Genesis of hydrothermal gold deposits

从太古代到整个中生代，造山型金矿的产量约占世界金矿产量的20%。虽然它们的形成被广泛认为是造山旋回晚期热液流体与围岩相互作用的结果，但成矿流体的来源仍然缺乏约束。流体的成因有多种模式，包括变质作用、地幔脱挥发分作用、岩浆作用和大气降水作用。本研究计划提出：（1）评价岩浆流体与变质流体在造山型金矿床成因中的作用;（2）发展更精确的成因模式。这些模型将有助于确定更多的潜在矿化带，从而提高全球黄金勘探的成功几率。 这一目标将通过研究太古代和中生代各造山带中岩浆和变质流体的生成和成分来实现。该研究将侧重于调查（a）与加拿大瓦尔多尔区金矿化共面侵位的花岗岩和（B）新西兰奥塔戈-阿尔卑斯山片岩中缺乏岩浆活动的变质岩中的流体。该研究计划将涉及综合实地和实验室调查，这是为学术界和工业界培养高素质人才的关键。研究结果也有望导致新技术的发展，分析单一的流体包裹体，并将开拓直接识别的微量元素组成的绿片岩和角闪岩相变质岩中的变质流体。

About 20% of the world's cumulative gold production has come from orogenic gold deposits formed from Archean to throughout Phanerozoic. Although their formation is widely recognized as having resulted from the interaction of hydrothermal fluids with country rocks during the late stages of orogenic cycles, the sources of the ore-forming fluids are still poorly constrained. Various models have been proposed for the origin of fluids, including metamorphic, mantle devolatilization, magmatic and meteoric. This research program proposes (1) to evaluate the role of magmatic versus metamorphic fluids in the genesis of orogenic gold deposits and (2) to develop more refined genetic models. Such models will aid in identifying more prospective mineralized zones, thus improving the odds of success for global gold exploration.  This objective will be achieved by studying the generation and composition of magmatic and metamorphic fluids in various Archean and Phanerozoic belts hosting orogenic gold deposits. The research will focus on investigating the fluids within (a) granites that were emplaced coevally with gold mineralization in the Val d'Or district, Canada, and (b) metamorphic rocks from the Otago-Alpine Schists, New Zealand, where there is a lack of magmatism. This research program will involve integrated field and laboratory investigations that are key to the training of highly qualified personnel for both academia and industry. The results are also expecting to lead to the development of novel techniques for analyzing single fluid inclusions and will be pioneering the direct identification of the trace-element composition  of metamorphic fluids in greenschist- and amphibolite-facies metamorphic rocks.