中文摘要：

本文对内蒙古达茂旗北部的岛弧侵入岩进行了精确的SHRIMP锆石U-Pb定年研究和地球化学研究。该侵入岩具有正常岛弧和埃达克岩的双重地球化学性质。SHRIMP锆石U-Pb定年表明,这套侵入岩中的闪长岩形成于452±3Ma和440±2Ma,石英闪长岩形成于446±2Ma,花岗闪长岩形成于440±2Ma,它们记录了晚奥陶纪末的洋壳消减事件。在一个细粒闪长岩中,分辩出了1967±13Ma（n=3）的继承性锆石,指示这一岛弧可能具有一个前寒武纪的大陆基底。

英文摘要：

We provide new geochronological and geochemical constraints on the formation and evolution of an early to mid-Paleozoic arc pluton, from north of Damaoqi, Inner Mongolia. This pluton has a transitional normal arc/adakite geochemical affinity. SHRIMP zircon U-Pb ages suggest that diorites was emplaced at 452±3 Ma and 440±2 Ma, quartz diorite at 446±2 Ma, and granodiorite at 440±2 Ma, which represents an Ordovician oceanic subduction event. Precambrian zircon inheritance （ca. 1967 Ma） occurs in a finegrained diorite which indicates that the arc was built on a Precambrian continental crust.