Experimental Study of HC1 in Magmatic-Hydrothermal Systems

矿床和有关的矿物蚀变常与富硅火成岩有关。 这些火成岩侵入体被假设为演化出一种或多种富含水和氯的流体相，这有助于矿物蚀变和附近的矿石沉积。 岩浆挥发相中的盐酸（HCl）浓度已被证明影响矿物的稳定性，金属的行为和矿石沉淀的机制。 HCl影响这些过程的程度是未知的，因为缺乏实验数据来测试目前的假设在何种程度上挥发相影响矿物蚀变和金属运输。 将进行一系列实验来解决这种基础知识的缺乏。 本研究将研究HCl在岩浆热液系统的压力和温度下的活性，600- 750 ℃，其中金属从结晶长英质熔体中分离出来，并沉积在系统的高温部分。 此外，拟议的研究将汇编有关选定矿物系统中高盐度盐水和超临界流体中HCl活性的重要数据。 我们的研究将在600- 750 ℃和50-140 MPa的温度下，在蒸汽-不饱和盐水和超临界流体相场的一系列盐度范围内共同解决这些系统，并应用于更广泛的岩浆热液系统。 一名本科生和一名研究生将参加本研究项目，并将接受实验地质学、热力学和地球化学方面的培训。 研究生还将指导参与该项目的更多初级成员。 该研究成果可为改进现有的高温矿床金属勘查模式提供直接的经济效益。

Ore deposits and related mineral alteration are often associated with silica-rich igneous rocks. These igneous intrusions have been hypothesized to evolve one or more water and chlorine-rich fluid phases, which contribute to mineral alteration and nearby ore deposition. The hydrochloric acid (HCl) concentration within this magmatic volatile phase has been shown to influence mineral stability, the behavior of metals and the mechanisms of ore precipitation. The extent to which HCl influences these processes is unknown because there is a dearth of experimental data with which to test current hypotheses on the extent to which volatile phases influence mineral alteration and metal transport. A succession of experiments will be conducted to address this lack of fundamental knowledge. This study will examine the activity of HCl at pressures and temperatures of the magmatic-hydrothermal system, 600-750C, where metals are partitioned from a crystallizing felsic melt and deposited in the high-temperature portion of the system. Additionally, the proposed research will compile important data regarding the activity of HCl in both high-salinity brines and supercritical fluids in select mineral systems. Our study will address these systems collectively over a range of salinities within the vapor-undersaturated brine and supercritical fluid phase fields at temperatures from 600-750C and 50-140 MPa with applications to the broader magmatic-hydrothermal system. An undergraduate student and a graduate student will participate in this research project and will be trained in experimental geology, thermodynamics, and geochemistry. The graduate students will also mentor the more junior members involved in this project. The results of this research can provide direct economic benefits by improving existing metal exploration models associated with high-temperature ore deposits.