10Be - 26Al exposure age calculator

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

Multiple sample form. Version 2. January, 2007.


Written by Greg Balco, balcs@u.washington.edu
Calculators home
Erosion rates

Use a test sample
for demonstration
purposes --

Enter data block here.See below for formatting instructions.

Note change in Version 2:
This form now serves as the entry form for single or multiple samples. However, the result pages differ: entering only a single sample yields additional plots showing i) production rate changes predicted by the time-dependent scaling schemes, and ii) a comparison of ages generated by the various scaling schemes.
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It takes a few seconds to calculate each exposure age. If the timeout setting on your browser is too short, it will stop waiting for the page before the calculations are done. You can set the wait time to a longer value on some browsers. If that's not true of yours (Safari, for example), you will have to submit fewer samples at once.
Formatting instructions:
This form is designed to have text pasted into it from a text editor or an Excel spreadsheet. The formatting requirements are somewhat finicky, but easy to use once you have a spreadsheet set up appropriately. An example spreadsheet is here. The rules are as follows:
  1. Enter plain ASCII text only.
  2. Each sample should occupy its own line.
  3. Each line should have thirteen elements, as described below.
  4. Elements should be separated from each other by white space (spaces or tabs).
  5. Something other than white space must be entered for each element. For example, if you have no Al measurements for a sample, you must enter "0" in the Al concentration and Al uncertainty positions.
In most cases, pasting directly from an Excel spreadsheet should satisfy the rules. An example of an acceptable input text block appears below.

The thirteen elements are as follows:

  1. Sample name. Any text string not exceeding 24 characters. Sample names may not contain white space or any characters that could be interpreted as delimiters or escape characters, e.g., slashes of both directions, commas, quotes, colons, etc. Stick to letters, numbers, and dashes.
  2. Latitude. Decimal degrees. North latitudes are positive. South latitudes are negative.
  3. Longitude. Decimal degrees. East longitudes are positive. West longitudes are negative.
  4. Elevation/pressure. Meters or hPa, respectively, depending on selection below.
  5. Elevation/pressure flag. Specifies how to treat the elevation/pressure value. This is a three-letter text string. If you have supplied elevations in meters and the standard atmosphere is applicable at your site (locations outside Antarctica), enter "std" here. If you have supplied elevations in meters and your site is in Antarctica, enter "ant" here. If you have entered pressure in hPa, enter "pre" here. Any text other than these three options will be rejected.
  6. Sample thickness. Centimeters.
  7. Sample density. g cm-3.
  8. Shielding correction. Samples with no topographic shielding, enter 1. For shielded sites, enter a number between 0 and 1.
  9. Erosion rate inferred from independent evidence. cm yr-1.
  10. 10Be concentration. Atoms g-1. Standard or scientific notation.
  11. Uncertainty in 10Be concentration. Atoms g-1. Standard or scientific notation.
  12. 26Al concentration. Atoms g-1. Standard or scientific notation.
  13. Uncertainty in 26Al concentration. Atoms g-1. Standard or scientific notation.
Note: Nuclide concentrations should already take account of carrier and process blanks. Also, all measurements should be normalized to the Nishiizumi Al-26 and Be-10 standards (fully referenced in the documentation). For measurements made at LLNL, this is true already; it may require adjusting measurements made at other AMS labs. PRIME Lab users in particular should take note of this.. There is additional discussion of these issues in the documentation.

Here is an example of an acceptable input text block. You can paste this in above to try a sample calculation.
     PH-1 41.3567 -70.7348 91 std 4.5 2.7 1 8e-5 123500 3700 712400 31200
     01-MBL-059-BBD -77.073 -145.686 712 ant 4.75 2.65 0.997 0 353000 8000 1940000 49000
     NH-1 57.968 -6.812 790 std 3 2.65 1 0 943000 28000 0 0
Here is an Excel spreadsheet containing example data that you can paste in above to try a sample calculation.

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