内蒙古扎兰屯西部早白垩世二长花岗岩岩石地球化学特征及成因探讨

Discussion on Geochemical Characteristics and Causes of Early Cretaceous Epoch Monzogranite in the West of Zhalantun,Inner Mongolia

内蒙古扎兰屯西部地区的早白垩世二长花岗岩,总体呈条带状近东西向和南北向展布。岩石类型以二长花岗岩为主,其岩石地球化学特征反映出本期花岗岩具有高钾钙碱性、过铝质特点,富集大离子亲石元素(LILE)和轻稀土元素(LREE),相对亏损高场强元素(HFSE)。在R1-R2构造环境判别图解中,投影点落入后造山期的花岗岩区。在微量元素Y-(Yb+Nb)图解中,岩石投影点落入火山弧花岗岩区。这说明本期花岗岩形成于后造山阶段。

The early cretaceousepoch monzogranite in the western area of Zhalantun,Inner Mongolia has the long strip towards nearly east-west and north-south direction.The rock type is mainly fine-medium monzogranite,The rock geochemical characteristics further reflects that the granite has the characteristics of high potassium calcium base and peraluminous,full of LILE and LREE,relatively loss HFSE.In the R1-R2 tectonic environment discrimination diagram,the subpoint falls in the granite zone of the post-orogenic.In the microelement Y-(Yb+Nb)diagram,the subpoint falls in volvanic arc granite.This reflects the granite formed in the post-orogenic.