Lithium Isotope Studies of Continental Crustal Fluids

Chan 9506390 大陆环境中锂的同位素地球化学几乎是未知的。 这项研究旨在研究锂及其两种同位素6Li和7 Li在大部分大陆地壳中的卤水和沃茨的行为。 将研究三种主要类型的地壳流体：沉积盆地中的地下卤水、太古代地盾中的深层卤水和大陆地热流体。 这一项目包括的代表性例子是以色列的约旦裂谷和油田卤水、加拿大和芬诺斯堪的纳维亚地盾的盐水沃茨以及黄石系统的地热沃茨。 目的是（1）确定不同环境的卤水和热水沃茨及其伴生岩石和沉积物的锂同位素组成;（2）通过水/岩相互作用的实验室模拟确定元素分配系数和同位素分馏因子;（3）应用研究结果模拟地壳流体的起源和演化。 特别强调的是盐度的原因和盐水的氯化钙成分，这仍然是一个相当大的辩论的主题。Li同位素系统学将与更成熟的同位素示踪剂87 Sr/86 Sr和34 S/32 S进行比较。 此外，还将分析所有沃茨的主要和次要成分（N、K、Ca、Mg、Sr、Li、Cl、SO 4、HCO 3和NO 3），以便综合解释母流体的性质以及与寄主岩石相互作用过程的影响。 这项工作将与A博士合作。来自耶路撒冷希伯来大学的Katz。 该研究的意义在于为大陆地壳沃茨的研究建立了一个新的同位素体系。 同时，也将大大丰富可靠的锂同位素数据，有助于对锂同位素地球化学的基础性认识。 对大陆垫铁的研究将补充最近的海洋研究，以便更全面地了解锂同位素的陆地变化。

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.