10Be - 26Al exposure age calculator

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

Multiple sample form -- Blard et al. (2013) tropical Andes calibration data set

Uses version 2.2 code. September, 2014.

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

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Geological calibration data from:

Blard, P.-H., Braucher, R., Lave, J., Bourles, D., 2013. Cosmogenic Be-10 production rate calibrated against He-3 in the high tropical Andes (3800-4900 m, 20-22 S). Earth and Planetary Science Letters, v. 382, pp. 140-149.

Blard, P.-H., Lave, J., Sylvestre, F., Placzec, C.J., Claude, C., Galy, V., Condom, T., Tibari, B., 2013. Cosmogenic He-3 production rate in the high tropical Andes (3800 m, 20 S): implications for the local last glacial maximum. Earth and Planetary Science Letters, v. 377-78, p. 260-275.

The reference production rates listed here differ from those published in the source paper due to differences in the code used to do the calculation. 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. For details, see the explanantion here.

Reference production rates are only calculated here for the "St" and "Lm" scaling schemes. For discussion of this issue, also see here. Thus, results of exposure age calculations will not include results for other scaling schemes. In addition, results pages may contain warnings that samples are "saturated with respect to" other scaling schemes; these are spurious and should be ignored.

Blard et al. did not report 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)


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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