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

胶体传输在不列颠哥伦比亚省布鲁斯杰克高品位金矿形成中的作用

• 批准号: 467967-2014
• 负责人: Rowe, Christen
• 金额: $ 4.5万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=577171
• 关键词: Role; colloidal; transport; formation; grade

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.

金矿可以有多种形式。 金在存款中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，黄金在存款中的分布可能非常不规则（称为“块金”），难以估计。 这一困难延误了采矿许可，给资源开采带来了挑战。 我假设，一个根本的差异，金的运输和沉积的流体可能有助于解释存款风格之间的差异，并提供工具，了解黄金品位的结构控制。 Brucejack存款是这些情况之一，其中极高品位的静脉（高达>41公斤/吨）穿过贫瘠的围岩。 金的不规则分布和非常高的品位使我们假设金以固态纳米颗粒的形式在脉系统内运输。 由于成矿后的变形和变质作用，原生纳米颗粒已重结晶成较大的块金和薄片，运输和沉积的显微结构记录可能无法保存。 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迁移。 为了了解纳米颗粒运输在创造丰富的块状金矿床中的作用，我们将研究目前正在进行金富集的活跃热液系统中的蛋白石和石英脉矿床。 我们将描述金纳米颗粒形成并锁定在二氧化硅脉中时形成的微观纹理。 我们将把这些显微结构与布鲁斯杰克存款中保存的结构联系起来，并确定纳米颗粒浓度在创造丰富的金块金存款中起什么作用。 我们希望对构造的了解将有助于对这类资源的勘探和准确估计。