In many orogenic gold deposits, gold is located in quartz veins. Understanding vein development at the microstructural scale may therefore provide insights into processes influencing the distribution of gold, its morphology, and its relationship to faulting. We present evidence that deformation processes during aseismic periods produce characteristic quartz microstructures and crystallographic preferred orientations, which are observed across multiple deposits and orogenic events. Quartz veins comprise a matrix of coarse, subidiomorphic, and columnar grains overprinted by finer-grained quartz seams subparallel to the fault trace, which suggests an initial stage of cataclastic deformation. The fine-grained quartz domains are characterized by well-oriented quartz c-axis clusters and girdles oriented parallel to the maximum extension direction, which reveals that fluid-enhanced pressure solution occurred subsequent to grain refinement. Coarser anhedral gold is associated with primary quartz, whereas fine-grained, “dusty” gold trails are found within the fine-grained quartz seams, revealing a link between aseismic deformation and gold morphology. These distinct quartz and gold morphologies, observed at both micro- and macroscale, suggest that both seismic fault-valving and aseismic deformation processes are both important controls on gold distribution.

中文翻译：

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抗震期间造山带金系统的变形机制：来自澳大利亚东南部维多利亚中部金矿床的微观结构证据

在许多造山带金矿床中，金位于石英脉中。因此，了解微观结构尺度上的矿脉发育可能有助于深入了解影响金分布、形态及其与断层关系的过程。我们提供的证据表明，在抗震期间的变形过程会产生特征性的石英微结构和晶体择优取向，这在多个沉积物和造山事件中观察到。石英脉由粗糙的、亚自形的和柱状晶粒组成，上面覆盖着与断层轨迹平行的细粒石英接缝，这表明处于碎裂变形的初始阶段。细粒石英域的特征是定向良好的石英 c 轴簇和平行于最大延伸方向的环带，这表明在晶粒细化之后发生了流体增强的压力溶解。较粗的反面体金与原生石英有关，而细粒的、“尘土飞扬的”金痕迹则在细粒石英接缝中发现，揭示了抗震变形与金形态之间的联系。在微观和宏观尺度上观察到的这些不同的石英和金形态表明，地震断层阀和抗震变形过程都是金分布的重要控制因素。