【摘要】 首次报道了鲁西地区铜石岩体的锆石SHRIMPU Pb年龄结果。通过对斑状细粒闪长岩中单颗粒锆石 1 8个样品点的分析 ,获得了两组谐和年龄数据 ,其中有 1 0个分析点的2 0 6Pb/ 2 3 8U年龄为 1 6 7.9～ 1 83Ma ,加权平均值为 (1 75 .7± 3.8)Ma ;另外 8个分析点的2 0 7Pb/ 2 0 6Pb年龄为 2 5 0 2～ 2 5 5 4Ma ,加权平均值为 (2 5 1 8± 1 1 )Ma。二长斑岩样品仅获得 2个2 0 7Pb/ 2 0 6Pb年龄数据 ,在 2 4 85～ 2 5 1 2Ma之间。(1 75 .7± 3.8)Ma指示了铜石岩体的结晶年龄为中侏罗世 ,(2 5 1 8± 1 1 )Ma代表了岩体侵位过程中捕获的新太古代五台期锆石的年龄。根据SHRIMPU Pb年龄结果 ,认为鲁西地区存在燕山早期构造岩浆热事件 ,与之有关的归来庄金矿也在此时期形成更多还原

【Abstract】 This paper reports the SHRIMP U-Pb age of zircon from Tongshi magmatic complex in western Shandong. Eighteen analyses on zircon grains from porphyritic fine-grained diorite gave two concordant groups of ages, in which ten analyses presented ²⁰⁶ Pb/²³⁸ U ages from 167.9 Ma to 183 Ma with a weighted mean age at （175.7±3.8） Ma, and the other eight analyses provided ²⁰⁷ Pb/²⁰⁶ Pb ages from （2 502） Ma to 2 554 Ma with a weighted mean （2 518±11） Ma. Two analyses on zircon grains from syenite porphyry yield the ages of 2 485 Ma and 2 512 Ma, respectively. The age of （175.7±3.8） Ma indicates that the crystallization of Tongshi magmatic complex occurred in the middle Jurassic epoch. The age of （2 518±11） Ma is interpreted as the age of inherited magmatic zircon in Neo-archean Wutai period. According to the SHRIMP U-Pb data of zircon, the authors consider that there existed the early Yanshanian tectonic-magmatic thermal events in western Shandong, and the Guilaizhuang gold deposit related to Tongshi magmatic complex was formed between 170 Ma and 160 Ma.更多还原