西昆仑新藏公路118～323km段基性、酸性岩脉K-Ar年龄

K-Ar ages of basic-acid dikes of the 118-323 km section of the Xinjiang-Tibet Highway in the West Kunlun

在西昆仑西段新藏公路沿线广泛发育数量众多的岩脉,野外出露有煌斑岩脉、辉绿岩脉、闪长岩脉、花岗岩脉。对以上岩脉进行了全岩K-Ar同位素测年,其侵位年龄与该区的地质构造事件有很好的对应关系:辉绿岩脉273～280Ma的侵位年龄对应着弧后扩张的时间,闪长岩脉和花岗岩脉230～244Ma的侵位年龄对应着碰撞造山的时间。

Many dikes occur along the Xinjiang-Tibet Highway in the western segment of the West Kunlun. Those exposed in the field are lamprophyre, diabase, diorite and granite dikes. Whole-rock K-Ar dating of these dikes indicates that their emplacement ages may well correspond with tectonic events in the study area. The 273-280 Ma age of emplacement of diabase dikes corresponds with the timing of back-arc spreading and the 230-244 Ma age of emplacement of diorite and granite dikes corresponds with the timing of collisional orogeny.