Acquisition of a Thermal Ionization Mass Spectrometer at the Berkeley Geochronology Center

这项资助通过学术研究基础设施（ARI）计划提供了20万美元，作为购买最先进的、高丰度灵敏度的热电离质谱仪（TIMS）的部分费用支持，该质谱仪有多个收集器，用于铀系列和U-Th- Pb地质年代学。具体项目将包括硅质微化石、成土二氧化硅和碳酸盐、洞穴主题、珊瑚和考古遗址的牙釉质等材料的定年，使用U系列方法对20-500 Ka年龄范围的样品进行定年，使用U/Pb技术对中生代前火成岩副相进行定年。这些数据将为晚更新世海洋地层记录提供新的时代控制，为含蛋白石土壤的成土时间和气候历史提供新的时代控制，为巨质方解石中记录的古气候提供高分辨率记录，并为根据近地表居住珊瑚（如Acropora palmata）的u系列测年确定的精确地质年代学提供古海平面记录。新的TIMS还将用于校准斯坦福大学-美国地质调查局的SHRIMP离子微探针对单个锆石的分析，并将提供火山锆石的40Ar/39Ar日期的独立检查，以及使用BGC现有的惰性气体质谱仪获得的sanidines。该TIMS的资金也将与美国国家科学基金会的考古计划（SBR-9601068）共享。＊＊＊

9601975 Ludwig This grant, made through the Academic Research Infrastructure (ARI) Program, provides $200,000 as partial support of the costs of acquiring a state- of-the-art, high abundance sensitivity, thermal ionization mass spectrometer (TIMS) with multiple collectors, to be used for Uranium series and U-Th- Pb geochronology. Specific projects will include the dating of siliceous microfossils, pedogenic silica and carbonate, speleothems, corals and materials from archaeological sites such as tooth enamel using U-series methods for samples in the 20-500 Ka age range and U/Pb techniques for dating of pre-Mesozoic igneous accessory phases. These data should provide new age controls on the late Pleistocene marine stratigraphic record, the timing of pedogenesis and thus climate history of opal-bearing soils, high-resolution records of paleoclimate recorded in spleothem calcites and records of paleosea level based on accurate geochronologies determined from U-series dating of near-surface dwelling corals such as Acropora palmata. The new TIMS will also serve to calibrate Stanford-USGS SHRIMP ion microprobe analyses of individual zircons and will provide independent checks of 40Ar/39Ar dates of volcanic zircons and sanidines obtained using the existing noble gas mass spectrometer at the BGC. Funding of this TIMS will also shared with NSF's Archaeometry Program (SBR-9601068). ***