石英微区分析和成矿模拟限定三道湾子富碲金矿床超常富集机理

Abundant epithermal gold deposits occur in the northern part of Heilongjiang province, among which the deposits featured by the tellurium-gold-silver combination in the Heihe area are the most important and characteristic. The contents of Te-Au-Ag minerals are usually more than 30% of all the gold-bearing minerals. However, the mechanism of unusual enrichment of tellurium-gold-silver during the epithermal mineralization in the region has not been well revealed. Hence, this study focuses on the quartz of different textures in each ore-forming stage at the Sandaowanzi large-scale high-grade tellurium-gold deposit in Heihe area. Based on the detailed fieldwork and microscopic observation, we use electron back scattering diffraction, cathodoluminescence, electron microprobe, laser ablation-inductively coupled plasma-mass spectrometry and secondary ion mass spectrometry situ microanalysis techniques to systematically analyze the changes of quartz textures, trace element migration and oxygen isotope fractionation. Meanwhile, we combine with calculations and simulations to better define the mechanism of unusual enrichment of tellurium-gold-silver, which can provide more evidences for understanding the ore genesis of epithermal tellurium-gold deposits and further exploration of regional potential resources.

黑龙江北部赋存大量浅成低温热液型金矿床，其中黑河地区以碲-金-银组合为特征的矿床最为重要也最具特色，典型矿床中Te-Au-Ag矿物通常占所有金矿物的30%以上。然而对区内浅成低温热液成矿过程中碲-金-银超常富集机理尚未得到很好的揭示。因此，本次申请以黑河地区三道湾子大型高品位碲金矿床不同成矿阶段和不同结构石英为研究对象，在详实的野外工作基础上，通过精细显微结构观察，应用背散射、阴极发光、电子探针、激光剥蚀电感耦合等离子质谱和离子探针等原位微区分析技术手段，系统剖析各成矿阶段石英结构变化、微量元素迁移和氧同位素分馏，结合计算、模拟，精细限定碲-金-银超常富集机理，为深化浅成低温热液高品位碲金矿床成矿理论认识和区域潜在资源的进一步勘探提供科学依据。

本项目以黑龙江北部的三道湾子大型高品位富碲金矿床载碲-金-银石英为研究对象，并对比了区域内同期贫碲的东安金矿床。采用先进的微区分析方法，开展大数据分析和地球化学计算、模拟，揭示了石英与碲-金-银富集的关系，精细限定了碲-金-银超常富集机制，并在热液矿石结构和石英化学成分方面进行了拓展。取得成果主要为：1）通过详细的矿石结构、高空间分辨率的氧同位素分析，结合平衡计算，限定了富碲和贫碲金银矿成因，深化浅成低温热液高品位碲金矿床成矿理论认识。2）通过石英缺陷机制、大数据和模拟计算，揭示了岩浆-热液系统石英微量元素的分布规律和影响因素，完善了石英微量元素基础理论。这些研究成果将为热液矿石石英微区分析和岩浆-热液系统石英微量元素研究提供重要的方法和理论支撑。研究同时指出将石英微量元素应用于岩浆-热液矿床的勘探具有重要潜力。