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

DME91-41 (Sanidine / 98A)

7174-02 0.0213 0.00145 15.8278 97.4 13.589 0.197

7174-07 0.0582 0.00040 15.9122 99.3 13.661 0.147

7174-08 0.0000 0.00126 15.8924 97.7 13.644 0.095

7174-09 0.0000 0.00146 15.9245 97.4 13.672 0.187

7174-10 0.0000 0.00052 15.9054 99.0 13.655 0.119

Weighted Mean = 13.65 ± 0.06 SE

DME91-41 (Glass / 98A)

7185-01A 14.5 0.1593 0.00498 17.4518 92.3 14.978 0.302

7185-01B 1.0 0.6002 0.00247 16.9513 96.1 14.550 0.243

7185-01C 0.5 0.4866 0.00540 16.5883 91.4 14.240 0.417

7185-01D 1.3 0.1247 0.00141 16.9101 97.6 14.515 0.175

7185-01E 9.6 0.1654 0.00166 17.3040 97.3 14.851 0.061

7185-01F 15.9 0.1388 0.00185 17.2699 97.0 14.822 0.072

7185-01G 9.5 0.1292 0.00155 17.1905 97.5 14.754 0.065

7185-01H 6.4 0.1485 0.02264 17.1369 72.0 14.709 0.090

7185-01I 18.2 0.0829 0.04104 17.1700 58.6 14.737 0.093

7185-01J 8.3 0.0841 0.00216 17.1869 96.5 14.751 0.057

7185-01K 15.1 0.1364 0.00365 17.1088 94.1 14.685 0.055

Plateau Age = 14.75 ± 0.03 SE

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