Genesis of hydrothermal gold deposits

世界累计黄金产量的约20%来自太古代至整个显生宙形成的造山带金矿床。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知之甚少。关于流体的起源，人们提出了各种各样的模型，包括变质、地幔脱挥发、岩浆和大气。本研究计划提出(1)评价岩浆流体与变质流体在造山带金矿成因中的作用；(2)建立更精细的成因模型。这样的模型将有助于确定更多的潜在矿化带，从而提高全球金矿勘探成功的几率。这一目标将通过研究承载造山金矿床的各种太古宙和显生宙带的岩浆和变质流体的生成和组成来实现。研究将集中于调查(a)加拿大Val d'Or地区与金矿化同卵圆埋地的花岗岩和(b)新西兰奥塔哥-阿尔卑斯片岩的变质岩中的流体，那里缺乏岩浆活动。该研究项目将包括综合的实地和实验室调查，这对培养学术界和工业界的高素质人才至关重要。这些结果也有望导致分析单一流体包裹体的新技术的发展，并将开创直接识别绿片岩和角闪岩相变质岩中变质流体微量元素组成的先河。

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.