Silver deposits, melt-inclusions, isotopes, and thermobarometry

银矿床、熔体包裹体、同位素和温压测定

• 批准号: RGPIN-2015-03912
• 负责人: Marshall, Dan
• 金额: $ 1.97万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=658835
• 关键词: Silver; deposits; melt; inclusions; isotopes

The objective of the proposed research program is to develop an enhanced understanding of how silver is speciated, transported, partitioned, and precipitated in a variety of hydrothermal environments. A series of experiments will be undertaken to test: 1) the existence of low-temperature silver-alloy melts; 2) the indirect measurement of melting temperatures of silver melt inclusions by Surface Enhanced Raman Spectroscopy (SERS); and 3) the feasibility of a using silver isotopes as a geothermometer and a fluid tracer. ***The first hypothesis we will test is whether silver, bismuth, and other metals can be mobilized as melts in relatively low temperature saline brines. This will be investigated via a series of piston cylinder hydrothermal experiments on silver, bismuth and other metals, and the trapping of synthetic melt and fluid inclusions. A second study will test the premise of using the 1010-fold signal strength increase of SERS, relative to standard Raman analysis, as an indirect method of determining melting temperatures of Raman inactive precious metals such as silver and gold in fluid and melt inclusions. Some of the experimental run products will be used, along with natural materials, to investigate the partitioning of 107Ag and 109Ag isotopes to determine the applicability of silver isotopes as a geothermometer. This isotope research will include the development of a protocol for silver isotope extraction from a number of economically important silver-bearing minerals. Calibration of the geothermometer will be based on the fractionation between naturally and synthetically produced mineral pairs relative to a well-characterized international silver isotope standard (NIST SRM978a), measured by high-resolution secondary ion and multi-collector inductively coupled plasma mass spectrometry. ***This research program builds upon my existing expertise in ore deposits, ore petrology, fluid and melt inclusions, isotopes, and experimental work and continues existing research partnerships with researchers from Australian National University and Geoscience Australia. My research team will develop and utilize new research tools and techniques to better characterize pressure, temperature, and timing of fluid mineralizing events, and advance our understanding of the role of fluid and metal melts in silver deposit formation. The results will help to improve our understanding of the evolution of the fluids in Earth's crust, establish their relationship to tectonic and mineralizing events and enhance exploration models for silver deposits. This research program will also train next generation HQP skilled in geochemistry, ore deposits, fluid inclusions, and mineral exploration. This program will integrate our existing industry partnerships, but also create new opportunities to collaborate with industry that will enhance our research and create career opportunities for my students.**

提出的研究计划的目的是提高对银在各种热液环境中如何形成、运输、分区和沉淀的理解。将进行一系列实验来检验：1)低温银合金熔体的存在；2)用表面增强拉曼光谱（SERS）间接测量银熔体包裹体的熔化温度；3)银同位素作为地温计和流体示踪剂的可行性。***我们将测试的第一个假设是银、铋和其他金属是否可以在相对低温的盐水中作为熔体被动员。这将通过一系列对银、铋和其他金属的活塞缸热液实验，以及合成熔体和流体包裹体的捕获来研究。第二项研究将测试使用相对于标准拉曼分析的1010倍信号强度增加的SERS作为间接方法来确定流体和熔体中拉曼非活性贵金属（如银和金）的熔化温度的前提。一些实验产品将与天然材料一起用于研究107Ag和109Ag同位素的分配，以确定银同位素作为地温计的适用性。这项同位素研究将包括制定从一些经济上重要的含银矿物中提取银同位素的方案。地温计的校准将基于天然和合成矿物对之间的分馏，相对于表征良好的国际银同位素标准（NIST SRM978a），通过高分辨率二次离子和多收集器电感耦合等离子体质谱法测量。***该研究项目建立在我在矿床、矿石岩石学、流体和熔体包裹体、同位素和实验工作方面的现有专业知识基础上，并继续与澳大利亚国立大学和澳大利亚地球科学研究所的研究人员建立现有的研究伙伴关系。我的研究团队将开发和利用新的研究工具和技术来更好地表征流体矿化事件的压力，温度和时间，并推进我们对流体和金属熔体在银矿床形成中的作用的理解。研究结果将有助于提高我们对地壳流体演化的认识，建立它们与构造和成矿事件的关系，并改进银矿的勘探模式。该研究项目还将培养地球化学、矿床、流体包裹体和矿产勘探方面的下一代HQP技能。这个项目将整合我们现有的行业合作伙伴关系，同时也创造新的机会与行业合作，这将加强我们的研究，并为我的学生创造就业机会