Mass alkaline magmatic activities in Western Shandong during the late Mesozoic controlled the mineralization processes of gold and rare earth element (REE) polymetallic deposits in the region. The Chishan alkaline complex is closely associated with the mineralization of the Chishan REE deposit, which, as the third largest light REE deposit in China following the Baiyenebo (Inner Mongolia) and Mianning (Sichuan) deposits, is considered a typical example of alkaline rock mineralization throughout the North China Craton. To determine how the Chishan alkaline complex and REE deposit interact with each other, a systematic study was conducted on the petrology, rock geochemistry, zircon U–Pb geochronology, Lu–Hf isotopes of the quartz syenite, and alkali granite contained in the Chishan alkaline complex. The results reveal that the deposits feature similar geochemical characteristics typical of an alkaline rock series—both are rich in alkali, high in potassium, metaluminous, and poor in Ti, Fe, Mg, and Mn. In terms of REEs, the deposits are strongly rich in light REEs but poor in heavy REEs, with weak negative Eu anomalies. In terms of trace elements, they are rich in large ion lithophile elements Ba, Sr, and Rb but poor in high field-strength elements Nb, Ta, and Hf. Zircon LA-ICP-MS U–Pb dating indicated that the quartz syenite and alkali granite formed in Early Cretaceous at 125.8 ± 1.2 Ma and 127.3 ± 1.0 Ma, respectively; their εHf(t) values are −22.67 to −13.19, with depleted model ages (T_DM) ranging from 1296 Ma to 1675 Ma and crustal model ages (T_DM^C) of 2036–2617 Ma. The Chishan alkaline complex originated from partial of the EM I-type (enriched mantle I) lithospheric mantle with assimilation of ancient crustal materials. The complex is of the same origin as the REE deposit, and developed in an extensional setting that resulted from plate subduction and lithospheric thinning and upwelling in the eastern area of the North China Craton.

华北克拉通破坏早期的岩浆-成矿响应过程是理解该克拉通破坏演化的关键。铜石杂岩体位于华北克拉通东南缘的鲁西归来庄金矿田内，其形成演化与区内金矿化密切相关，但其形成时代、岩浆源区及其与金矿化的成因联系仍存在争议。本文以该杂岩体两大主体岩石二长闪长玢岩和正长斑岩为研究对象，对其开展了系统的锆石U-Pb定年、锆石微量元素与Hf-O同位素、全岩地球化学及Sr-Nd-Pb同位素分析。定年结果显示二长闪长玢岩年龄为175.9±4.3Ma和176.3±1.8Ma，正长斑岩年龄为174.7±0.6Ma和175.0±1.6Ma。地球化学与同位素数据表明，二长闪长玢岩起源于华北克拉通富集岩石圈地幔的部分熔融，其源区受华北拆沉下地壳、俯冲扬子陆壳组分以及古太平洋板片相关流体的共同改造；而正长斑岩则由软流圈地幔部分熔融产生，其母岩浆在深部混合了华北克拉通拆沉下地壳物质。该杂岩体具有高氧逸度与高含水量特征(二长闪长玢岩: ΔFMQ=1.89, Eu_N/Eu_N^*=0.64~0.98; 正长斑岩: ΔFMQ=2.23, Eu_N/Eu_N^*=0.34~0.67)，指示其岩浆体系有利于金的活化与迁移，具备良好的成矿潜力。特别是，正长斑岩比二长闪长玢岩显示出更高的金成矿潜力。归来庄金矿床中的黄铁矿与正长斑岩全岩具有相似的Pb同位素组成，表明岩体可能为成矿作用提供了主要的金属来源。结合矿床内各类金矿化严格受该杂岩体控制，本文认为铜石杂岩体与归来庄金矿田在时空上密切共生，构成一个典型的潜火山岩浆-热液成矿系统。综合研究提出，铜石杂岩体和归来庄金矿床的形成与扬子板块、古太平洋板块的先后俯冲密切相关，共同代表了华北克拉通破坏早期的岩浆演化与金成矿事件。其中，扬子板块的俯冲通过地幔交代改造并弱化华北岩石圈地幔，而古太平洋板块的俯冲触发大陆碰撞形成的岩石圈山根拆沉与软流圈上涌，为白垩纪华北大规模克拉通破坏奠定了物质与结构基础。