论文部分内容阅读
仙人岩岩体位于湖南水口山矿田的南部。岩体内外接触带上均见有不同程度的金、铜、钼、锌等矿化,反映出岩体与成矿存在着内在联系。二长岩中锆石的LA-MC-ICP-MS年代学研究表明,其U-Pb加权平均年龄值为(156.09±0.46)Ma(MSWD=1.4),显示为燕山早期侵位。锆石Lu-Hf同位素原位分析结果表明,176 Hf/177 Hf值为0.282 243～0.282 904,εHf(t)值为-15.55～7.87,峰值在-10左右,Hf同位素二阶段模式年龄(TDM2)为703～2 188Ma,峰值在1 800Ma左右,指示岩浆为壳幔混合来源。结合岩体的地球化学特征,认为仙人岩岩体主要来源于中元古代基底的重熔,是在中晚侏罗世地壳拉张减薄构造背景下形成的。另外,对比分析了仙人岩岩体与水口山岩体的的岩石地球化学特征,前者分异演化程度相对较弱,这可能是其不利于形成同类矿床的原因。
The immortal rock body is located in the south of Moutou Mountain in Hunan Province. There are different levels of gold, copper, molybdenum, zinc and other mineralization on the inner and outer contact zones of rock mass, reflecting the inherent relationship between rock mass and mineralization. The LA-MC-ICP-MS chronology of zircons in the monzonite shows that the U-Pb weighted average age value is (156.09 ± 0.46) Ma (MSWD = 1.4), indicating early emplacement of the Yanshan. The results of in-situ zircon Lu-Hf isotopic analysis show that the 176 Hf / 177 Hf values are 0.282 243-0.282904, the εHf (t) values are -15.55-7.87, the peak values are around -10, and the Hf isotope two- ) Is 703 ~ 2 188Ma, the peak value is about 1800Ma, indicating that the magma is a crust-mantle mixed source. Based on the geochemical characteristics of the rock mass, it is believed that the cinnabar rock mass mainly comes from the remelting of the Mesoproterozoic basement formed under the tectonic extension of the mid-late Jurassic crustal pull-thinning. In addition, the geochemical characteristics of the rocks of the Xianrenite and Shuikoushan are comparatively analyzed. The former is relatively weakly differentiated, which may be the reason that it is not conducive to the formation of similar deposits.