Step NÁ 40*Ar/39Ar 36Ar/40Ar x103 39Ar/40Ar x100 37Ar/39Ar x100 %39Ar Cumul. % Atm. Age (Ma) ± (Ma) 1 0.363 3.1396 0.1989 0.000 0.708 92.78 10.8 5.8 2 0.561 1.7785 0.8457 0.000 8.270 52.55 16.7 0.7 3 1.206 0.4816 0.7113 0.000 26.645 14.23 35.6 0.1 4 1.245 0.2983 0.7323 0.000 33.946 8.81 36.8 0.5 5 1.193 0.4353 0.7307 0.000 39.568 12.86 35.2 0.5 6 1.161 0.4983 0.7345 0.000 44.874 14.72 34.3 0.5 7 1.088 0.6317 0.7478 0.000 52.338 18.67 32.2 0.3 8 1.144 0.4347 0.7621 0.000 62.739 12.85 33.8 0.4 9 1.122 0.4880 0.7626 0.000 69.544 14.42 33.2 0.4 10 1.137 0.4265 0.7688 0.000 76.918 12.60 33.6 0.4 11 1.120 0.4545 0.7728 0.000 84.946 13.43 33.1 0.2 12 1.128 0.4478 0.7690 0.000 89.230 13.2 33.4 0.3 13 1.129 0.3836 0.7850 0.000 91.309 11.84 33.4 0.9 14 1.113 0.4987 0.7663 0.000 94.217 14.74 32.9 0.6 15 1.182 0.5545 0.7385 0.000 100.00 16.38 33.5 0.5