Table 3. 40Ar/39Ar Dating of feldspars in Leg 165 tephra layer.
Core,
section, interval (cm)
|
Analysis
number |
40Ar/39Ar
|
38Ar/39Ar
|
37Ar/39Ar
|
36Ar/39Ar
|
39Ar
|
40Ar*
(%) |
40Ar*/39Ar
|
Age
(Ma) |
±
(m.y.)
|
wi
|
xi*wi
|
Mean (Ma)
|
Error (Ma)
|
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
165-999A- | ||||||||||||||
48X-6, 43 | 1 | 1.80 | 0.013 | 1.62 | 0.0010 | 16.3 | 84.36 | 1.516 | 16.21 | 3.17 | 0.10 | 1.62 | ||
48X-6, 43 | 2 | 1.77 | 0.012 | 1.43 | 0.0016 | 20.2 | 73.72 | 1.302 | 13.93 | 2.56 | 0.15 | 2.12 | ||
48X-6, 43 | 3 | 1.69 | 0.012 | 0.59 | 0.0006 | 23.3 | 89.06 | 1.504 | 16.08 | 2.22 | 0.20 | 3.27 | ||
48X-6, 43 | 4 | 2.11 | 0.013 | 0.77 | 0.0009 | 36.4 | 87.75 | 1.854 | 19.79 | 1.42 | 0.49 | 9.79 | ||
48X-6, 43 | 5 | 1.75 | 0.013 | 0.96 | 0.0000 | 38.0 | 99.85 | 1.743 | 18.62 | 1.36 | 0.54 | 10.07 | ||
48X-6, 43 | 6 | 1.69 | 0.012 | 0.81 | 0.0000 | 33.9 | 100.00 | 1.693 | 18.08 | 1.53 | 0.43 | 7.77 | ||
48X-6, 43 | 7 | 1.82 | 0.014 | 1.09 | 0.0013 | 32.6 | 78.82 | 1.436 | 15.35 | 1.59 | 0.40 | 6.10 | ||
48X-6, 43 | 8 | 1.81 | 0.012 | 1.73 | 0.0013 | 32.7 | 79.26 | 1.431 | 15.30 | 1.58 | 0.40 | 6.10 | ||
48X-6, 43 | 9 | 1.83 | 0.010 | 1.84 | 0.0016 | 22.8 | 74.08 | 1.359 | 14.53 | 2.26 | 0.20 | 2.83 | ||
48X-6, 43 | 10 | 1.88 | 0.014 | 0.71 | 0.0008 | 39.5 | 87.42 | 1.644 | 17.57 | 1.10 | 0.83 | 14.60 | ||
48X-6, 43 | 11 | 2.00 | 0.017 | 0.05 | 0.0024 | 12.9 | 65.23 | 1.304 | 13.94 | 3.36 | 0.09 | 1.23 | ||
48X-6, 43 | 12 | 2.08 | 0.017 | 0.43 | 0.0012 | 23.4 | 83.12 | 1.730 | 18.47 | 1.85 | 0.29 | 5.42 | ||
48X-6, 43 | 13 | 2.31 | 0.014 | 0.57 | 0.0033 | 40.2 | 57.48 | 1.329 | 14.21 | 1.08 | 0.86 | 12.16 | ||
48X-6, 43 | 14 | 1.96 | 0.015 | 0.27 | 0.0014 | 81.8 | 78.37 | 1.535 | 16.40 | 0.54 | 3.47 | 56.96 | ||
48X-6, 43 | 15 | 1.91 | 0.021 | 0.38 | 0.0014 | 31.5 | 78.30 | 1.497 | 16.00 | 1.38 | 0.53 | 8.46 | ||
48X-6, 43 | 16 | 2.15 | 0.015 | 0.28 | 0.0024 | 52.4 | 66.58 | 1.432 | 15.30 | 0.83 | 1.45 | 22.26 | ||
16.36 |
0.31
|
Notes: %Atm = 100*[(40Ar/39Ar-295.5*36Ar/39Ar)40Ar/Ar]. 40Ar*/39Ar = the ratio of the radiogenic isotope of argon (40Ar) to the 39Ar produced in the reactor from potassium. wi = the weighting used in the weighted mean and is the inverse of variance on each measurement. xi*wi = the weighting multiplied by the measured age of each measurement.