中文摘要：

太行山南段是我国东部重要的金属成矿区。本文首次报道了太行山南段洪山岩体的金属成矿作用，对含矿的正长斑岩开展了系统的年代学、岩石地球化学及Hf同位素的分析工作。详细的野外观察表明，洪山岩体内具有典型的斑岩型矿化特点，并厘定出含矿正长斑岩。LA ICP MS锆石U Pb定年结果表明，洪山正长斑岩成岩年龄为13045~1314Ma，晚于洪山正长岩形成年龄（132~135Ma），成矿时代略晚于本区矽卡岩型铁矿的成矿年龄（133~137Ma），处在太行山地区中生代侵入岩活动高峰期内（120~140Ma），属于太行山地区后碰撞构造伸展阶段的产物。详细的岩石地球化学研究表明，洪山正长斑岩具有高硅（SiO2=63.72%~67.63%）、高钾（K2O/Na2O=0.73~1.36）和富碱（K2O＋Na2O=12.34%~12.73%）的特点，属于钾玄岩系列岩石。岩体轻稀土元素富集（LREE/HREE=9.32~12.43），不具铕异常（δEu=0.93~1.05），富集大离子亲石元素（Rb、Th、U、K）而亏损高场强元素（Nb、Ta、Ti）。2件样品24个测点的锆石εHf（t）值具有较大的变化范围（-24.4~-10.3），对应的地壳模式年龄集中于1.6~2.7Ga。综合分析表明，正长斑岩是＂EMⅠ型＂富集地幔部分熔融的产物，岩浆在上涌的过程中受到下地壳物质的混染，形成壳幔混源的富钾含矿岩浆，并最终导致洪山斑岩型Cu矿化的发生。

英文摘要：

The Hongshan complex is an important component of the Mesozoic intrusive rocks in the North Taihang Mountain, and is especially significant in alkaline rocks. We firstly report the porphyry Cu mineralization from the Hongshan complex in the southern Taihang Mountains and carried out a comprehensive research.Methods：In this paper, zircon U Pb dating, petrogeochemical investigation and zircon Hf isotope analysis of the ore bearing syenite porphyry are studied to constrain its geochronology and petrogenesis.Results：LA ICP MS zircon U Pb choronology indicates that the porphyry was emplaced at 130.45~131.4Ma, slightly older than the Hongshan syenite （132~135Ma） and the formation of the Han Xing type iron skarn deposits （133~137Ma）. It shows the Hongshan ore bearing syenite porphyry was emplaced in the summit of magma activity in the region of Taihang Mountains and formed in the timing of large scale lithospheric thinning in North China Block. The syenite porphyry is silica rich （SiO2=63.72%~67.63%）, potassium rich （K2O/Na2O=0.73~1.36） and alkali rich （K2O＋Na2O=12.34%~12.73%）, belonging to shoshonitic series, with the characteristics of LREE enrichment, HREE depletion, and no Eu anomaly （δEu=0.93~1.05）. The syenite porphyry is enriched in LILEs such as Rb、Th、U、K, etc, and delepted in HFSEs such as Nb、Ta、Ti, etc. 24 analyses from two samples of the ore bearing syenite porphyry give a wide range zircon εHf（t）values （-24.4~-10.3） and varying Hf isotope crustal model ages （1.6~2.7Ga）. Conclusions：All of the above datas imply that the magma originated from partial melting of the EMI type mantle source which was contaminated by crustal materials in the process of magmatic upwelling to form a potassium rich ore bearing magma with mixed sources of the crust and the mantle.