Finding the Dates

After doing all of this:
  1. Skeleton plotting the core
  2. Showing the master chronology
  3. Matching the pattern of your skeleton plot with the master
Now determine the actual dates of the virtual sample and consider possible paleoenvironmental applications

How to find the start and end dates:
  • For example, the virtual sample has 21 rings
  • The skeleton plot extends from line #0 to line #20, as on the right
  • The pattern matching with the master chronology is obvious
  • Therefore:
    • The first ring (line #0 on the skeleton plot) corresponds to 1809
    • The last ring (line #20 on the skeleton plot) corresponds to 1829
    • Year dates of formation of all 21 rings are now known
  • Congratulations: This sample is crossdated by skeleton plotting
finding start and end dates

show or hide answers When you try skeleton plotting for yourself, you can check your answers:
  • There will be a button to "Show or Hide Answers," as on the left
  • When you mouse click to show answers, a box of answers will appear, as on the right
  • If the sample had ring-growth anomalies, then the answer will include dates of absent/false rings as well
start and end dates



Paul R. Sheppard
Laboratory of Tree-Ring Research, The University of Arizona
Tucson, Arizona 85721 USA
office: (520) 621-6474, fax: (520) 621-8229
Comments to: sheppard@ltrr.arizona.edu