Abstract Late Mesozoic magmatism and its associated polymetallic mineralization are widespread in the Chizhou area, forming one of the ore clusters in the Lower Yangtze River Metallogenic Belt (LYRMB). The mineralization in the Chizhou area, however, is not as same as the other ore clusters (e.g., Tongling, Edong, and Jiurui) in age, source, and mechanism. In this study, we used zircon U Pb dating, Lu Hf isotopes, whole-rock geochemistry, and Sr-Nd-Pb isotopes to investigate six ore-bearing intrusions in the Chizhou area. These intrusions comprise high-K calc-alkaline series pyroxene diorite, quartz diorite (porphyry), and granodiorite (porphyry). LA-ICP-MS zircon U Pb dating results indicate that these intrusions formed between 150 and 141 Ma. The mafic intrusion, the Xiaodingchong pyroxene diorite, has low SiO2 and MgO contents, arc-like trace element characteristics, as well as enriched Sr-Nd-Hf isotopic compositions and high radiogenic Pb isotopes, indicating that it was derived from an enriched lithospheric mantle source. The acid intrusion, the Pailou granite, has high SiO2, enriched Sr-Nd-Hf isotopic compositions, continental crust-like geochemical characteristics, and adakitic affinities, such as high Sr, low Y, and low Yb, suggesting that the Pailou granite was derived from partial melting of the Meso-Neoproterozoic thickened accretionary arc crust. The remaining intermediate-acid ore-bearing intrusions were produced by magma mixing of these two end members. The metallogenic deposits in the Chizhou area were mainly controlled by two different magma sources: an enriched mantle and the accreted Meso-Neoproterozoic crust. Furthermore, the low Ti-in-zircon temperatures and the variable amounts of inherited zircons indicate that the Late Mesozoic Chizhou ore-bearing intrusions were formed in hydrous conditions, which is consistent with the tectonic evolution of the low-angle paleo-Pacific plate subduction with slab foundering and roll-back.

中文翻译：

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长江下游成矿带池州地区晚中生代岩浆岩年代学和地球化学：岩石成因和构造背景的制约

摘要 晚中生代岩浆作用及其伴生的多金属矿化在池州地区广泛分布，是长江下游成矿带（LYRMB）的矿群之一。然而，池州地区的矿化在年龄、来源和机制上与其他矿簇（如铜陵、鄂东和九瑞）不同。在这项研究中，我们使用锆石 U Pb 定年、Lu Hf 同位素、全岩地球化学和 Sr-Nd-Pb 同位素调查了池州地区的 6 个含矿侵入体。这些侵入体包括高钾钙碱性系列辉石闪长岩、石英闪长岩（斑岩）和花岗闪长岩（斑岩）。LA-ICP-MS 锆石 U Pb 定年结果表明这些侵入体形成于 150 至 141 Ma。镁铁质侵入体，小鼎冲辉石闪长岩，SiO2 和 MgO 含量低，弧状微量元素特征，以及富集的 Sr-Nd-Hf 同位素组成和高放射性 Pb 同位素，表明它来自富集的岩石圈地幔源。酸侵入的牌楼花岗岩具有高SiO2、富集的Sr-Nd-Hf同位素组成、类陆壳地球化学特征以及高Sr、低Y、低Yb等埃达克岩亲和性，表明牌楼花岗岩是来源于中-新元古代加厚的增生弧地壳的部分熔融。剩余的中酸性含矿侵入体是由这两个端部的岩浆混合产生的。池州地区的成矿矿床主要受两种不同的岩浆源控制：富集地幔和增生的中新元古代地壳。此外，