The magmatic-hydrothermal conceptual model for Carlin-type gold deposit genesis calls upon deep-seated Eocene plutons as the primary source of gold-bearing fluids. However, geophysical surveys, geologic mapping, drilling, geochronology, isotopic tracers, and fluid inclusion chemistry have returned ambiguous evidence for the existence of such plutons. The high-grade Cortez Hills gold deposit in northern Nevada hosts shallow, Eocene syn- and postmineralization intrusions, offering an ideal site to investigate the existence of a deep-seated pluton beneath the district. Here, major and trace element analyses of quartz-hosted melt inclusions from four Eocene rhyolite dikes cropping out within the Cortez Hills pit and results from independent thermobarometers provide a window into the subsurface Eocene magmatic plumbing system to test the existence of a deep-seated source pluton. Dissolved volatile contents, melt inclusion entrapment pressures, and thermodynamic phase equilibria indicate that dike magmas were sourced from ~4- to ≥9-km depth from a polybaric magma reservoir residing as a physically and geochemically interconnected crystal mush with extractable or eruptible magma pockets. Magmas ascended adiabatically (nearly isothermally), exsolving fluids, evolving modestly by fractional crystallization, while trapping quartz-hosted melt inclusions steadily from depth to subvolcanic levels where they were emplaced. These data represent the first unequivocal evidence for a deep-seated magma reservoir from which fluid-saturated magma emanated and released magmatic fluids beneath the Cortez district during gold mineralization. However, further investigation into the specific metallogenic potential and metal budget of parental magmas and the partitioning of gold between silicate melt and aqueous fluids will be necessary to provide evidence that exsolved magmatic fluids may have been gold bearing.

中文翻译：

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内华达州科尔特斯山下的始新世岩浆管道系统位于卡林型金矿床中：是否存在深层岩浆？

卡林型金矿床成因的岩浆热液概念模型要求深部始新世岩体为含金流体的主要来源。但是，地球物理勘测，地质制图，钻探，年代学，同位素示踪剂和流体包裹化学已经返回了有关存在此类p的模棱两可的证据。内华达州北部的Cortez Hills高品位金矿床拥有浅，始新世同化和矿化后的侵入体，为研究该地区下方深层岩体的存在提供了理想的场所。这里，对来自Cortez Hills坑内的四个始新世流纹岩堤防的石英基质熔体包裹体的主要元素和微量元素分析，以及独立的热压仪提供的结果为深入了解始新世岩浆管道系统提供了一个窗口，以测试深层源岩体的存在。溶解的挥发物含量，熔体包裹体夹带压力和热力学相平衡表明，堤防岩浆来自多巴基岩浆储集层，深度约4至≥9 km，该岩浆体是物理和地球化学互连的结晶浆，具有可提取或可喷出的岩浆袋。岩浆绝热地（几乎等温地）上升，溶解流体，通过分步结晶适度地演化，同时从深部到埋入火山岩的水平稳定地捕获石英承载的熔体夹杂物。这些数据代表了深部岩浆储层的第一个明确证据，在金矿化过程中，饱和流体岩浆从该岩浆中散发出来并释放出科尔特斯地区下方的岩浆流体。但是，有必要进一步研究母体岩浆的特定成矿潜力和金属收支，以及在硅酸盐熔体和水性流体之间分配金，以提供证据表明已溶解的岩浆流体可能含金。