The Tietonggou pluton is mainly composed of gabbroic diorite and diorite. The petrology, zircon U-Pb age, and geochemistry of the Tietonggou diorite have been studied to determine its petrogenesis and metallogenic significance. The diorite samples have 56–58 wt% SiO2 and 11–14 wt% Al2O3 and are peraluminous and sodic (Na2O/K2O = 1.29–2.07). All the samples are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs; e.g., Rb, Ba, and Sr) but depleted in heavy rare earth elements (HREEs) and high field strength elements (HFSEs; e.g., Zr, Nb, and Ta), suggesting subduction-related affinities. The rocks have narrow ranges of (206Pb/204Pb)t (18.5–19.0), (207Pb/204Pb)t (15.71–15.75), and (208Pb/204Pb)t (38.4–39.0) ratios, respectively. Zircons from the Tietonggou diorite yielded a weighted average U-Pb age of 132.86 ± 0.92 Ma (MSWD = 0.48), whilst those from the nearby Laowa diorite yielded 129.72 ± 0.61 Ma (MSWD = 1.05). This suggests that the rocks represent Early Cretaceous plutons, coeval with the peak lithospheric thinning in eastern North China Craton (NCC). The magma likely originated from partial melting of the enriched lithospheric mantle and was contaminated by ancient lower NCC crustal materials. Our study clarifies the tectonic background of the Tietonggou pluton and provides support for the study of the genesis of Fe–skarn deposits in western Shandong.

中文翻译：

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早白垩世铁通沟闪长岩的岩石成因及其地质意义

铁通沟岩体主要由辉长闪长岩和闪长岩组成。对铁通沟闪长岩的岩石学、锆石U-Pb年龄和地球化学进行了研究，以确定其岩石成因和成矿意义。闪长岩样品含有 56–58 wt% SiO2 和 11–14 wt% Al2O3，是过铝质和钠质 (Na2O/K2O = 1.29–2.07)。所有样品均富含轻稀土元素 (LREE) 和大离子亲石元素 (LILE；例如 Rb、Ba 和 Sr)，但缺乏重稀土元素 (HREE) 和高场强元素 (HFSE；例如、Zr、Nb 和 Ta），表明与俯冲相关的亲和力。岩石的 (206Pb/204Pb)t (18.5–19.0)、(207Pb/204Pb)t (15.71–15.75) 和 (208Pb/204Pb)t (38.4–39.0) 比率范围较窄。铁通沟闪长岩中的锆石的加权平均 U-Pb 年龄为 132.86 ± 0.92 Ma (MSWD = 0.48)，而附近老洼闪长岩中的锆石的加权平均 U-Pb 年龄为 129.72 ± 0.61 Ma (MSWD = 1.05)。这表明这些岩石代表早白垩世岩体，与华北克拉通（NCC）东部岩石圈减薄的峰值同时期。岩浆可能源自富集岩石圈地幔的部分熔融，并受到古老的华北克拉通下地壳物质的污染。该研究阐明了铁通沟岩体的构造背景，为鲁西铁矽卡岩矿床成因研究提供了支持。