ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    黔西南泥堡金矿床含矿火山岩稀土元素地球化学特征

    REE Geochemical Features of Ore-hosted Volcanic Rocksin the Nibao Gold Deposit, Southwest Guizhou, China

    • 摘要: 泥堡金矿床含Au最高的容矿岩石是玄武安山岩,其Au品位含量高达32.5×10-6,稀土总量高达176.78×10-6~431.98×10-6,均值为237.4×10-6;轻重稀土比值为5.36~10.19,具有中基性岩浆岩稀土配分模式平缓右倾的典型特征。稀土总量高的样品均位于火山旋回的顶部,含Au最高的样品稀土总量也较高,金矿体的品位还与玄武安山岩的厚度略呈正比关系。按照岩浆上涌时同化混染规律,从早期至晚期,火山岩逐渐由基性向中基性演化,金与稀土元素逐渐富集,代表着火山旋回末次残余岩浆活动富集成矿特点。因而泥堡金成矿作用与峨眉山玄武岩残余岩浆相关,属于滇黔桂金成矿区内与火山作用相关的大型金矿床。

       

      Abstract: Basaltic andesite, as the highest gold content ore-hosted rock in the Nibao gold deposit, has highest gold grade of 32.5×10-6, and total rare earth elements (ΣREE) contents ranging from 176.78×10-6 to 431.98×10-6 with an average in 237.4×10-6. Their LREE/HREE ratios are 5.36~10.19, forming a figure gentle-dipped on the right side, according with the REE partition model of the intermediate-basic magma rock. The samples of highest ΣREE content are situated at the top of volcanic cycle, containing the highest gold grade ore. Furthermore, there is a roughly positive correlation between the gold grade of orebody and the thickness of basaltic andesite. According to the regulation of assimilation and contamination of upwelling magma, the medium-basic volcanic rocks were developed from basic rocks as the temporal order, while gold and REE were enriched gradually, which represent the residual magma enrichment and metallogenesis features of volcanic cycle. Therefore, the Nibao gold deposit is related to the residual magma eruption of Emeishan basalt, which is the large scale gold deposit related to the volcanism in Yunnan-Guizhou-Guangxi gold metallogenic province.

       

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