Step NÁ 40*Ar/39Ar 36Ar/40Ar x103 39Ar/40Ar x100 37Ar/39Ar x100 %39Ar Cumul. % Atm. Age (Ma) ± (Ma) 1 0.000 3.6218 1.3930 0.000 0.106 104.93 0.0 0.0 2 3.178 0.6604 0.2640 0.000 0.210 19.90 92.4 7.7 3 2.580 0.0385 0.3848 0.000 2.215 1.56 75.4 0.8 4 1.778 0.0555 0.5553 0.000 4.358 2.09 52.3 0.7 5 1.544 0.0000 0.6514 0.000 22.286 0.29 45.5 0.2 6 1.160 0.0000 0.8603 0.000 28.697 1.08 34.3 0.2 7 1.128 0.0000 0.8812 0.000 33.696 1.42 33.4 0.3 8 1.222 0.0000 0.8096 0.000 37.068 1.93 36.1 0.4 9 1.215 0.0000 0.8174 0.000 41.235 1.59 35.9 0.2 10 1.178 0.0000 0.8450 0.000 46.293 1.34 34.8 0.2 11 1.178 0.0000 0.8461 0.000 51.916 1.21 34.8 0.2 12 1.117 0.0000 0.8934 0.000 58.344 1.12 33.0 0.2 13 1.069 0.0000 0.9326 0.000 64.905 1.14 31.6 0.2 14 1.081 0.0000 0.9173 0.000 69.178 1.73 32.0 0.2 15 1.125 0.0000 0.8842 0.000 74.422 1.36 33.3 0.3 16 1.079 0.0000 0.9095 0.000 77.106 2.72 31.9 0.4 17 1.121 0.0872 0.8720 0.000 79.419 3.03 33.2 0.4 18 1.113 0.0000 0.9032 0.000 100.00 0.35 32.9 0.1