Table
1. 40Ar/39Ar results from Internal Standard
(Tmr3: INF-94-531 anorthoclase) from Santa Isabel Wash
|
Sample
|
J-Factor
|
# of aliquots
included in calculation over total #
|
Inverse
Isochron
Age (Ma)
(± 2s
SD)
|
40Ar/39Ar
(± 1s
SD)
|
40Ar/36Ar
(± 1s
SD)
|
MSWD
|
95% critical
MSWD range
(after Mahon [1996])
|
|
MIT
|
|
|
|
|
|
|
|
|
INF-94-532,3
|
0.003480
|
10
|
6.4 ± 0.2
|
1.02± 0.02
|
294 ± 6
|
1.71
|
0.27-2.19
|
|
UCLA
|
|
|
|
|
|
|
|
|
UofM#75 (tube
1)
|
|
|
|
|
|
|
|
|
INF-94-53A
|
0.0004178
|
6/6
|
6.3 ± 0.3
|
8.37 ±
0.07
|
293 ± 2
|
4.80
|
0.12-2.78
|
|
INF-94-53B
|
0.0004215
|
5/5
|
6.2 ± 0.3
|
8.23 ±
0.06
|
291 ± 1
|
1.00
|
0.07-3.12
|
|
INF-94-53C
|
0.0004174
|
5/5
|
6.2 ± 0.3
|
8.29 ±
0.06
|
292 ± 3
|
3.19
|
0.07-3.12
|
|
INF-94-53g 3
|
0.0004191
|
4/4
|
6.2 ± 0.3
|
8.22 ±
0.07
|
292 ± 2
|
1.12
|
0.03-3.69
|
|
UofM#81 (tube
1)
|
|
|
|
|
|
|
|
|
INF-94-53A3
|
0.0008170
|
4/6
|
6.4 ± 0.6
|
4.38 ±
0.18
|
287 ± 4
|
1.29
|
0.03-3.69
|
|
INF-94-53B3
|
0.0008275
|
5/5
|
6.7 ± 0.4
|
4.50 ±
0.11
|
283 ± 5
|
2.27
|
0.07-3.12
|
|
INF-94-53C3
|
0.0008059
|
5/5
|
6.5 ± 0.3
|
4.50 ±
0.05
|
287 ± 2
|
0.33
|
0.07-3.12
|
|
(tube 2)
|
|
|
|
|
|
|
|
|
INF-94-53D3
|
0.0008066
|
4/4
|
6.5 ± 0.3
|
4.48 ±
0.07
|
287 ± 2
|
0.73
|
0.03-3.69
|
|
INF-94-53E3
|
0.0008097
|
5/5
|
6.4 ± 0.3
|
4.37 ±
0.05
|
289 ± 2
|
0.18
|
0.07-3.12
|
|
INF-94-53F3
|
0.0007928
|
2/2
|
6.4 ± 0.3
|
4.50 ±
0.05
|
288 ± 2
|
N/A
|
N/A
|
|
|
|
# of duplicate
splits included
in calculation over total #
|
Weighted Mean
Age (Ma)
(± 2s
SD)
|
|
|
MSWD
|
95% critical
MSWD range (after
Mahon [1996])
|
|
UofM#75
|
|
4/4
|
6.24 ±
0.08
|
|
|
0.56
|
0.03-3.69
|
|
UofM#81
|
|
6/6
|
6.46 ±
0.24
|
|
|
1.02
|
0.12-2.78
|
|
Overall
|
|
10/10
|
6.31 ±
0.32
|
|
|
3.50
|
0.27-2.19
|
1 UTM coordinates
of Sample Location (north, east): 3362905mN
0701401mE
2 MIT Results
recalculated for consistency using Fish Canyon sanidine age of 27.8 and
isochron regression routines of Mahon (1996)
3 Sample
irradiated with g radiation