A radiometric age for the Cretaceous-Tertiary boundary based upon K-Ar, Rb-Sr, and U-Pb ages of bentonites from Alberta, Saskatchewan, and Montana
A radiometric age for the Cretaceous-Tertiary boundary based upon K-Ar, Rb-Sr, and U-Pb ages of bentonites from Alberta, Saskatchewan, and Montana
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基于阿尔伯塔省、萨斯喀彻温省和蒙大拿州膨润土的 K-Ar、Rb-Sr 和 U-Pb 年龄的白垩纪-第三纪边界的辐射年龄
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发表时间：
1988
期刊：
影响因子：
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通讯作者：
I. Mcdougall
中科院分区：
文献类型：
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作者：
H. Baadsgaard;J. F. Lerbekmo;I. Mcdougall
对阿尔伯塔省红鹿谷、法国萨斯喀彻温省红鹿谷和蒙大拿州地狱溪附近北美白垩纪-第三纪(K-T)界线的膨润土进行了K-Ar、Rb-Sr和U-Pb测年。根据孢粉地层对比和存在明显的Ir异常，三个采样的膨润土层都出现在已建立的K-T边界之上不到1 m的位置。有证据表明，可能存在系统误差，给出的测年结果超出名义统计误差值。尽管可能存在恒定误差，但九个平均日期的加权平均值计算为64.3mA± 1.2mA(2 标准差)。未加权平均得到的宏观平均年龄为64.4 ± 1.2 Ma。
Bentonites associated with coal seams at the North American Cretaceous–Tertiary (K–T) boundary in the Red Deer Valley of Alberta, in the Frenchman Valley of Saskatchewan, and near Hell Creek, Montana, were dated by the K–Ar, Rb–Sr, and U–Pb methods. Based upon palynological stratigraphic correlation and the presence of a sharp iridium anomaly, the three sampled bentonite horizons all occur less than 1 m above the established K–T boundary. There is evidence of possible systematic errors giving dating results outside nominal statistical error values. Despite possible constant errors, the weighted mean of nine average dates is calculated as 64.3 ± 1.2 Ma (2σ standard deviation). An unweighted averaging produces a grand mean age of 64.4 ± 1.2 Ma.