摘要:
罗容杂岩体主要由二长闪长岩、二长岩、二长正长岩和正长岩组成。岩石以富碱、富含Ba、K、Rb、Sr、Ga等大离子亲石元素(LILE)和LREE、Nb、Ta、Zr、HKTh、U、Y等高场强元素(HFSE)为主要特征,属钾玄岩系列。对罗容杂岩体进行了高精度的LA—ICP—MS锆石U-Pb定年,获得角闪辉石二长岩等时线年龄为163.40±0.40Ma(MswD=0.12)。研究认为罗容杂岩体形成于中侏罗世,属于A。亚型花岗岩,形成于燕山早期华南后造山阶段大陆地壳拉张减薄的构造环境。
Abstract:
Luorong magmatic complex is comprised of monzodiorite, monzonite, monzosyenite and syenite. These rocks are enriched in alkalies, large ion lithophile elements (such as Ba, K, Rb, Sr, Ga etc.), and high field strength elements (such as LREEs, Nb, Ta, Zr, Hf, Th, U, Y etc), belong to Shoshonitic series rocks. Zircon LA-ICP-MS U-Pb dating of hornblende augite monzonite yielded the isochron age of 163.40 _+ 0.40 Ma (MSWD=0.12), and indicated that Luorong magmatic complex was formed in Middle Jurassic Period and is belong to Al-subtype granite. The geochemical and geochronology data suggest that there intrusive bodies were emplaced at the post-orogenic state under an extensional and thinning environment within the South China continental crust.
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