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三丹汞矿带是我国重要的汞矿富集区,也是西南大面积低温成矿域的重要组成部分.为了阐明区内汞矿的成矿物质和成矿流体来源,作者对三丹汞矿带中段交犁-拉峨汞矿床中的方解石样品进行了REE和C-O同位素测试分析.结果显示方解石稀土总量(∑REE+Y=28×10~(-6)~70×10~(-6))相对较高,稀土配分模式为轻稀土(LREE)富集的右倾型(LREE/HREE=8.1~17),(La/Yb)_N为9.6~47,Y/Ho-La/Ho图解指示方解石为同源成矿流体的产物.Eu异常(δEu=0.75~3.6)变化较大,Ce异常不明显(δCe=0.86~0.98),整体呈弱正Eu异常和微弱负Ce异常,表明矿质发生沉淀时为弱氧化环境.通过与区内Au、Sb、Hg等低温矿床的C、H、Pb、S等同位素组成对比研究,认为拉峨汞矿床成矿物质来源于围岩,可能有沉积有机物质参与成矿.成矿流体以大气降水淋滤海相碳酸盐岩地层产生的壳源流体为主,不排除地幔流体参与成矿的可能性.
Sandan mercury deposit is an important mercury enrichment area in our country and an important part of large-scale low-temperature metallogenic area in Southwest China.In order to elucidate the source of metallogenic material and ore-forming fluid, REE and CO isotope analyzes of calcite samples from the Jiaozuo-Lhao mercury deposit in the middle section of the study show that the total amount of rare earth elements (ΣREE + Y = 28 × 10-6 ~ 70 × 10-6 (LREE / HREE = 8.1-17), (La / Yb) _N is 9.6-47, and the Y / Ho-La / Ho diagram indicates that the REE patterns are relatively high. The calcite is the product of a homogeneous ore-forming fluid, and the Eu anomalies (δEu = 0.75-3.6) vary greatly and the anomalies of Ce are insignificant (δCe = 0.86-0.98), showing weakly normal Eu anomaly and weakly negative Ce anomaly, When it is precipitated, it is a weak oxidation environment.Comparing with the isotopic compositions of C, H, Pb, S and other isotopes of low-temperature gold deposits such as Au, Sb and Hg in the area, it is concluded that the ore-forming materials of the La-Amalgam deposit originate from the surrounding rock and may have sedimentary organic Matter is involved in metallogenesis. The ore-forming fluid is dominated by shell-derived fluid produced by leaching leachate marine carbonate rock formation by atmospheric precipitation and does not exclude the possibility of mantle fluid being involved in metallogenesis.