Controls on fluid flow and metal deposition in sediment-hosted hydrothermal ore deposits

沉积型热液矿床是全球许多金属的重要来源，包括铜、钴、铅、锌、铀、砷和锗。以沉积物为主的矿床很难发现，因为它们具有“隐蔽的”矿物蚀变（即肉眼看不见的蚀变）。此外，形成高品位矿床的过程是不确定的。这意味着需要新的地球化学工具来识别和绘制这些矿床的关键过程和蚀变足迹。在热液穿过岩石的过程中，会形成一系列的反应锋面。这些反应前沿将表现为矿石金属丰度、矿化蚀变、稳定同位素比值和温度的变化。准确绘制温度变化图是困难的，指标蚀变矿物（如伊利石、黑云母）不能提供足够的温度精度，并且流体包裹体通常不能很好地保存在沉积物含热液矿床中。该研究项目将开发新的方法，利用团块碳和氧同位素，对高达350摄氏度的碳酸盐矿物进行精确的温度测量。该计划将开发新的方法和数据集，用于量化沉积矿床内不同尺度（从薄片到矿床尺度）的蚀变矿物学和初级和次级结构的变化，以创建新的矿床模型。最后，我们将寻求测试和开发新的沉积型铜矿的勘探工具，重点是识别磷灰石、金红石和独居石等抗蚀性指示矿物的独特结构和化学性质。总的来说，这一研究项目将发展关于沉积物矿床成因和蚀变的基本新知识，开发适合发现新矿床的新勘探工具和方法，并培养高素质的人才，这些人才将为低碳能源转型提供所需的矿产资源。

Sediment-hosted hydrothermal ore deposits represent globally significant sources for many metals including copper, cobalt, lead, zinc, uranium, arsenic and germanium. Sediment-hosted deposits are difficult to discover because they have "cryptic" mineral alteration (i.e. alteration invisible to the eye). In addition, processes responsible for forming high-grade ore deposits are uncertain. This means that new geochemical tools are required that will enable recognition and mapping of the key processes and alteration footprints for these deposits. During the flow of hydrothermal fluid through rock, a series of reaction fronts will be established. These reaction fronts will manifest as changes in ore metal abundances, mineralogical alteration, stable isotope ratios and temperature. Accurate mapping of temperature variations is difficult, with index alteration minerals (e.g. illite, biotite) providing insufficient temperature precision, and fluid inclusions often not well preserved in sediment-hosted hydrothermal deposits. This research program will develop new methods for providing precise temperature measurements from carbonate minerals formed at up to 350 oC  utilizing clumped carbon and oxygen isotopes. The program will develop new methods and datasets for quantifying alteration mineralogy and variations in primary and secondary textures across scales (from the thin section to deposit scale) within sediment-hosted ore deposits in order to create new ore deposit models. Finally, we will seek to test and develop new exploration tools for sediment-hosted copper deposits focussing on recognizing unique textures and chemistry of resistate indicator minerals such as apatite, rutile and monazite. Collectively, this research program will both develop fundamental new knowledge on the genesis and alteration of sediment-hosted ore deposits, develop new exploration tools and methods suitable for discovering new deposits, and train the highly qualified personnel who will be needed to deliver the mineral resources required for the low-carbon energy transition.