Lithium Isotope Studies of Continental Crustal Fluids

大陆地壳流体的锂同位素研究

• 批准号: 9506390
• 负责人: Lui-Heung Chan
• 金额: $ 15.23万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-01 至 1999-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9506390&HistoricalAwards=false
• 关键词: Lithium; Isotope; Studies; Continental; Crustal

Chan 9506390 The isotope geochemistry of lithium in the continental environments is virtually unknown. The proposed research is intended to examine the behavior of lithium and its two isotopes 6Li and 7Li in brines and waters which reside in a large part of the continental crust. Three major types of crustal fluids will be studied: subsurface brines in sedimentary basins, deep seated brines saturating Archean Shields, and continental geothermal fluids. Representative examples to be included in this project are the Jordon Rift and oil field brines of Israel, saline waters from the Canadian and Fennoscandian shields and the geothermal waters from the Yellowstone system. The objectives are (1) to establish the lithium isotope composition of brines and thermal waters from various environments and of their associated rocks and sediments, (2) to determine element distribution coefficient and isotope fractionation factors by laboratory simulation of water/rock interaction, and (3) to apply the findings to model the origin and evolution of the crustal fluids. Special emphasis will be given to the cause of salinity and the calcium chloridic composition of the brines which remains a subject of considerable debate. Li isotope systematics will be compared to the more established isotope tracers, 87Sr/86Sr and 34S/32S. In addition, all waters will be analyzed for the major and minor constituents (N, K, Ca, Mg, Sr, Li, Cl, SO4, HCO3, and NO3) for an integrated interpretation of the nature of the parent fluid and the effects of interactive processes with the host rock. This work will be in collaboration with Dr. A. Katz of Hebrew University, Jerusalem. The significance of the proposed research lies in the establishment of a new isotope system for the study of continental crustal waters. At the same time, it will leas to a considerable enlargement of reliable lithium isotope data and contribute to the fundamental understanding of the isotope geochemistry of lithium. The study of continental mat erial will complement the recent marine studies to offer a more comprehensive view of the terrestrial variation of lithium isotopes.

Chan 9506390 大陆环境中锂的同位素地球化学几乎是未知的。 拟议的研究旨在研究锂及其两种同位素 6Li 和 7Li 在位于大陆地壳大部分区域的盐水和水中的行为。 将研究三种主要类型的地壳流体：沉积盆地中的地下盐水、太古代地盾的深层盐水和大陆地热流体。 该项目的代表性例子包括以色列的约旦裂谷和油田盐水、加拿大和芬诺斯堪地盾的盐水以及黄石系统的地热水。 目标是（1）确定来自不同环境的盐水和热水及其相关岩石和沉积物的锂同位素组成，（2）通过水/岩石相互作用的实验室模拟来确定元素分布系数和同位素分馏因子，以及（3）应用这些发现来模拟地壳流体的起源和演化。 将特别强调盐度的成因和盐水中的氯化钙成分，这仍然是一个颇有争议的话题。 Li 同位素系统学将与更成熟的同位素示踪剂 87Sr/86Sr 和 34S/32S 进行比较。 此外，将对所有水体的主要和次要成分（N、K、Ca、Mg、Sr、Li、Cl、SO4、HCO3 和 NO3）进行分析，以综合解释母液的性质以及与母岩相互作用过程的影响。 这项工作将与耶路撒冷希伯来大学的 A. Katz 博士合作。 该研究的意义在于为研究大陆地壳水域建立了一个新的同位素系统。 同时，它将大大增加可靠的锂同位素数据，并有助于对锂同位素地球化学的基本了解。 对大陆物质的研究将补充最近的海洋研究，以提供有关锂同位素陆地变化的更全面的观点。