187Re-187Os Calibration of Molybdenite from Henderson, Colorado: A New NIST Reference Material

[11 . 1876]基于铼（Re）向锇（Os）衰变的地球计时器的应用正在迅速扩大，而且没有经过国家标准与技术研究所（NIST）认证的参考材料用于实验室间的比较。化学和质谱方法的进步使得即使在低ppt水平的样品上也能高精度地测定Re和Os。辉钼矿（MoS2）特别适合于Re-Os计时器，因为它通常含有高浓度的母Re，而基本上没有初始的子Os。因此，即使在非常年轻的样品中，187Re到187o的衰变也可以得到精确的年龄，而无需对初始o进行校正。随着Re-Os测年需求的增加，特别是辉钼矿的Re-Os测年，需要一种可接受的实验室间比较参考材料变得至关重要。我们建议校准Re-Os辉钼矿标准物质，与阿尔伯塔大学和NIST合作。提议的Re-Os参考辉钼矿来自科罗拉多州亨德森，那里有一个经过充分研究的钼矿床。NIST将对亨德森辉钼矿粉进行物理混合、拆分和装瓶。具有统计代表性的样品集将由科罗拉多州立大学的airy实验室和阿尔伯塔大学的同位素实验室进行分析。标准物质的分配将完全由NIST处理，辉钼矿标准物质的成本将仅反映NIST为其部分工作所产生的成本。＊＊＊

0111876SteinUse of the geochronometer based on the decay of rhenium (Re) to osmium (Os) is rapidly expanding, and there are no reference materials certified by the National Institute of Standards and Technology (NIST) for inter-laboratory comparison. Advances in chemical and mass spectrometric procedures permit high precision determination of Re and Os, even on low-ppt level samples. Molybdenite (MoS2) is uniquely suited for the Re-Os chronometer because it commonly contains high concentrations of the parent Re and essentially no initial daughter Os. Thus, the decay of 187Re to 187Os yields precise ages, even in very young samples, without correction for initial Os. With increasing demand for Re-Os dating, particularly of molybdenite, the need for an accepted reference material for inter-laboratory comparison has become crucial. We propose to calibrate a Re-Os molybdenite reference material, working together with University of Alberta and NIST. The proposed Re-Os reference molybdenite is from Henderson, Colorado, the location of a well-studied molybdenum deposit. NIST will physically mix, split, and bottle the Henderson molybdenite powder. Statistically representative sets of samples will be analyzed by the AIRIE Lab at Colorado State University and by the isotope lab at the University of Alberta. The distribution of the reference material will be fully handled by NIST, and the cost for the molybdenite reference material will reflect only the costs incurred by NIST for their part of the work. ***