The Shangqi area ofGreat Xing'an Range is tectonically located at the Xing'an Block in the eastern part of the Xingmeng oregenic belt.Large quantities of late Carboniferous granitic rocks are distributed in this area.Thesegranitic rocks are mainly composed of the quartz diorite and quartz monzodiorite.The LA-ICP-MS U-Pb zircon dating has yielded an age of (315.9±2.1) Ma,showing that the granite was mainly emplaced in late Carboniferousperiod.The petrogeochemical characteristics show that these granites are high-potassium,Si-saturated and quasi-aluminous rocks,belonging to calc-alkaline series.Discrimination diagrams show that the late Carboniferous granite belongs to Ⅰ-type granite.These graniteswere formed in a post-orogenic or post-collisional tectonic setting,whichrepresents an extensional tectonic environment.The petrography,petrogeochemistry,chronology study and regional tectonic evolution reveal that these late Carboniferous intrusions from Shangqi area in Great Xing'an Range were formed under a tectonic setting from late-orogenic to post-orogenic extension during the collision between Xing'an and Songnen Massifs.%大兴安岭上其尼克奇地区在构造上位于兴蒙造山带东段的兴安地块上,出露的晚石炭世花岗岩类主要由细粒石英闪长岩、石英二长闪长岩组成,岩石未遭变质作用.LA-ICP-MS锆石U-Pb测年结果为(315.9±2.1) Ma,为晚石炭世.岩石化学特征表明,研究区花岗岩均属于碱性岩,具有高钾、硅饱和、准铝质-弱铝质岩石的特征;依据系列判别图解显示研究区晚侏罗世花岗岩为高分异“Ⅰ”型花岗岩,岩浆的形成机制为壳幔同熔,形成于后造山或碰撞后的构造环境,代表了伸展的大地构造背景.岩相学、岩石地球化学、年代学研究以及区域构造演化表明,大兴安岭上其尼克其地区晚石炭世岩浆侵位活动可能发生在兴安地块和松嫩地块碰撞拼合所造成的造山晚期—造山后伸展构造背景下.
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