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中生代岩浆活动在太行山北段形成了一系列花岗岩体,其中的麻棚-赤瓦屋岩体侵位于穹窿状的阜平杂岩中,具有贫硅、富碱、高铝的钙碱性I型花岗岩特征。岩体分带明显,由边部向核部可以划分为石英闪长岩、花岗闪长岩、似斑状花岗岩3个相带,它们的锆石LA-ICP-MS U-Pb年龄分别为126.4±2.4 Ma、125.4±2.0 Ma和126.2±2.0 Ma,在误差范围内一致,指示岩体在早白垩世期间快速侵位、结晶。各相带样品的角闪石全铝平均值分别为1.018、0.880和0.871,对应的角闪石平均结晶压力分别为0.183、0.118和0.114 GPa,均值为0.141 GPa,对应的侵位深度约5 km,明显小于区域内元古界至侏罗系的地层厚度,表明在岩体侵位之前,阜平杂岩就已经具有穹窿状构造特征。结合相关资料,估计太行山早白垩世以来的平均隆升速率为0.07~0.08 km/Ma。
The Mesozoic magmatic activity formed a series of granitoids in the northern segment of the Taihang Mountains. The Mapeng-Chivawa intrusion is located in the dome-shaped Fuping complex with calc-alkaline I-type granite depleted in Si, Al and Al feature. The zonation of the rock body is obvious. From the edge to the core, it can be divided into three facies belts of quartz diorite, granodiorite and granite-like granite. Their LA-ICP-MS zircon U-Pb ages are 126.4 ± 2.4 Ma, 125.4 ± 2.0 Ma and 126.2 ± 2.0 Ma, which are consistent within the error range, indicating that the rock mass quickly invaded and crystallized during the Early Cretaceous. The average amphiboles of all phases are 1.018, 0.880 and 0.871, respectively, and the corresponding amphiboles are 0.183, 0.181 and 0.114 GPa, respectively, with an average of 0.141 GPa and corresponding emplacement depths of about 5 km , Which is obviously less than the thickness of the Proterozoic to Jurassic strata in the region, indicating that the Fuping complex had the dome-shaped structure before the intrusion of the rock mass. According to the related data, it is estimated that the average uplift rate of the Taihang Mountains since the Early Cretaceous is 0.07 ~ 0.08 km / Ma.