【摘要】 乌拉山地区大桦背花岗岩体和西沙德盖辉长闪长岩体位于华北地台北缘中段乌拉山地区,构造位置为阴山隆起中段,是研究古生代古亚洲洋板块与华北板块相互作用的重要区域。通过锆石LA-ICP-MS U-Pb定年、稀土和微量元素分析,获取了中细粒二长花岗岩、中粗粒二长花岗岩、中粗粒正长花岗和中细粒辉长闪长岩年龄,分别为(332. 8±1. 2)、(333. 8±1. 3)、(332. 6±1. 1)、(333. 2±1. 9) Ma,结果表明花岗岩和辉长闪长岩均属于早石炭世岩浆活动产物。大桦背花岗岩富硅、准铝-弱过铝质、高碱、相对富钾,属高钙碱性系列,轻稀土富集、重稀土亏损的右倾型配分模式,具高分异I型花岗岩特征,岩体边部广泛发育辉长闪长岩包裹体,花岗岩和辉长闪长岩稀土配分模式基本一致,各类数据表明这两个岩体在成因上具有密切联系。结合区域地质背景和构造图解分析,认为大桦背花岗岩体和辉长闪长岩体形成于古蒙古洋板块向华北古板块俯冲过程的弧后挤压向伸展环境过渡的活动大陆边缘地球动力条件下。更多还原

【Abstract】 The Dahuabei granite and the Xishadegai gabbro diorite are located in the Wulashan area in the middle of the northern margin of the North China craton and are located in the middle part of the Yinshan uplift. They are significant areas for the researching of the Paleozoic interaction between the paleo-Asia Ocean plate and the North China plate. According to the zircons LA-ICP-MS U-Pb dating,rare earth and trace element analysis,the age ofmedium-fine granodiorite,medium-coarse granodiorite,medium coarse granulite and medium fine grained diorite were( 332. 8 ± 1. 2),( 333. 8 ± 1. 3),( 332. 6 ± 1. 1),( 333. 2 ± 1. 9) Ma. The results show that both graniteand gabbro are belong to the Early Carboniferous magmatism. Dahuabei granite with rich silicon,quasi-aluminumweak permanganate,high alkali,relatively potassium-rich,is a high-calcium alkaline series,and belongs to light rare earth enrichmentfeatures,extensive palaeo-diorite inclusions in the margins of rock mass,and the patterns of REE are basically the same. All kinds of data show that the two rock masses are closely related in genesis. The gabbro inclusions are extensively developed in the margins of the rock mass,and the distribution patterns of rare earths are basically the same. All kinds of data show that the two rock masses are closely related in genesis. Based on the regional geological background and tectonic interpretation,it is concluded that the Dahuabei granite bodies and the gabbro bodies are formed during the arc-back extrusion to extensional environment during the subduction of the ancient Mongolian plate to the North China Plate.更多还原