Metal sources for hydrothermal deposits : assessing the magmatic contribution

本研究旨在探讨热液矿床中金属的成因。了解这些类型矿床中的金属来源，既影响我们对成矿过程的科学理解，也影响我们发现识别和评估新勘探目标的创新方法。这些矿床的金属来源是一个有很大争议的问题，有两种流行的理论：1)热液来源，金属来源于热水（高达350摄氏度）穿过地球表面下岩石的裂缝和孔隙，热水和岩石之间的相互作用导致金属转移到流体中；或者，2)岩浆源，在那里，金属被熔化的岩浆中的气体和流体所隔离。这项研究将确定金属从岩浆中移出并转移到地球表面深处的气体-水成分的程度。在这项研究中获得的基本信息是熔体包裹体的化学成分，火山玻璃的小残余物，火山爆发前岩浆中形成的矿物中捕获的气体和水。熔体包裹体分析将通过若干实验研究来补充岩浆和热液流体中金属的化学性质，在这些实验研究中，将在实验室模拟地壳较深层的高温和压力条件。为了获得天然熔体包裹体和实验产物的准确成分，需要使用最先进的高精度地球化学仪器的几种分析技术。这项研究将成为湖首大学几个本科生和研究生研究项目的基础，这将通过培养高素质的地球科学家使加拿大受益。这项研究的应用性质将使采矿和勘探部门受益，因为它提高了我们对金属矿藏形成过程的了解，可用于制定发现和可持续发展的新战略。

The proposed study is to investigate the origin of metals in hydrothermal deposits. Knowing where metals in these types of deposit orginate from impacts both our scientific understanding of ore formation processes and the discovery of innovative methods for the identification and evaluation of new exploration targets. The source of metals for these deposits is a matter of great debate, with two prevailing theories: 1) hydrothermal sources, where metals originate from the passage of hot waters (up to 350 degC) through cracks and pores within the rocks beneath Earth's surface, with interaction between the hot water and the rock resulting in the transfer of metals to the fluid; or, 2) magmatic sources, where metals are sequestered by gases and fluids trapped within the molten magma. This study will determine the extent to which metals are removed from the magma and transferred to the gas-water component at great depths beneath the Earth's surface. The fundamental information to be obtained in the study is the chemical compositions of melt inclusions, small remnants of volcanic glass, gas and water trapped in minerals that formed in the magma prior to eruption. Melt inclusion analyses will be complemented by investigating the chemical nature of metals in magmas and hydrothermal fluids through several experimental studies, where the high-temperature and pressure conditions that characterize the deeper levels of the Earth's crust will be simulated in the laboratory. Several analytical techniques using state-of-the-art, high precision geochemical instrumentation will be required to obtain accurate compositions of natural melt inclusions and experimental products. This study will form the basis of several undergraduate and graduate research projects at Lakehead University, which will benefit Canada by training highly qualified geoscientists. The applied nature of the research will benefit the mining and exploration sector by improving our understanding of processes involved in the formation of metallic mineral deposits, which can be used to develop new strategies for their discovery and sustainable development.