Collaborative Research: Stable Isotope Systematics of Gold-silver Telluride Deposits: A Theoretical and Experimental Approach

合作研究：碲化金银矿床稳定碲同位素体系的理论与实验研究本项目的目标是确定含碲矿物的稳定碲同位素体系，主要是在Au-Ag-Te体系中（在浅成热液型和造山型金矿床中），以确定这些贵金属矿床中碲的来源（以及可能伴生的金和银）、与同位素分馏有关的过程、与矿床成因有关的地球化学信息以及对碲的化学性质有更好的了解。还将解决的一个问题是：稳定的碲同位素能否以以前使用其他稳定同位素（例如，氧和铜）？该项目的目标将通过分析碲化物、自然碲、碲酸盐和碲酸盐的稳定碲同位素来实现，这些同位素将从各种造山和浅成热液金（例如，Golden Sunlight and Mayflower，Montana; Emperor and Tuvatu，Fiji;肯辛顿，Alaska; Golden Mile，Western Australia），使用多收集器电感耦合等离子体质谱仪（MC-ICPMS）系统使用原位和溶液方法。该研究将具体评估：1。产生质量依赖性同位素分馏的机制，包括生物或非生物过程（例如，氧化还原行为）、液-气分离（因为碲在液相和气相中传输）、动力学、沉积和传输过程。同位素分馏的可能性，由质量无关的过程也将被考虑;2。矿床中碲的潜在来源以及关于金形态I矿床可以了解到什么，因为分析的大多数矿物将是Au-Ag-Te系统的成员（calaverite，crennerite，calciumite，hessite，petzite，stützite，empresite，muthmannite）;以及3.利用振动光谱和力场模型通过理论计算确定的同位素组成与从陆地样品的独立地质温度计确定的同位素组成之间的差异。更广泛的影响：除了收集关于热液金矿中稳定碲同位素的系统学和起源的基本数据外，还将获得关于这种元素的基本化学的信息。碲有着广泛的用途（陶瓷，玻璃纤维，硫化橡胶，电子工业），但它主要用于工业中形成铜，铅，铁合金和更可加工的不锈钢。碲也用于太阳能电池板中的碲化镉（CdTe），目前正在研究（Cd，Zn）Te是否可以用作替代品。它在太阳能电池板中的应用对美国和其他地方的替代能源至关重要。该项目还将通过政府机构（美国地质调查局、加拿大地质调查局）和学术界（爱荷华州州立大学、加州大学-洛杉矶）人员之间的合作，加强研究教育的基础设施。它还将为两名博士提供多学科研究机会。学生和本科生谁是在政府，矿业和学术界发展事业感兴趣。

Collaborative Research: Stable Tellurium Isotope Systematics of Gold-Silver Telluride Deposits: A Theoretical and Experimental ApproachIntellectual Merit: The goal of this project is to determine the stable tellurium isotope systematics of tellurium-bearing minerals, primarily in the system Au-Ag-Te (in epithermal and orogenic gold deposits), to determine the source of tellurium in these precious metal deposits (and possibly associated gold and silver), processes associated with isotope fractionation, geochemical information related to the origin of the deposits, and a better understanding of the chemistry of tellurium, in general. A question that will also be addressed is: can stable tellurium isotopes be used in mineral exploration and vectoring new ore bodies in an existing mining camp in a way that has been previously done with other stable isotopes (e.g., oxygen and copper)? The aims of the project will be achieved by analyzing the stable tellurium isotopes of tellurides, native tellurium, tellurates and tellurites, which will be sampled, and for some deposits have already been collected, from various orogenic and epithermal gold (e.g., Golden Sunlight and Mayflower, Montana; Emperor and Tuvatu, Fiji; Kensington, Alaska; Golden Mile, Western Australia), using both in situ and solution methods with a multi collector-inductively coupled plasma-mass spectrometer (MC-ICPMS) system. The study will specifically evaluate:1. Mechanisms that produce mass-dependent isotope fractionation including, biotic or abiotic processes (e.g., redox behavior), liquid-vapor separation (since tellurium is transported in both the liquid and vapor phases), kinetics, deposition and transportation processes. The possibility that isotopes are fractionated by mass-independent processes will also be considered;2. Potential sources of tellurium in ore deposits and what can be learned about gold speciation I deposits, since most of the minerals analyzed will be members of the system Au-Ag-Te (calaverite, krennerite, sylvanite, hessite, petzite, stützite, empressite, muthmannite); and3. Differences between isotope compositions determined by theoretical calculations, using vibrational spectra and force-field models, and those determined from independent geothermometers from terrestrial samples.Broader Impacts: In addition to collecting fundamental data on the systematics of stable tellurium isotopes in and the origin of hydrothermal gold deposits, information will also be obtained on the basic chemistry of this element. Tellurium, has a wide variety of uses (ceramics, glass fiber, vulcanized rubber, electronics industry), but it is used primarily in industry to form copper, lead, and iron alloys and more machinable stainless steel. Tellurium is also used in cadmium telluride (CdTe) in solar panels and research is underway to investigate whether (Cd,Zn)Te can be used as an alternate. Its use in solar panels is critical to the thrust on alternative sources of energy in the United States, and elsewhere. The project will also enhance infrastructure for research education by involving collaborations among personnel in government agencies (United States Geological Survey, Geological Survey of Canada) and academia (Iowa State University, University of California - Los Angeles). It will also provide multidisciplinary research opportunities for two Ph.D. students and an undergraduate student who are interested in developing careers in the government, minerals industry, and academia.