Laser Microsampling and High Resolution Geochronology Using MC-ICPMS

9526344该项目将开发电感耦合等离子体磁扇区多收集器质谱学新技术，应用于岩石学和地球化学的两个相关领域--更高分辨率的年代学和精确的原位同位素测量。MC-ICPMS结合了非常有效的等离子体电离的优点和多收集器磁扇形质谱的精确度。激光的加入促进了需要空间分辨率的研究。私家侦探们将把开发工作的重点放在新技术上，这种技术提供了其他方法无法很好地复制的能力。特别是在低230Th/232Th样品的高灵敏度U-Th测量、小样品的Hf同位素研究以及高精度的激光原位锶、铅和Hf同位素测量中，将使用MC-ICPMS。在第一个例子中，P.I.s建议使用这些方法来研究流体包裹体的锶和铅同位素，使用高精度的原位同位素测量来阐明岩浆历史，研究火成岩系统的U-Th不平衡，研究锆石的Hf同位素，以及利用微观矿物包裹体来确定P-T-时间路径。

9526344 Halliday This project will develop the new technique of ICP magnetic sector multiple collector mass spectrometry (MC-ICPMS) for application in two areas of relevance to petrology and geochemistry - higher resolution geochronology and precise in situ isotopic measurements. MC-ICPMS combines the advantages of very efficient plasma ionization with the precision of multiple collector magnetic sector mass spectrometry. The addition of a laser facilitates studies for which spatial resolution is needed. The P.I.s will focus their development work in new techniques that provide a capability not well duplicated by other methods. In particular, high sensitivity U-Th measurements on low 230Th/232Th samples, Hf isotopic studies of small samples and high precision in situ laser Sr, Pb, and Hf isotopic measurements will be made with MC-ICPMS. In the first instance the P.I.s propose using these methods for Sr and Pb isotopic studies of fluid inclusions, elucidating magmatic histories using high precision in situ isotopic measurements, U-Th disequilibrium studies of igneous systems, Hf isotopic studies of zircons and the determination of P-T-time paths using microscopic mineral inclusions.