Sample %³⁹Ar ³⁷Ar/³⁹Ar ³⁶Ar/³⁹Ar ⁴⁰Ar^*/³⁹Ar %⁴⁰Ar^* Age (Ma) SD

DMS87-27 (Sanidine / 20)

1793-03 0.0490 0.00129 4.3313 91.9 11.127 0.138

1793-09 0.0707 0.00962 4.3942 60.8 11.288 0.266

1793-02 0.0351 0.00063 4.4788 96.0 11.504 0.138

1793-01 0.0538 0.00583 4.5054 72.4 11.573 0.267

1793-01B 0.0411 0.01545 4.6069 50.2 11.833 0.288

1793-05 0.0525 0.00032 4.6103 98.0 11.841 0.334

1793-03B 0.0895 -0.00023 4.6292 101.6 11.889 0.615

1793-04 0.0653 0.00054 4.6436 96.7 11.927 0.398

1793-10 0.0873 -0.00002 4.7163 100.2 12.112 0.143

Weighted Mean = 11.59 ± 0.07 SE

1793-07 0.1241 0.00233 5.1453 88.3 13.210 0.197

1793-06 0.0522 0.28648 11.2848 11.8 28.847 1.788

1793-08 0.2024 3.23002 126.3656 11.7 299.358 504.924

Irradiation Data

41B J = 0.005920 ± 0.0000090

61A J = 0.002847 ± 0.0000036

61B J = 0.002783 ± 0.0000024

98A J = 0.000478 ± 0.0000006