Role of colloidal transport in the formation of high grade gold veins at Brucejack, British Columbia

金矿可以有多种形式。金在矿床内的分布可能是相对系统的，在这种情况下，可以用最少的数据准确地估计资源。在其他情况下，金在矿床中的分布可能非常不规律(称为“块状”)，很难估计。这一困难延误了采矿许可，并给资源开采带来了挑战。我推测，金的运移和流体沉积方式的根本不同，可能有助于解释不同矿床类型的差异，并为理解构造对金品位的控制提供工具。 Brucejack矿床就是其中之一，在那里，极高品位的矿脉(高达41公斤/吨)切开贫瘠的围岩。金的不规则分布和非常高的品位使我们假设金是以纳米颗粒的形式在静脉系统内以固体状态运输的。由于矿化后的变形和变质作用，原生纳米颗粒被重新结晶成更大的块块和片状，可能不会保留迁移和沉积的微观结构记录。 在古老的和活跃的热液系统中都观察到了固体纳米颗粒的传输。为了了解纳米颗粒传输在创造丰富的、坚固的金矿中的作用，我们将研究来自活跃的热液系统的蛋白石和石英脉矿床，这些系统目前正在进行金的浓缩。我们将表征当金纳米颗粒形成并锁定在硅脉中时形成的微观纹理。我们将把这些微观结构与Brucejack矿床中保存下来的构造联系起来，并确定纳米颗粒浓度在创建丰富而坚固的金矿中所起的作用。我们希望结构性的理解将有助于对这类资源的勘探和准确估计。

Gold deposits can take many forms. The distribution of gold within a deposit may be relatively systematic, in which case it is possible to accurately estimate the resource with minimal data. In other cases, the distribution of gold in the deposit may be very irregular (known as "nuggety") and difficult to estimate. This difficulty delays mine permitting and creates challenges for resource extraction. I hypothesize that a fundamental difference in the way gold is transported and deposited by fluids may help explain the differences between deposit styles and provide tools for understanding the structural controls on gold grade. The Brucejack deposit is one of these cases, where extremely high grade veins (up to >41 kg/ton) cut through barren wall rock. The irregular distribution of gold and the very high grades lead us to hypothesize that the gold was transported within the vein system in the solid state as nanoparticles. Due to post-mineralization deformation and metamorphism, the primary nanoparticles have been recrystallized into larger nuggets and flakes, and the microstructural record of transport and deposition may not be preserved. Solid nanoparticle transport has been observed in both ancient and active hydrothermal systems. In order to understand the role of nanoparticle transport in creating rich, nuggety gold deposits, we will be studying opal and quartz vein deposits from active hydrothermal systems where gold enrichment is currently underway. We will characterize the microscopic textures which form when gold nanoparticles form and are locked up in silica veins. We will relate these microtextures to the preserved structures in the Brucejack deposit and determine what role nanoparticle concentration plays in creating a rich, nuggety gold deposit. We hope a structural understanding will contribute to exploration and accurate estimation of this type of resource.