In response to the craton destruction, the North China Craton (NCC) underwent the Early Cretaceous extensional tectonics. During this period, the eastern NCC has also experienced numerous plutonism, volcanism, and extensional structures. Particularly, half-graben or graben, Early Cretaceous extensional domes, metamorphic core complex, and syn-kinematic plutons are widespread throughout the NCC and its surrounding area, with a peaking age of 125 Ma, pointing to a large-scale severe NW-SE extension. However, it remains unknown when and how the large-scale extension is initiated. To answer this key issue, we choose two plutons (Fengjiayu-Xibailianyu and Gubeikou plutons) with the age of early stage of the Early Cretaceous (130–127 Ma) as the target of this study. The Fengjiayu-Xibailianyu pluton is close to, while the Gubeikou pluton is far away from the Early Cretaceous intensive extensional region. A multidisciplinary study, including structural geology, anisotropy of magnetic susceptibility (AMS), and gravity modeling, has been carried out on these two plutons to reveal the tectonic regime coeval with their emplacement. Both of these two plutons share similar features of concentric magnetic foliations and variable magnetic lineations which are decoupled with the ductile fabric in their country rocks. Accordingly, we considered that they intruded in a permissive way at a weak extension regime during the Early Cretaceous (130–127 Ma), just before the Late Mesozoic peak of the magma flare-up and large-scale extensional tectonics of the NCC. Combined with our previous works, the Early Cretaceous NW-SE trending extension in NCC was further subdivided into the early-stage weak extension during 130–127 Ma and the late-stage intensive extension during 127–110 Ma, namely the large-scale extension initiated after 127 Ma. The early-stage extension could be ascribed to the westward subduction of the Izanagi plate under the Eurasian continent.

为应对克拉通的破坏，华北克拉通（NCC）经历了早白垩世的伸展构造。在此期间，华北克拉通东部也经历了多次深成作用、火山作用和伸展构造。特别是半地堑或地堑、早白垩世伸展圆顶、变质核心杂岩和同运动岩体广泛分布于华北克拉通及其周边地区，峰值年龄为 125 Ma，指向大规模的严重 NW-SE 延伸。但是，尚不清楚何时以及如何启动大规模扩展。为回答这一关键问题，我们选取​​了早白垩世早期（130~127 Ma）的两个岩体（冯家峪-西白莲峪和古北口岩体）作为研究对象。冯家峪-西白莲峪岩体靠近，古北口岩体远离早白垩世密集伸展区。对这两个岩体进行了包括构造地质学、磁化率各向异性（AMS）和重力模拟在内的多学科研究，以揭示与其就位同时发生的构造机制。这两个岩体具有相似的同心磁层理和可变磁理线特征，这些特征与它们的围岩中的韧性结构脱钩。因此，我们认为它们在早白垩世（130-127 Ma）的弱伸展状态下以允许的方式侵入，就在晚中生代岩浆爆发和华北克拉通大规模伸展构造之前。结合前期工作，华北克拉通区早白垩世NW-SE走向延伸进一步细分为130~127 Ma早期弱延伸和127~110 Ma晚期强化延伸，即大规模延伸127 Ma 后开始。早期的伸展可以归因于伊邪那岐板块向欧亚大陆的西俯。