
Notes:
Be10 calibration data from:
Heyman, J., 2014. Paleoglaciation of the Tibetan Plateau and surrounding mountains based on exposure ages and ELA depression estimates.
Reference production rates and fit values are computed using this page and this calibration data set excerpted from the supplemental data table in the paper. This differs from the calculations in the paper in that all samples are weighted equally according to their uncertainties, rather than all sites being weighted equally. However, this method ensures that exactly the same code is used for both production rate and exposure age calculations. Note, however, that the results of both methods are indistinguishable.
Heyman did not compile Al26 concentrations. Thus, reference production rates for Al26 in the table below are calculated from those for Be10 using (P26 / P10) = 6.75.

Trace information from calibration code:
Calibration data set name: Heyman 2014
Computation time: 258.17 sec
Calibration wrapper version: 2.2caldev
Objective function version: 2.2dev
Age calculation version: 2.1
Muon calculation version: 1.1
Constants version: 2.2.1


Scaling scheme 
Reference Be10 
Percentage 
Reduced 
Reference Al26 
for spallation 
production rate (atoms/g/yr) 
uncertainty 
chisquared 
production rate (atoms/g/yr) 

St  3.92  +/  0.14  3.7  1.77  26.46  +/  0.97  De  3.82  +/  0.14  3.6  11.04  25.74  +/  0.93  Du  3.84  +/  0.14  3.6  9.79  25.89  +/  0.94  Li  4.12  +/  0.15  3.6  8.60  27.82  +/  1.01  Lm  3.86  +/  0.14  3.7  2.13  26.07  +/  0.95 

Scaling scheme fits to calibration data: This plot shows the fit
between each scaling scheme and the calibration data. The filled circles are calculated
reduced chisquared values for evenly spaced trial values of the reference Be10 production rate. The corresponding
lines are the polynomial interpolations used to determine the value that minimizes the fit parameter.
Colors: black, St; red, De; green, Du; blue, Li; cyan, Lm. If the lines don't go through the corresponding
colored data points, or if they don't look more or less parabolic, there is
likely a problem with the fit algorithm.


Same thing, different presentation:This plot shows ratios of exposure ages for
the calibration calculated using the bestfitting reference production rate (t) to the actual
independently determined ages of the sites (truet). Color coding for scaling schemes as above.
The gray band represents the 1stderr uncertainty in the bestfitting reference production
rate. There is no particular significance to elevation as the independent variable other than
that it usually spreads out the data nicely.



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 Be10 restandardization and halflife revision
in Nishiizumi et al., 2007. Thus, you must now specify the standard to
which your Be10 and Al26 measurements have been normalized. This means
that two input fields, the Be10 and Al26 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.




This website is supported by the
National Science Foundation
via the CRONUSEarth project

