CAJ | 학술논문

大地构造位置隶属乌里雅思太活动大陆边缘的内蒙古东乌旗地区，是中亚造山带的重要组成部分，其内发育有大量的岩浆岩，侵入岩时代以二叠纪及晚中生代为主，鲜有早期岩体的报道。对该区莫合尔图一带的闪长岩进行锆石LA-MC-ICP-MS U-Pb同位素测定，结果显示，24个测点的年龄值比较集中，加权平均值为（337.1±1.9）Ma（MSWD＝1.3），所测锆石具岩浆锆石的特征，表明岩体应形成于石炭纪。结合区域地质资料，认为东乌旗地区可能存在时限为337～310 Ma的构造-热事件。
대지구조위치대속오리아사태활동대륙변연적내몽고동오기지구，시중아조산대적중요조성부분，기내발육유대량적암장암，침입암시대이이첩기급만중생대위주，선유조기암체적보도。대해구막합이도일대적섬장암진행고석LA-MC-ICP-MS U-Pb동위소측정，결과현시，24개측점적년령치비교집중，가권평균치위（337.1±1.9）Ma（MSWD＝1.3），소측고석구암장고석적특정，표명암체응형성우석탄기。결합구역지질자료，인위동오기지구가능존재시한위337～310 Ma적구조-열사건。
Dongwuqi area in Inner Mongolia,which lies in Uliastai active continental margin,is a part of Cen-tral Asian orogenic belt.Numerous magmatites are exposed in this area.The intrusive rocks mainly formed in Permian and Late Mesozoic,and seldom formed in the other period according to report.Diorite was discovered in Moheertu of this area during the 1∶50,000 regional geological surveys.By LA-MC-ICP-MS U-Pb isotopic dating for 24 zircons,weighted mean age of (337.1 ±1.9)Ma (MSWD=1.3)was obtained from the diorite. The characteristics of these zircons accord with magmatic zircon,and the results can represent the diagenetic age of diorite.Combined with regional geology,we concluded that a tectono-thermal event occurred during 337 -310 Ma in Dongwuqi area.