Acquisition of a State-of-the-Art Multi-Collector Inductively-Coupled Plasma Mass Spectrometer

该项目支持马里兰州大学帕克分校地质系购置一台新的、最先进的多接收器电感耦合等离子体质谱仪。这种类型的仪器使用高温等离子体来有效地消除给定材料样品中的元素，从而可以非常精确地确定不同化学元素的相对丰度。 该仪器具有多个检测器，用于同时量化给定元素的不同同位素的离子束强度，从而实现高精度同位素分析。新仪器正在取代老化（17岁），越来越不可靠，我们目前使用的第一代Nu等离子体仪器，并将促进当前NSF赞助的研究，以及预期的未来研究需求。该仪器将用于对一些化学元素的同位素组成进行高精度测量。这些测量用于研究地球的化学演化、岩石和流体之间的相互作用以及成矿过程等。所要求的仪器将允许马里兰州大学的研究人员精确测量从含有相对低浓度这些元素的岩石中提取的Li、Sr、Pb和Ru的同位素组成，还将使人们能够继续利用同位素稀释法对各种地幔和地壳岩石中亲铁元素丰度进行高精度测量。拟议的新MC-ICP-MS仪器将处理的具体分析任务包括：1）地幔和地壳岩石（包括俯冲带相关岩石）的高精度Li同位素分析，作为研究地壳中流体流动和大陆风化历史的一种手段，2）亲铁元素丰度的高精度测量，以约束早期地球历史中硅酸盐储层的起源和演化，研究部分熔融和地幔交代作用对地幔和地壳化学演化的作用; 3）地壳岩石中Pb同位素作为生热制约手段的研究。这些任务中的每一个方面目前都得到了美国国家科学基金赠款，也很可能成为我们小组未来研究的目标。

This project is supporting the acquisition of a new, state-of-the-art Multi-Collector Inductively-Coupled Plasma Mass Spectrometer (MC-ICP-MS) for the Department of Geology of the University of Maryland at College Park (UMD). This type of instrument uses a high temperature plasma to efficiently ionize elements in a given sample of material so that the relative abundances of different chemical elements can be determined very precisely. The instrument has multiple detectors which are used to simultaneously quantify the intensity of ion beams of different isotopes of a given element, allowing high precision isotopic analysis. The new instrument is replacing an aging (17 year old), increasingly unreliable, first generation Nu Plasma instrument we currently utilize, and will facilitate current NSF-sponsored research, as well as anticipated future research needs. The instrument will be used to make high precision measurements of the isotopic compositions of a number of chemical elements. These measurements are used to study, for example, the chemical evolution of the Earth, interactions between rocks and fluids, and ore formation processes.The requested instrument will permit researchers at the University of Maryland to precisely measure the isotopic compositions of Li, Sr, Pb, and Ru extracted from rocks hosting comparatively low concentrations of these elements, and will also allow continued pursuit of high precision measurements of siderophile element abundances in various mantle and crustal rocks by means of the isotope dilution method. Specific analytical tasks to be tackled with the proposed new MC-ICP-MS instrument include: 1) high precision Li isotopic analysis of mantle and crustal rocks, including subduction zone related rocks, as a means of studying fluid flow in the crust and the weathering history of the continents, 2) high precision measurement of siderophile element abundances to constrain the origin and evolution of silicate reservoirs in early Earth history, as well as to study the roles of partial melting and mantle metasomatism on the chemical evolution of the mantle and crust, and 3) the study of Pb isotopes in crustal rocks as a means of constraining heat production. Aspects of each of these tasks are currently supported by NSF grants, and are also likely to be targeted by future research of our group.