摘要:
黄峰寨岩体位于南岭钨锡多金属成矿带的东段,对该岩体中的石英二长岩进行 SHRIM P 锆石 U‐Pb 年龄测定、岩石学和地球化学研究。石英二长岩的 SHRIMP 锆石 U‐Pb 年龄为231±3 Ma ,属中三叠世晚期。岩石学和地球化学特征表明,该岩体具有高硅、富铝、高钾、中碱、高钙的特征,属高钾钙碱性系列弱过铝质 S 型花岗岩类;微量元素 Sr 、Ba 、Nb 、P 、Ti 强烈亏损,Rb 、Th 、Ce 、Zr 、Sm 相对富集;稀土元素总量高,轻稀土富集,轻、重稀土分异明显,Eu 中等负异常;Hf(t)为-15.25~-2.88,Hf 两阶段模式年龄值为1.87~2.22Ga ,表明黄峰寨岩体为上地壳底部基性岩部分熔融的产物,推测该岩体可能形成于同碰撞构造环境。
Abstract:
The Huangfengzhai pluton is located in the eastern section of tungsten‐tin polymetallic met‐allogenic belt in the Nanling region .This study carried out SHRIM P zircon U‐Pb dating and lithological and geochemical anlyzses for quartz monazites from the Huangfengzhai pluton .The results show that a zircon U‐Pb age of quartz monzonite from the Huangfengzhai pluton is 231 ± 3 Ma ,belonging to late Mid‐dle Triassic .Lithological ,mineralogical and geochemical analyses suggest that the pluton is rich in Si ,Al and Ca ,with medium alkali ,indicating that the pluton belongs to high‐K ,calc‐alkaline series ,weakly‐per‐luminous S‐type granitoids .The pluton is also depleted in Sr ,Ba ,Nb ,P and Ti ,but relatively enriched in Rb ,Th ,Ce ,Zr and Sm ,with high ΣREE content ,distinct LREE and HREE differentiation ,and weak negative Eu anomalies .Zircon εHf(t) values range from - 15 .25 to - 2 .88 and Hf two‐stage model age values are 1 .87 ~ 2 .22 Ga ,indicating that the Huangfengzhai pluton was derived from partial melting of mafic rocks at the bottom of upper crust .It can be inferred that the Huangfengzhai pluton might form at a syncollosion tectonic setting .
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