A suite of Jurassic–Cretaceous migmatites was newly identified in the Liaodong Peninsula of the eastern North China Craton (NCC). Anatexis is commonly associated with crustal thickening. However, the newly identified migmatites were formed during strong lithospheric thinning accompanied by voluminous magmatism and intense deformation. Field investigations show that the migmatites are spatially associated with low-angle detachment faults. Numerous leucosomes occur either as isolated lenses or thin layers (dykes), parallel to or cross-cutting the foliation. Peritectic minerals such as titanite and sillimanite are distributed mainly along the boundaries of reactant minerals or are accumulated along the foliation. Most zircons show distinct core–rim structures, and the rims have low Th/U ratios (0.01–0.24). Zircon U–Pb dating results indicate that the protoliths of the migmatites were either the Late Triassic (224–221 Ma) diorites or metasedimentary rocks deposited sometime after c. 1857 Ma. The zircon overgrowth rims record crystallization ages of 173–161 Ma and 125 Ma, which represent the formation time of leucosomes. These ages are consistent with those reported magmatic events in the Liaodong Peninsula and surrounding areas. The leucosomes indicate a strong anatectic event during the Jurassic–Cretaceous period. Partial melting occurred through the breakdown of muscovite and biotite with the presence of water-rich fluid under a thermal anomaly regime. The possible mechanism that caused the 173–161 Ma and 125 Ma anatectic events was intimately related to the regional crustal extension during the lithospheric thinning of the NCC. Meanwhile, the newly generated melts further weakened the rigidity of the crust and enhanced the extension.

中文翻译：

---

辽东半岛新发现侏罗系-白垩系混合岩：揭示与华北克拉通岩石圈减薄有关的中生代深熔事件

在华北克拉通东部（NCC）辽东半岛新发现一套侏罗系-白垩系混合岩。Anatexis 通常与地壳增厚有关。然而，新发现的混合岩是在强烈的岩石圈减薄过程中形成的，伴随着大量的岩浆作用和强烈的变形。实地调查表明，混合岩在空间上与低角度拆离断层有关。许多白质体以孤立的晶状体或薄层（堤）的形式出现，平行于或横切叶面。包晶矿物如榍石、硅线石主要沿反应物矿物边界分布或沿叶理堆积。大多数锆石显示出明显的核心-边缘结构，并且边缘具有低 Th/U 比（0.01-0.24）。C。1857 马。锆石过度生长边缘记录的结晶年龄为 173-161 Ma 和 125 Ma，这代表了 leucosomes 的形成时间。这些年龄与所报道的辽东半岛及周边地区的岩浆事件一致。淡色体表明侏罗纪-白垩纪期间发生了强烈的深熔事件。在热异常状态下，随着富水流体的存在，白云母和黑云母的分解发生了部分熔融。造成173~161 Ma和125 Ma深海事件的可能机制与NCC岩石圈减薄过程中的区域地壳伸展密切相关。同时，新生成的熔体进一步削弱了地壳的刚性，增强了延展性。