北京云蒙山花岗岩基的岩石变形及其成因

Rock Deformation and Genesis of Yunmengshan Granitic Batholith

云蒙山花岗岩基由12个侵入体组成,岩基中的片麻状花岗岩是在126±21Ma时侵入的Ⅰ型花岗岩。根据岩基中花岗岩与围岩的变形特征,确定岩基的侵位机制为底辟定位型。花岗岩中的变形组构与环绕岩基的糜棱岩带在岩基定位晚期、花岗岩浆完全结晶之前形成。由于云蒙山花岗岩基的强力定位,导致密怀变质核杂岩在燕山晚期再次发生伸展构造运动。

Yunmengshan granitic batholith consists of 12 intrusive bodies. The foliated granites in the batholith are I-type granite which intruded at 126 (±21)Ma. It is considered that theemplacement mtchanism of batholith is diapir penetration according to the deformational features of the granites and country rocks. The deformational structure and mylonite zone around the batholith are thought to form in the late period of emplacement for the granitic batholith before the granitic magma completely crystallized. The extension of Mihuan metamorphic core complex in the late stage of Yanshan movemont resulted from the powerful emplacement of the Yunmengshan batholith.