内蒙古苏尼特左旗晚石炭世花岗岩地球化学特征及其意义

Late Carboniferous Granite Geochemical Features and Its Significance in Sonid Left Banner,Inner Mongolia

内蒙古苏尼特左旗晚石炭世花岗岩位于兴蒙造山带中的二连—贺根山断裂带南侧,属中亚造山带的一部分,研究该花岗岩能够对兴蒙造山带晚古生代构造演化提供新的证据。该地区的粗中粒花岗闪长岩为一套高钾钙碱性花岗岩,岩浆经历了较彻底的分异演化,分离结晶程度高。LREE轻度富集,HREE轻度亏损,具中等程度的Eu负异常。岩浆岩成因类型为Ⅰ型花岗岩,为破坏性活动板块边缘(板块碰撞前)花岗岩,指示西伯利亚板块和华北板块在研究区于(晚)石炭世开始碰撞。

The late Carboniferous granite in the Sonid Left Banner,Inner Mongolia is situated on the south side of the Erenhot-Hogenula fault,Hinggan-Mongolian orogenic belt,a part of Middle Asian orogenic belt.The study of the granite can provide new evidence for Hinggan-Mongolian orogenic belt late Paleozoic tectonic evolution.The coarse-medium grained granodiorite in the area is a set of high-K calc-alkaline granite;the magma has experienced rather thorough differential evolution,with high degree of separation and crystallization.The LREE is lightly enriched,HREE lightly deficient,with medium degree Eu negative anomaly.Magmatic rock genetic type is type I granite,destructive active plate margin(before plate collision)granite,thus indicated the collision of the Siberian plate and North China plate has started from Late Carboniferous Epoch.