In the next 3 stages, Larry will separate the basalt from the chert hammer debris in the different screens. The screens are; 1/2 inch, 1/4 inch, and window screen (w/s).
STAGE 3
3hours-24minutes-22seconds long
Total time at the end of stage 3 = 5hrs-38min-22
(from 2hrs-14min to 5hrs-38min-22secs)
Total debitage recovered in this stage: 686.1g
Screen size Material % found in this stage Grams Grams per minute (GPM)
1/2"
basalt
2%
13.8g
0.65GPM
1/2"
chert
9.4%
64.6g
0.32GPM
1/4" basalt
5.4%
37.1g
0.18GPM
1/4" chert
3.6%
25.1g 0.12GPM
w/s
basalt
12%
82.8g 0.40GPM
w/s chert
8.9%
61.6g 0.30GPM
Fines (too small)
chert/basalt combination
59.3%
407.4g 1.99GPM
Note that the fines have nearly doubled from the previous stage from 29.6% to 59.3%. Using a 1/4" screen in this stage, we would recover 50.9g (18.8+37.1) or 6.4% of the general evidence. In window screen we'd recover 133.7g or 18.4% of the general evidence.
Adding the recovered basalt from all 3 screens, we get a total of133.7g.
Adding the 1/2 and 1/4 screens, we get a total of 38.9g.
Divide 38.9 by 133.7 and we get 29% basalt recovery in 1/4" screen.
Adding the recovered chert from all 3 screens, we get a total of 151.3g.
Adding the chert for the 1/2" and 1/4", we get a total of 89.7g.
Divide 89.7 by 151.3 and we get 59.2% chert recovery in the 1/4" screen.
Basalt debitage is produced at 0.65 grams per minute.
Chert debitage is produced at 0.74 grams per minute.
