3. Skeleton plotting

Objectives:

• Students will understand the concept of skeleton plotting / crossdating

Discussion:

• Describe skeleton plotting (be sure to include scale of 1 to 10 of marks)
• Why skeleton plot? Study ecology, climatology, geology, anthropology - To put the present in perspective of the past, To better understand current environmental processes and conditions, and To improve the understanding of possible environmental issues of the future
• Why does it work if it is ALL relative?
• Examples
• Difference between a skeleton plot and a master chronology

Homework:

Website:

http://tree.ltrr.arizona.edu/skeletonplot/introcrossdate.htm

1. Click on AND READ links 1 through 12
2. Click on 'Try skeleton plotting yourself' (The image should look like figure 1 below).
3. CONCENTRATE only on the narrow rings!!
4. You can change the zoom on the core and the graph by clicking on 1x, 2x, or 3x for the core and large, medium, small for the graph paper. This may help you see tiny rings.
5. If you put a mark on the wrong graph line or want to change the height of the mark, click on 'ERASE' and click on that mark. Be sure to click on 'DRAW' to continue.
6. Click on the line that corresponds to the ring number at the height value you want to give it. (For example, the ring you are looking at is narrow, but not really narrow with respect to the rings on either side. So the ring you are looking at should get a 3 on the 1 to 10 scale. Click on the 3^rd line up from the bottom of the graph paper.)
7. Move the core by clicking and dragging to the left. (See figure 2 for example of completed skeleton plot.)
8. Click on the MASTER button when you have finished plotting the rings on the core. (It should be 60.)
9. To find the match - Click and drag the master until you find the match. (See figure 3 for example of a match.)
10. If you accidently click on the master and make a line, click on 'REDO MARKS ON MASTER'
11. When you think you have a match, click on 'ANSWER' to confirm your match. (See figure 4 for example of answer. Note how the graph years match the answer box years.)
12. When you succeed, hold down the Alt and Print Screen buttons to copy your match
13. Use your favorite word processing software and click on Edit then click on Paste Special
14. Write a summary (half page, double spaced, 12 font, 1 inch margins) of what you learned about crossdating and skeleton plotting. Include definitions, applications, difference between complacency and sensitivity, etc.

Figure 1.

Figure 2.

Figure 3.

Figure 4.