Oxygen Isotope Investigation of the Fossil Hydrothermal System in the Comstock Lode Mining District, Nevada

我建议对内华达州康斯托克洛德矿区火山岩中的氧同位素关系进行详细的研究，那里有一个相对较小的(75平方公里)带，受到大气-热液强烈循环的影响，导致区域橄榄岩作用和重要的浅成热液Au-Ag矿床的形成。氧同位素数据将被用来绘制循环模式图，识别与渗透相关的同位素不平衡效应，并表征古代热液系统中的流体来源和温度分布。地表样品的数据将用矿山采掘样品的数据加以补充，以建立一个重要矿区的热液系统的第一个详细的三维图像。我预计，这项研究将揭示循环模式和地质因素之间的关键关系，这将促进对这些系统的理解，并可能对矿床提供宝贵的指导。这项研究还将增进对本大陆区域地质框架的了解，并将提供有关对流系统参与的地质环境和过程的基本数据。

I propose to make a detailed study of oxygen isotope relations in volcanic rocks in the Comstock lode mining district, Nevada, where a relatively small (75 km2) zone was affected by intense circulation of meteoric-hydrothermal fluid, resulting in regional propylitization and in the formation of important epithermal Au-Ag deposits. Oxygen isotope data will be used to map the circulation pattern, to identify infiltration-related isotopic disequilibrium effects, and to characterize the fluid sources and the temperature distribution in the ancient hydrothermal system. Data from surface samples will be augmented with data on samples from mine workings in order to construct the first detailed 3-dimensional image of a hydrothermal system in an important mining district. I anticipate that the research will disclose critical relationships between circulation patterns and geologic factors that will advance understanding of these systems and that may be invaluable guides to ore deposits. The study will also advance knowledge about the regional geologic framework of our continent, and will provide fundamental data about the geologic environments and processes in which convective systems participate.