subject(s) - erosion , magnitude (astronomy) , hydrology (agriculture) , geology , environmental science , tracer , soil science , physical geography , geomorphology , geography , geotechnical engineering , astronomy , nuclear physics , physics
Meteoric beryllium‐10 ( 10 Be m , t 1/2 = 1.4 Myr) is a cosmogenic radionuclide that remains largely underutilized for deriving hillslope‐scale estimates of erosion on uplands under conditions of land use change. We applied two different models for estimating erosion rates from observed 10 Be m concentrations (a one‐dimensional model predicting vertical profiles of 10 Be m within hillslope soils [loss only, diffusion only, LODO] and a two‐dimensional model predicting the concurrent evolution of hillslope topography and 10 Be m distributions via bioturbation, chemical mobility, and surface erosion [Be2D]). Both models were used to derive pre‐European and post‐European settlement erosion rates ( E nat and E post , respectively) across paired cultivated and uncultivated hillslopes in west‐central Minnesota, USA. E post estimates from 10 Be m were compared to E post estimates derived from 137 Cs inventories and the process‐based Water and Tillage Erosion Model (WaTEM). The results from these models suggest that erosion rates from upper positions on the cultivated hillslope have increased from an average of 0.047 mm/year under natural conditions to E post values of 3.09 mm/year. The Be2D and LODO models, on average, produced E post estimates that were similar in magnitude to WaTEM and 137 Cs conversion models. This numerical convergence does not imply absolute 10 Be m model accuracy, particularly when considering the uncertainties inherent in each approach, but it does suggest that the orders of magnitude increase in estimated erosion rates from E nat to E post is robust. Additionally, the pattern of E post estimates produced using 10 Be m conversion models is supported by the distribution of soil inorganic carbon at the study site. Our results demonstrate that 10 Be m can provide reasonable estimates of both predisturbance and postdisturbance erosion rates in landscapes that have undergone extensive human modification.