40Ar/39Ar age-spectrum and laser fusion data for volcanic rocks in west central Colorado

Original publisher: [Reston, Va.] : U.S. Dept. of the Interior, U.S. Geological Survey, 2001. OCLC Number: (OCoLC)51796293 Subject: Basalt -- Colorado. Excerpt: ... Table 2. Continued. 39 40 36 % Ar Ar / A r Sample Apparent Age # Steps MSWD Comment and Error ( Ma ) Total Steps K98-8-18E4 9.81 ± 0.19 63.4 5 / 9 0.882 308.0 ± 9.1 Isochron 9.56 1 0 0 9 / 9 295.5 Total gas K98-8-18E5 9.71 ± 0.03 51.2 2 / 9 295.5 Plateau 9.81 ± 0.21 76.8 5 / 9 2.019 303.0 ± 10.3 Isochron 9.63 1 0 0 9 / 9 295.5 Total gas K98-8-18D1 9.95 ± 0.28 4 1 3 / 7 0.054 289.9 ± 6.5 Isochron 9.25 1 0 0 7 / 7 295.5 Total gas K98-8-18C1 10.01 ± 0.15 55.7 3 / 9 0.501 291.4 ± 7.0 Isochron 9.33 1 0 0 9 / 9 295.5 Total gas K98-8-18C2 9.91 ± 0.19 36.2 3 / 8 0.049 292.1 ± 13.9 Isochron 9.34 1 0 0 8 / 8 295.5 Total gas K98-8-18B1 9.96 ± 0.04 89.7 5 / 6 295.5 Plateau 10.35 ± 0.50 1 0 0 6 / 6 0.566 290.1 ± 28.7 Isochron 9.94 1 0 0 6 / 6 295.5 Total gas K98-8-18B2 9.95 ± 0.04 77.8 2 / 6 295.5 Plateau 9.80 ± 0.67 89.7 4 / 6 0.110 410.1 ± 298.3 Isochron 9.96 1 0 0 6 / 6 295.5 Total gas K98-8-18A3 9.41 ± 0.30 1 0 0 8 / 8 3.636 292.3 ± 3.7 Isochron 9.27 1 0 0 8 / 8 295.5 Total gas K98-8-18A4 9.10 ± 0.30 47.8 4 / 6 0.450 301.4 ± 5.8 Isochron 9.16 1 0 0 6 / 6 295.5 Total gas K98-8-17B6 9.97 ± 0.04 75.2 2 / 6 295.5 Plateau 10.09 ± 0.32 94.4 5 / 6 0.157 343.8 ± 116.8 Isochron 10.02 1 0 0 6 / 6 295.5 Total gas K98-8-17A4 10.32 ± 0.13 1 0 0 6 / 6 1.361 270.1 ± 3.1 Isochron 9.36 1 0 0 6 / 6 295.5 Total gas Grand Mesa, Lands End K98-8-18I1 10.42 ± 0.15 7 7 5 / 8 0.075 288.8 ± 13.0 Isochron 10.34 1 0 0 8 / 8 295.5 Total Gas K98-8-18I4 10.35 ± 0.04 73.8 3 / 9 295.5 Plateau 10.33 ± 0.13 92.2 7 / 9 0.311 300.7 ± 6.4 Isochron 10.27 1 0 0 9 / 9 295.5 Total Gas K98-8-18H4 10.76 ± 0.24 36.9 3 / 7 0.673 285.7 ± 5.9 Isochron 9.92 1 0 0 7 / 7 295.5 Total Gas K98-8-18G2 10.72 ± 0.13 1 0 0 8 / 8 3.742 281.8 ± 1.0 Isochron 9.74 1 0 0 8 / 8 295.5 Total Gas K98-8-18G5 9.87 ± 0.08 1 0 0 7 / 7 3.111 270.7 ± 2.1 Isochron 9.15 1 0 0 7 / ...