【摘要】 内蒙古商都县大石沟黑云母钾长花岗岩主要由钾长石（40～60%）、更长石（10～15%）、石英（25～32%）及黑云母（5～7%）组成。主元素SiO₂含量68.25%～69.64%,K₂O含量5.03%～8.03%,K₂O>Na₂O;A/CNK为0.77～1.1,稀土元素分馏较强,REE配分型式具中等铕负异常,岩石地球化学特征与碰撞花岗岩类似;本文对大石沟黑云母钾长花岗岩进行高精度锆石SHRIMP U-Pb定年研究。其形成时间为342±5Ma,可能代表华北板块与西伯利亚板块碰撞阶段的岩浆热事件。区域最新研究资料表明,侵入图林凯蛇绿岩带的埃达克岩的年龄为467～429Ma,代表洋壳俯冲的消减时间;390～310Ma花岗岩侵位的SHRIMP U-Pb锆石年龄以及383Ma蓝片岩Ar-Ar年龄代表华北板块与西伯利亚板块的碰撞事件;390～342Ma和324～310Ma花岗岩可能代表碰撞阶段两期岩浆热事件产物。更多还原

【Abstract】 The Dashigou biotite K-felspar granites consists mainly of orthoclase （40%～60%）,oligoclase （10%～15%）,quartz （25%～30%）and biotite（5%～7%）in the Shangdu county of Inner Mongolia.The biotite K-felspar granites are characterized with SiO₂（68.25%～69.64%）,K₂O（5.03%～8.03%）contents,K₂O>Na₂O and A/CNK=0.77～1.1,as will as fractionated REE patterns with middle negative Eu anomalies.The geochemical characteristics are similar to collision granites.Using High-precision SHRIMP U-Pb zircon dating method,We determine the Dashigou high-K granitoids were formed at 342±5Ma,the results indicate that the collision event of China plate with Xiboliya.took place in the Early Carboniferous epoch.Integrated with that the adakites, indicating the oceanic subduction event displaced at 467～429Ma from Tulinkai ophiolite zone.The 383Ma of glaucophane-schist Ar-Ar age from Sunitezuoqi region and 390Ma～310Ma SHRIMP U-Pb age of granites from the northern margin of the North China reflects that collision events between the North China and Xiberia Plates;390Ma～342Ma and 324Ma～310Ma of SHRIMP U-Pb zircon age of granitoids indicates two stage magmatism of the collision orogenic processes.更多还原