10Be - 26Al exposure age calculator


For calculating an exposure age when erosion rate is known independently.

Multiple sample form -- Goehring et al. (2012) Norway calibration data set

Uses nersion 2.2 code. October, 2013.

Written by Greg Balco, balcs@u.washington.edu

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Notes:

Be-10 calibration data from:

Goehring, B., and 6 others, 2012. Late Glacial and Holocene Be-10 production rates for western Norway. Journal of Quaternary Science, v. 27, pp. 89-96.

Calibration data: Excel spreadsheet

Differences between the reference Be-10 production rates inferred from the calibration data in the table below and those reported in the source paper are due to differences in the code used to do the calculation and, to a lesser extent, rounding errors. To ensure consistency between production rate calibration and exposure-age calculations, the values in the table below are calculated using the same code that is used to compute the exposure ages in the online calculator. In this case, the main differences are that i) different optimization schemes are used here and in the source paper, and ii) the source paper included a correction for postglacial isostatic rebound at one of two sites. As the online calculator does not perform an isostatic rebound calculation when computing an exposure age, it is not incorporated in the calibration.

Goehring et al. did not measure Al-26 concentrations. Thus, reference production rates for Al-26 in the table below are calculated from those for Be-10 using (P26 / P10) = 6.75.


Scaling scheme Reference Be-10 Percentage Reduced Reference Al-26
for spallation production rate (atoms/g/yr) uncertainty chi-squared production rate (atoms/g/yr)

St4.07+/-0.163.91.7627.46+/-1.08
De4.19+/-0.173.91.6728.26+/-1.11
Du4.18+/-0.163.91.6928.21+/-1.11
Li4.46+/-0.184.01.6930.09+/-1.19
Lm4.07+/-0.163.91.7627.46+/-1.08


Sample data entry:

Enter data block here.

Note change in Version 2.2:

Production rates and decay constants have been updated in this version to reflect the Be-10 restandardization and half-life revision in Nishiizumi et al., 2007. Thus, you must now specify the standard to which your Be-10 and Al-26 measurements have been normalized. This means that two input fields, the Be-10 and Al-26 standard names, have been added. You'll need to add two columns to your spreadsheets before cutting and pasting data. Refer to the new example spreadsheet here. For a list of currently available standards, see this page.


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