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浙西淳安大铜坑斑岩型钨钼矿位于扬子陆块东南缘,矿体主要产于花岗岩体与南华系休宁组变质砂岩内外接触带上,是揭示浙皖赣相邻区域成矿规律的重要组成.成矿花岗岩为高钾钙碱性系列准过铝质I型花岗岩,岩石富集Rb、K,亏损Sr、Ba等大离子亲石元素,富集Th、U,相对亏损Nb、Ta、Ti等高场强元素,稀土元素含量较低(ΣREE=106.2×10~(-6)~211.5×10~(-6)),轻重稀土分异明显(ΣLREE/ΣHREE=6.4~12.2),中等的Eu负异常(δEu=0.50~0.63),具有类似岛弧岩浆岩的特征.锆石SHRIMP U-Pb定年结果表明花岗岩侵位时间为148.3±1.9 Ma,辉钼矿Re-Os等时线年龄显示成矿作用发生于146.47±0.81Ma,成岩年龄与成矿时代高度耦合,进一步证实钨钼成矿作用与花岗岩体的形成有着密切的成因联系,二者在时间上是一个连续的过程,形成于晚侏罗世古太平洋板块俯冲挤压的构造环境,也是华南地区中生代第2次大规模钨钼成矿作用延续到浙西的响应.
The copper-molybdenum porphyry-type copper-copper deposits in Chun’an, western Zhejiang, are located in the southeastern margin of the Yangtze block. The ore bodies are mainly produced on the inner and outer contact zones between the granitic bodies and the Xiuning Formation metamorphic sandstones of the South China Sea, revealing the mineralization in the adjacent areas of Zhejiang, The ore-forming granite is a high-K calc-alkaline series of quasi-pervasive type I granites. The rocks are enriched in Rb and K, depleted in large ion lithophile elements such as Sr and Ba, enriched in Th and U, and relatively depleted in Nb (ΣREE = 106.2 × 10 -6 ~ 211.5 × 10 -6)), and the variation of light and heavy rare earth is obvious (ΣLREE / ΣHREE = 6.4 ~ 12.2 ) And moderate Eu negative anomalies (δEu = 0.50-0.63), which are similar to the island arc magmatic rocks.The results of SHRIMP U-Pb zircon dating show that the emplacement time of granite is 148.3 ± 1.9 Ma, that of molybdenite Re-Os The time-line age shows that mineralization took place at 146.47 ± 0.81Ma, and the age of diagenesis was highly coupled with the metallogenic epoch, further confirming that tungsten and molybdenum mineralization are closely related to the formation of granite, both of which are continuous in time Process, formed in the tectonic setting of the subduction of the Paleo-Pacific plate in the Late Jurassic and also the second large-scale Tungsten and Molybdenum Mine action continues to respond to the west of Zhejiang.