内蒙古阿巴嘎旗北部侵入岩体地质地球化学特征及成因

Geological and geochemical characteristics and petrogenesis of intrusive bodies in northern Abagaqi,Inner Mongolia

内蒙古阿巴嘎旗北部位于西伯利亚板块东南大陆边缘晚古生代陆缘增生带,地处二连—贺根山板块对接带的西北侧.通过对三类侵入岩体样品主微量元素地球化学特征的分析,结果显示正长花岗岩体(包括中细粒正长花岗岩、条纹正长花岗岩、钠长正长花岗岩)和碱长花岗岩体(中粗粒钠闪正长花岗岩、钠闪条纹正长花岗岩)都具有A型花岗岩的特征,碎裂岩化花岗斑岩岩体兼具A型和S型花岗岩的特征.三类侵入岩体岩浆成因与陆壳变杂砂岩部分熔融有关,均产于后造山构造环境.

The northern Abagaqi is located in the northwest of the suture belt between Erlian and Hegenshan Plate, which is a part of the accretion zone of the late paleozoic continental margin on the southeast continental margin of the Siberian Plate. Sampling of three rock types of the northern Abagaqi was conducted to analyze the content of major and trace elements, and the results showed that syenite granite mass （including the fine- grained syenite granite, stripe syenite granite, albite syenogranite） and alkali feldspar granite mass（including coarse-grained riebeckite syenite granite, riebeckite stripe syenogranite） have the characteristics of the A-type granite, granite porphyry mass of both A and S-type granites. The magmatic origin of the three types of intrusive bodies has a relationship with metagreywacke patiral melting of the continental crust, which was produced in the post-orogenic tectonic environment.