共沉淀
胶体金
地质学
无定形二氧化硅
无定形固体
金矿石
地球化学
纳米颗粒
材料科学
化学工程
纳米技术
结晶学
化学
工程类
作者
Rory R. McNab,Joël Brugger,Christopher R. Voisey,Andrew G. Tomkins
出处
期刊:Geology
[Geological Society of America]
日期:2024-07-09
摘要
Hyperenrichment of Au in orogenic ores occurs overwhelmingly within quartz veins, but the formation pathway of quartz veins in orogenic systems remains enigmatic. We conducted hydrothermal experiments simulating coprecipitation of Au and amorphous silica and subsequent recrystallization to test whether this is a viable mechanism to generate Au nuggets within quartz veins. Within minutes, coprecipitation of amorphous silica and Au nanoparticles occurred, representing an effective Au deposition mechanism. Within one week, amorphous silica had recrystallized to quartz, causing the coarsening of Au particles and their relocation to quartz grain boundaries and fractures. The experimental textures are similar to those observed in high-grade zones of orogenic gold deposits. In addition to trapping Au, amorphous silica may increase competency contrasts that facilitate short-term fracture reactivation during earthquake aftershock periods or swarms, allowing further Au input from fresh fluids. These findings demonstrate that amorphous silica precipitation may be an important transient stage in orogenic gold deposit formation, with significant implications for metal accumulation in quartz veins.
科研通智能强力驱动
Strongly Powered by AbleSci AI