Chemical fingerprinting and tracing of fluids in hydrothermal ore deposit systems

热液矿床系统中流体的化学指纹识别和追踪

• 批准号: RGPIN-2020-05013
• 负责人: Kontak, Daniel
• 金额: $ 2.62万
• 依托单位: Laurentian University of Sudbury
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740347
• 关键词: Chemical; fingerprinting; tracing; fluids; hydrothermal

A wide spectrum of hydrothermal ore-deposit settings (high-T magmatic to low-T diagenetic) are important for a wide variety of metals used to sustain the needs of our modern and continually evolving society. Exploration for resources depend to a large extent on successful mineral exploration, which itself relies on ore-deposit models at different scales; to be effect such models need constant refining. The latter results from the ongoing iteration of many observations which begin in the field and extend to the laboratory where extensive study and analyses occur using the most up-to-date analytical equipment. In addition, as hydrothermal ore deposits represent highly anomalous concentrations of metals, they reflect unusual processes in the Earth's crust. Thus improving our understanding ore-deposit phenomena also contributes to furthering our knowledge of Earth systems on different scales through time in regards to the lithosphere, hydrosphere and atmosphere. My research group uses an integrated field and geochemical approach for a number of ore deposit types (e.g., orogenic and intrusion-related Au,, porphyry (Cu-Au, Sn, rare metals), pegmatites (Li), low T sedimentary-rock hosted (Zn-Pb, Cu)). This approach relies in part on using the chemical signal preserved in both fluid inclusions (<10-50 um size fluid aliquots) hosted in minerals and also mineral phases themselves (e.g., pyrite, scheelite); both can be used as proxies for ore forming processes. The intent of the current proposal is to use the advances made by my research group and modern analytical technology, such as LA ICP-MS, to further explore our understanding of gold deposit settings. The approach used is a fluid-chemical one and relies on the recent advances in several instruments that provide the capability to analyse phases at the micron scale. For example, we can now acquire both the age of formation and geochemical signature for several single mineral phases relevant to ore systems, e.g., scheelite (W), tantalite (Ta, Nb), cassiterite (Sn). Scheeite is of particular importance to this study as it is a common phase in different gold systems which allows them to be contrasted. The project will address the application of the methodology in three graduate student projects specifically addressing issues related to better characterizing the fluids and mineral phases (e.g., scheelite, arsenopyrite) in gold systems in order to better discriminate gold deposit types, in particular the orogenic and intrusion-related clans. Data generated will be used to  further develop robust mineral deposit models for the latter gold deposit settings and better define the overall deposit genesis and thus Earth system processes at different scales. The three projects described below are discrete in their method, but overlap in intent and deposit types. Importantly, the methodology used can be transferred to other ore-deposit settings and thus has widespread application to ore systems in general.

广泛的热液矿床环境（高t岩浆到低t成岩）对于维持现代和不断发展的社会所需的各种金属非常重要。矿产勘查的成功与否在很大程度上取决于矿产勘查的成功与否，而矿产勘查本身就依赖于不同规模的矿床模式；要想发挥作用，这些模型需要不断完善。后者的结果是许多观察的不断迭代，这些观察从实地开始，延伸到实验室，在那里使用最先进的分析设备进行广泛的研究和分析。此外，由于热液矿床代表了高度异常的金属浓度，它们反映了地壳中不寻常的过程。因此，提高我们对矿床现象的理解也有助于我们进一步了解不同尺度的地球系统，包括岩石圈、水圈和大气。我的研究小组对许多矿床类型（例如，造山和侵入相关的Au，斑岩（Cu-Au, Sn，稀有金属），伟晶岩（Li），低T沉积岩（Zn-Pb, Cu））使用综合场和地球化学方法。该方法部分依赖于利用保存在矿物中的流体包裹体（<10-50 μ m大小的流体同分液）和矿物相本身（如黄铁矿、白钨矿）中的化学信号；两者都可以作为成矿过程的代理。本次提案的目的是利用我的研究小组取得的进展和现代分析技术，如LA ICP-MS，进一步探索我们对金矿床环境的认识。所使用的方法是一种流体化学方法，并依赖于几种仪器的最新进展，这些仪器提供了在微米尺度上分析相的能力。如白钨矿(W)、钽钨矿（Ta、Nb）、锡钨矿（Sn）等与矿系相关的单矿物相的形成年龄和地球化学特征。Scheeite对这项研究特别重要，因为它是不同金体系中的共同相，可以对它们进行对比。该项目将在三个研究生项目中应用该方法，具体解决与更好地描述金系统中的流体和矿物相（例如白钨、毒砂）有关的问题，以便更好地区分金矿类型，特别是造山带和与侵入有关的部族。所产生的数据将用于进一步为后一种金矿设置建立可靠的矿床模型，并更好地定义总体矿床成因，从而在不同尺度上确定地球系统过程。下面描述的三个项目在方法上是离散的，但在意图和矿床类型上是重叠的。重要的是，所使用的方法可以转移到其他矿床环境，从而广泛应用于一般的矿石系统。