建平地区早二叠世八家子超单元侵入岩及其侵入机制讨论

EARLY PERMIAN BAJIAZI ULTRA-UNIT INTRUSIVE ROCK FROM AND ITS EMPLACEMENT MECHANISM JIANPING AREA

建平八家子超单元花岗岩同位素年龄２７４．８～２６０Ｍａ（Ｕ／Ｐｈ，Ｋ／Ａｒ），属早二叠世．根据同源岩浆演化理论可划分为４个单元，即杨树岭单元、紫杖子单元、套卜河洛单元和太平庄单元，主要岩石为中细粒—巨粒似斑状二长花岗岩．由于侵位过程中的同构造变形作用，局部形成糜棱岩化花岗岩和片麻状花岗岩．岩浆侵位为膨胀底劈上侵．

The isotopic age of Bajiazi ultra-unit granite in Jianping area is 274. 8-260Ma(U/Ph.K/Ar),it belongs to Early Permain epoch. Based on the evolution theory of comagma, the rock body can be divided into 4 units: Yangshuling, Caizhangzi, Taobuheluo and Tai pingzhuang units. The major rock is medium-fine-giant grained porphyroid monzogranite.Owing to the syntectonic deformation during intrusion,there were mylonization granite and gneissic granite in part. The emplacement mechanism of its magma is dilatational diapiric uprising.