Lithium Isotope Studies of Continental Crustal Fluids

陈9506390大陆环境中锂的同位素地球化学实际上是未知的。这项拟议的研究旨在检查锂及其两个同位素6Li和7Li在居住在大陆地壳大部分地区的卤水和水中的行为。将研究三种主要类型的地壳流体：沉积盆地中的地下卤水、充满太古宙地盾的深层卤水和大陆地热流体。该项目将包括的有代表性的例子是以色列的Jordon裂谷和油田卤水、加拿大和芬诺斯坎迪亚地盾的咸水以及黄石系统的地热水。其目的是(1)确定不同环境中卤水和热水及其伴生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配系数和同位素分馏系数，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卤水的氯化钙成分，这仍然是一个相当有争议的主题。锂同位素系统将与更成熟的同位素示踪剂87Sr/86Sr和34S/32S进行比较。此外，将分析所有水的主要和次要成分(N、K、Ca、Mg、Sr、Li、Cl、SO4、HCO3和NO3)，以综合解释母流体的性质和与主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·卡茨博士合作。这项研究的意义在于建立了一个新的研究陆壳水域的同位素系统。同时，它将使可靠的锂同位素数据得到相当大的放大，并有助于从根本上理解锂的同位素地球化学。大陆物质的研究将补充最近的海洋研究，以提供更全面的锂同位素陆地变化的观点。

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.