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依据仰宗岩体野外地质特征及主量元素地球化学特征分析表明,仰宗岩体岩性为流纹斑岩,岩石系列为高钾钙碱性过铝质系列。仰宗岩体A/CNK值为1.2～2.3,碱度率指数AR值为2.69～4.28,为S型花岗岩,仰宗岩体物质来源于地壳,属造山期花岗岩类型。仰宗岩体轻、重稀土的质量比为4.75～9.47,LaN/YbN>4,稀土分配型式为负铕的右倾海鸥式,微量元素地球化学相对富集Rb,Th,Ce和Sm(Sm富集不强烈),相对亏损Ta,Nb,Zr,Hf(Ba的贫化不强烈)。主量元素、稀土元素、微量元素地球化学综合分析表明,仰宗岩体形成于造山期后阶段的后碰撞应力松弛伸展环境。研究区砾石碎屑成分、二叠系地层沉积相变化、岩浆活动表明,从中二叠世早期或中期开始,哀牢山洋盆扩张已经停止,开始进入俯冲碰撞阶段。仰宗岩体侵入时间为263.1 Ma±2.3 Ma,表明,研究区内的哀牢山洋盆在中二叠世晚期可能已经碰撞闭合。
According to the geological characteristics of the Yangzong pluton and the geochemical characteristics of the major elements, it is shown that the lithology of the Yangzong pluton is rhyolite porphyry and the series of rocks are high-K calc-alkaline peraluminous series. The A / CNK of Yangzong pluton is 1.2 ~ 2.3, and the alkalinity index AR is 2.69 ~ 4.28, which is S-type granite. The Yangzong pluton is derived from the crust and belongs to the orogenic granite type. The mass ratios of light to heavy rare earths in Yangzong rock mass range from 4.75 to 9.47, with LaN / YbN> 4 and the right-leaning seagull with a negative Eu as the distribution pattern of REE. Trace elemental geochemistry is relatively enriched in Rb, Th, Ce and Sm Set is not strong), the relative loss of Ta, Nb, Zr, Hf (Ba depletion is not strong). Comprehensive analysis of major elements, rare earth elements and trace elements shows that the Yangzong pluton was formed in the post-orogenic post-orogenic stress relaxation and extension environment. In the study area, the composition of gravel debris and sedimentary facies in the Permian stratigraphy change. The magmatism indicates that from the early or middle Middle Permian, the expansion of the ocean basin in Ailaoshan has ceased and began to enter the subduction collision stage. The intrusion time of the Yangzong pluton was 263.1 Ma ± 2.3 Ma, indicating that the Ailaoshan Ocean basin in the study area may have collided and closed during the late Middle Permian.