K/Ar Calibration of MMhb - 2

MMhb 的 K/Ar 校准 - 2

• 批准号: 9405620
• 负责人: Michael Kunk
• 金额: --
• 依托单位: UNITED STATES DEPT OF GEOLOGICAL SURVEY
• 依托单位国家: 美国
• 项目类别: Interagency Agreement
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-15 至 1996-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9405620&HistoricalAwards=false
• 关键词: Ar; Calibration; MMhb

9405620 Kunk One of the most widely used techniques for measuring radiometric ages of rocks and minerals is the so-called 40Ar/39Ar or argon-argon method, a variation of the potassium-argon or K/Ar method. Both methods make use of the known decay rate of natural 40K to 40Ar and the retention of the daughter product argon inside the mineral grain. The argon-argon method is further dependent on irradiation of the unknown sample in a nuclear reactor in order to convert some 39K to 39Ar by an n, p nuclear reaction. A calibration standard of known age is irradiated at the same time as the sample. The precision of all ages reported by this method are determined by the precision with which the standard is known. This award will provide partial funding to allow personnel of the National Institute of Standards and Technology (NIST) and the U.S. Geological Survey to bring state-of-the-art methods to bear on producing the most reliable mineral standard possible for interlaboratory calibrations of argon-argon dating. The standard will be made available to the geochronology research community through distribution by the Standard Reference Materials Program of NIST. *** 9406684 Johnson This award provides partial funding for the support of a technician assigned to the Radiogenic Isotope Laboratory in the Department of Geology and Geophysics at the University of Wisconsin, Madison. The technician will assist in the operation and maintenance of the laboratory's equipment that includes a multicollector thermal ionization mass spectrometer and associated instrumentation for sample preparation and data analysis. The laboratory is a resource for mass spectrometric analysis needed in research and teaching projects in the earth sciences by a large number of researchers on-campus and off-campus. Research applications include work on Arctic Ocean sediments, mantle geochemistry, volcanism, geochronology of carbonates in the Michigan Basin and Wisconsin Arch provinces, and Archean and Proterozoic granites. The technician will also participate in the technical developmental work of the laboratory, including the development of new methods for the quantitative measurement of the isotopes of hafnium. ***

9405620 Kunk测量岩石和矿物放射性年龄最广泛使用的技术之一是所谓的40 Ar/39 Ar或氩-氩法，这是钾-氩或K/Ar法的一种变体。这两种方法都利用了天然40 K到40 Ar的已知衰变速率和在矿物颗粒内部保留子产物氩。氩-氩方法还依赖于在核反应堆中照射未知样品，以便通过n，p核反应将一些39 K转化为39 Ar。已知年龄的校准标准品与样品同时辐照。通过该方法报告的所有年龄的精密度由已知标准品的精密度确定。该奖项将提供部分资金，使美国国家标准与技术研究所（NIST）和美国地质调查局的工作人员能够采用最先进的方法来生产最可靠的矿物标准，用于氩-氩测年的实验室间校准。该标准将通过NIST的标准参考材料计划分发给地质年代学研究团体。* 9406684约翰逊该奖项提供部分资金，用于支持一名技术人员，该技术人员被分配到麦迪逊的威斯康星州大学地质与地球物理系放射性同位素实验室。该技术员将协助操作和维护实验室设备，其中包括一台多接收器热电离质谱仪和用于样品制备和数据分析的相关仪器。该实验室是大量校内和校外研究人员在地球科学研究和教学项目中所需的质谱分析资源。研究应用包括北冰洋沉积物、地幔地球化学、火山作用、密歇根盆地和威斯康星州拱省的碳酸盐地质年代学以及太古代和元古代花岗岩。该技术员还将参与实验室的技术开发工作，包括开发定量测量铪同位素的新方法。***