RUI: Pressure-temperature Constraints and Fluid Evolution for Sediment-hosted Gold and Intrusion-related Mineralization, Getchell, Nevada

本文的主要目标是：1)确定卡林型金矿床的形成条件；2)在时间上将盖切尔金系统与邻近的90 Ma花岗闪长岩侵入体及其成矿作用联系起来或分离出来。这些目标将通过1)对金系统进行详细的岩石学和流体包裹体研究，以约束地层压力、温度和水流体化学；2)对与花岗闪长岩侵入相关的石英脉和钨矽卡岩成矿进行详细的岩石学和流体包裹体研究，以获得类似的约束条件。流体包裹体将通过显微测温和显微分析进行评估，包括拉曼光谱、四极杆质谱和离子色谱。Getchell系统为详细研究carlin型矿床的物理/化学演化提供了独特的机会。初步结果表明，流体包裹体适用于显微测温、拉曼光谱和四极杆质谱分析。本研究将记录卡林型系统中有利于金沉淀的物理/化学条件以及金成矿与火成岩活动的关系。研究结果将在时间上把金矿化与侵入体相关的成矿作用联系起来或分离开来，并对卡林型金矿的成矿年龄有重要的约束作用。

The primary goals of this proposal are: 1) to determine the formation conditions of a Carlin-type gold deposit, and 2) to either link or separate in time the Getchell gold system and an adjacent 90 Ma granodiorite intrusion and related mineralization. These goals will be accomplished by 1) a detailed petrographic and fluid inclusion study of the gold system to constrain formation pressures and temperature and aqueous fluid chemistry, and 2) a detailed petrographic and fluid inclusion study of quartz veins and tungsten skarn mineralization related to the granodiorite intrusion, to obtain similar constraints. Fluid inclusions will be evaluated by microthermometry and microanalyses including Raman spectroscopy, quadrupole mass spectrometry, and ion chromatography. The Getchell system provides a unique opportunity to examine, in detail, the physical/chemical evolution of a Carlin-type deposit. Preliminary results demonstrate that fluid inclusions present are suitable for microthermometry, Raman spectroscopy, and quadrupole mass spectrometry. This study will document the physical/chemical conditions conducive to gold precipitation and the relationship between gold mineralization and igneous activity in Carlin-type systems. Results will link or separate in time the gold- and intrusion-related mineralization and may place important constraints on the age of gold mineralization in a Carlin-type deposit.