Experimental Study of HC1 in Magmatic-Hydrothermal Systems

岩浆-热液系统中HC1的实验研究

• 批准号: 0609880
• 负责人: Mark Frank
• 金额: $ 16.18万
• 依托单位: Northern Illinois University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0609880&HistoricalAwards=false
• 关键词: Experimental; Study; HC1; Magmatic; Hydrothermal

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.

矿床及相关矿物蚀变常与富含二氧化硅的火成岩共生。据推测，这些火成岩侵入岩演化出一种或多种富水和富氯的流体相，这有助于矿物蚀变和附近的矿床沉积。这一岩浆挥发相中的盐酸浓度已被证明影响矿物稳定性、金属行为和成矿机理。HCl对这些过程的影响程度尚不清楚，因为缺乏实验数据来检验目前关于挥发性相对矿物蚀变和金属运输的影响程度的假设。将进行一系列实验，以解决缺乏基本知识的问题。这项研究将考察在600-750摄氏度的岩浆-热液系统的压力和温度下HCl的活性，在该系统中，金属从结晶的长英质熔体中分离出来，并沉积在该系统的高温部分。此外，拟议的研究将汇编有关高盐度卤水和选定矿物系统中超临界流体中HCl活度的重要数据。我们的研究将在600-750摄氏度和50-140兆帕温度下，在蒸汽欠饱和卤水和超临界流体相场内的一系列盐度范围内对这些系统进行集体研究，并将其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与这项研究项目，并将接受实验地质学、热力学和地球化学方面的培训。研究生还将指导更多参与该项目的初级成员。这一研究成果可以通过改进现有的与高温矿床相关的金属勘探模型来提供直接的经济效益。