湖南锡田和邓阜仙燕山期花岗岩的源区差异及其意义

发布时间：2018-04-18 19:50

  本文选题：燕山期花岗岩 + 源区　； 参考：《中南大学学报(自然科学版)》2017年01期

【摘要】：对湖南茶陵锡田和邓阜仙复式岩体燕山期二云母花岗岩进行岩相学、锆石及岩石元素地球化学特征的对比研究,以探讨其源区可能的差异对钨锡多金属成矿的影响。研究结果表明:锡田与邓阜仙二云母花岗岩均显示为高硅、高铝、富碱特征,较高的10 000w(Ga)/w(Al)(分别为3.58~4.20和2.04~4.11,w为质量分数)指示其为A型花岗岩;w(Nd)/w(Th)15和w(Th)/w(U)1特征指示两者为壳源,但锡田岩体较邓阜仙岩体含磷低,更富稀土元素,其Eu负异常(δ(Eu)=0.03~0.04)较邓阜仙岩体(δ(Eu)=0.24~0.85)更显著,轻重稀土分馏程度更低,其稀土配分曲线呈"对称"型,而邓阜仙岩体为"右倾"型;由锆石组分计算的锡田与邓阜仙岩浆结晶温度分别为823~945℃和613~922℃,氧逸度lg(fo_2/10~5 Pa)分别为-14.7和-16.8,表明两岩体均为形成伸展背景下的A型花岗岩,是元古宙地壳部分熔融产物;源区以碎屑岩为主,锡田岩体源区应更富火成岩,这表明同为壳源,且同期、空间相邻岩体仍可存在源区和成岩环境的差异,这种物源背景差异对成矿产生影响。
[Abstract]:The petrographic, zircon and element geochemical characteristics of the Yanshanian metamorphic granites of the Chaling Xitian and Dengfu Xianshen complex intrusions were studied in order to explore the influence of the possible source regions on the mineralization of tungsten and tin polymetallic deposits.The results show that both Xitian and Dengfu Xiandimica granites are characterized by high silicon, high aluminum and rich alkali. The higher 10000w / w Gaan / w / w (3.58 ~ 4.20 and 2.044 ~ 4.11w mass fractions respectively) indicate that they are A-type granitoids and w(Th)/w(U)1 characteristics indicate that they are crusts, and the characteristics of w(Th)/w(U)1 indicate that they are crust source, and the results show that the two types of granites are high in silicon, high in aluminum and rich in alkali-rich elements.However, the Xitian rock body has lower phosphorus content and more rare earth elements than the Dengfuxian rock mass. The EU negative anomaly (未 ~ (2 +) EU (0.03) 0.04) is more significant than that of the Dengfu Xianshan rock mass (未 ~ (2 +) EU ~ (2 +) 0.240.85), and the fractionation degree of heavy and heavy rare earth elements is lower, and the REE distribution curve is "symmetrical" type, while the "right dip" type of the Dengfu Xianshan rock mass.The crystallization temperatures of Xitian magma and Dengfuxian magma calculated from zircon composition are 823 ~ 945 鈩，

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