Boron Isotopic Studies of Hydrothermal Fluids and AssociatedVein Mineralization

这项SGER奖的目的是在Salton Sea、COSO和间歇泉地热田启动一项关于热液卤水的良好特征样品和相关脉状矿化之间的B同位素分馏的合作研究。这项研究将用来评估几种常见的蚀变矿物及其沉淀流体之间的B元素和同位素分配。利用为这些油田的商业地热井建立的储集层特征，也可以对温度对这种划分的影响进行经验校准。从本质上讲，它计划使用自然系统作为一种实验校准形式。这一方法将对各种热液矿物中的硼浓度(以及对每种矿物进行硼同位素分析的可行性)进行一次重要的调查，并将重点放在那些最有实际应用潜力的矿物种类上进行详细的实验。同位素测量将在国家标准与技术研究所与R.vocke合作进行，R.vocke的研究小组最近开发了一种改进的B同位素质谱分析方法。建议首先分析M.A.McKibben以前收集的选定流体样品，以改进同位素分析方法，然后访问每个地热田的代表性井，进一步取样流体和脉状矿化(从岩心和岩屑中)。

The purpose of this SGER award is to initiate a collaborative investigation of B isotopic fractionation between well characterized samples of hydrothermal brines and associated vein mineralization at the Salton Sea, Coso, and Geysers geothermal fields. This study will serve to evaluate both B elemental and isotopic partitioning between several common alteration minerals and the fluids from which they precipitated. Empirical calibration of temperature effects on such partitioning is also possible using reservoir characteristics established for commercial geothermal wells in these fields. Essentially, it is planned to use the natural systems as a form of experimental calibration. This approach will provide an important survey of B concentrations in a variety of hydrothermal minerals(and of the feasibility of B isotopic analysis in each) that will focus subsequent detailed experimentation on those mineral species having the greatest potential for practical applications. Isotopic measurements will be carried out at the National Institute for Standards and Technology in collaboration with R. Vocke whose research group has recently developed an improved method for B isotopic mass spectrometry. It is proposed to first analyze selected fluid samples previously collected by M.A. McKibben to refine methods for isotopic analysis, then to visit representative wells from each of the geothermal fields for further sampling of fluids and vein mineralization (from core and cuttings).