The Augmitto-Bouzan deposit is a 12 km long segment of the Larder Lake-Cadillac Deformation Zone (LLCDz) south of Rouyn-Noranda (Québec, Canada) that is characterized by an uneven gold distribution hosted in quartz-carbonate ± tourmaline veins within Piché Group ultramafic rocks. This study compares the fluid flow conditions between the variable gold-endowed sectors to identify deposit-scale processes responsible for gold endowment. Stable isotopes indicate that quartz and tourmaline have equilibrium temperatures (228–⁠420 °C) that likely define a high vertical thermal gradient (~ 30 °C/100 m) along the LLCDz. Covariation between temperature and computed δ¹⁸O_H2O and δD_H2O is interpreted to result from mixing between a high temperature (> 420 °C), high δ¹⁸O (> 10.8‰), and low δD (< –29‰) deep-seated metamorphic fluid, and a low temperature (< 230 °C), low δ¹⁸O (< 4‰) and high δD (~ 0‰) upper crustal pore fluid. Local upwelling of auriferous deep-seated fluid, shown by interpolation of δ¹⁸O_H2O in the gold-endowed Augmitto-Cinderella and Astoria segments, was likely focused along higher permeability deformation-related pathways. Sectors of low gold endowment have lower δ¹⁸O_H2O and fluid/rock ratios, likely reflecting a larger proportion of upper crustal fluid and differences in fluid-flow behavior. Modeling of fluid flow shows that this is due to 1) weaker metamorphic fluid flux in the thinner band of Piché Group rocks and 2) more porous volcanic rocks north of the LLCDz, drawing more pore fluid into the fault. We suggest that most of the variation of gold endowment is related to variations in advection of auriferous metamorphic fluid along the segment, whereby a weaker metamorphic fluid flux or increased admixture of upper crustal fluids decrease the gold potential along the LLCDz.

Augmitto-Bouzan 矿床是鲁安-诺兰达（加拿大魁北克省）以南拉德湖-凯迪拉克变形带 (LLCDz) 的一段 12 公里长的区域，其特征是金分布不均匀，分布在皮谢内的石英碳酸盐 ± 电气石矿脉中群超镁铁质岩石。本研究比较了可变黄金赋存部门之间的流体流动条件，以确定导致黄金赋存的矿床规模过程。稳定同位素表明石英和电气石具有平衡温度 (228–⁠420 °C)，这可能定义了沿 LLCDz 的高垂直热梯度 (~ 30 °C/100 m)。温度与计算出的 δ ¹⁸ O _H2O和 δD _H2O之间的协变被解释为高温 (> 420 °C)、高 δ ¹⁸ O (> 10.8‰) 和低 δD (< –29‰) 之间混合的结果）深层变质流体，以及低温（< 230 °C）、低δ ¹⁸ O（< 4‰）和高δD（~ 0‰）上地壳孔隙流体。通过在金矿赋存的 Augmitto-Cinderella 和 Astoria 段中插值 δ ¹⁸ O _H2O显示，含金深部流体的局部上升可能集中在较高渗透率的变形相关路径上。含金量低的区域具有较低的 δ ¹⁸ O _H2O和流体/岩石比，可能反映了上地壳流体的比例较大以及流体流动行为的差异。流体流动模型表明，这是由于 1) Piché 群岩石较薄带内的变质流体通量较弱，2) LLCDz 北部的多孔火山岩较多，将更多的孔隙流体吸入断层中。 我们认为，金矿赋存量的大部分变化与沿该段的含金变质流体平流变化有关，因此变质流体通量较弱或上地壳流体混合物增加会降低LLCDz沿线的金矿潜力。