摘要
工作区位于西伯利亚板块南缘白音乌拉—东乌珠穆沁旗海西期岩浆岩带与滨太平洋构造域、大兴安岭燕山期岩浆岩带的叠加部位。结合岩石取样分析结果,对区内晚石炭世侵入岩地球化学特征及构造环境进行了探讨,结果表明:(1)晚石炭世早期以高钾钙碱性系列斑状二长花岗岩岩基侵入为主,该岩体具有钠高钾低、过铝质、稀土总量高等特点,后期中粒正长花岗岩侵入其中,规模不大;(2)晚石炭世中—晚期以碱长花岗岩侵入为主,最后以正长斑岩、石英正长斑岩等岩脉侵入活动为主,少量为花岗斑岩,该类岩脉位于白音图嘎一带,表现为大量密集的NW向脉岩群且多沿NW向张性断裂侵入,与断裂同期,其岩性组合为斑状二长花岗岩-正长花岗岩-碱长花岗岩-(石英)正长斑岩-花岗斑岩,具有由早期到晚期SiO_2含量逐步降低、稀土总量由低至高的演化特征;(3)整体上区内岩石地球化学特征显示为高钾钙碱性-钾玄岩系列火山岩,表明西伯利亚板块与华北板块已拼合,为碰撞后的伸展环境。
The working area is located in the superimposed part of Baiyinwula-Dong Ujimqin Banner Hercynian magmatic belt of the southern part of Siberian plate and Greater Khingan Mountains Yans- hanian magmatic belt of the shore of Pacific tectonic domain. Based on the analysis results of the rock samples ,the rock geochemical characteristics and tectonic environment of the Late Carboniferous intru- sions in Baiyintuga area are discussed, the results show that：①the early period of Late Carboniferous is mainly for the batholith intrusion of porphyritic monzonitie granite of high kalium calc alkaline series, the rock mass with the characteristics of high potassium and low sodium, peraluminous and high total rare earth, etc, in the late period, it is intruded by the medium grained syenite granite, but the intrusion scale is relatively small;②the medium-late period of Late Carboniferous Epoch is mainly for the granite intrusion, in the late period, it is mainly for dyke intrusion activities of syenite porphyry and quartz syenite porphy- ry, and secondary for the granite porphyry, the dikes are distributed in Baiyuntuga area, they are is charac- terized by a large number of intensive NW-direction vein rock groups, they intrusion activities of the vein rock groups are conducted along the NW-direction of the extensional fauhs,the vein rock groups with the same generation period of the fractures, the lithological combination of the vein rock groups porphyritic monzonitic granite-syenogranite-alkali-feldspar granite-（quartz） syenite porphyry - granite porphyry, with the evolution characteristics of gradually reduction of SiO2 contents and total rare earth changes from low to high from the late period to later period; ③overall speaking, the rock geochemical characteristics of Baiyintuga area show that the Late Carboniferous intrusions is belongs to the high potassium calc-alkaline- shoshonite series volcanic rocks,which show that the the Siberian plate and North China plate have been split, the tectonic environment of L
出处
《现代矿业》
CAS
2017年第3期1-8,25,共9页
Modern Mining
基金
中国地质调查局地质调查项目(编号:12120113072500)
关键词
侵入岩
地球化学特征
主量元素
微量元素
稀土元素
构造环境
Intrusions, Geochemical characteristics, Main elements, Trace elements, Rare earth ele-ments, Tectonic environment
