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    华北板块北缘中段二叠纪岩浆岩年代学、地球化学及锆石Hf同位素测试数据集

    Dataset of Chronology, Geochemistry and Zircon Hf Isotopes of Permian Magmatites in the Middle Section of the Northern Margin of North China Craton

    • 摘要: 华北板块北缘中段位于华北板块与白乃庙弧的结合处,以赤峰-白云鄂博断裂为界,南、北归属不同的大地构造单元,并且具有不同的基底属性。二叠纪岩浆岩在华北板块北缘广泛分布,断裂带两侧均有出露,源区组成十分复杂,制约着对其岩石成因及构造背景的深刻认识。本文通过对横跨赤峰–白云鄂博断裂的“北柳图庙幅等4幅区调”和“乌兰布拉格幅等2幅区调”2个项目的1∶50 000区调工作,共计6个1∶50 000图幅内的二叠纪岩浆岩的年代学、地球化学及锆石Hf同位素测试数据进行整合、分析,为进一步研究华北板块北缘中段二叠纪岩浆岩的源区及构造-岩浆演化过程提供详实的数据支撑。区内二叠纪侵入岩广泛出露,岩石类型以花岗闪长岩、(石英)闪长岩及二长花岗岩为主,并含有少量的正长花岗岩。二叠纪火山岩主要分布在断裂带以南,岩性包括安山质、英安质及少量流纹质火山岩。锆石U–Pb测年表明工作区内二叠纪岩浆岩的形成时代主要为中–晚二叠世,断裂带南北两侧的岩浆岩具有截然不同的锆石Hf同位素特征,总体而言,南侧相对富集,北侧相对亏损。本数据集包括3个.xls类型文件(Zircon U–Pb dating data.xls,Zircon Hf isotope data.xls,Whole-rock geochemistry data.xls),分别记录了104件样品的地球化学数据、16件样品的锆石U–Pb测年数据和12件样品的锆石Hf同位素数据。本数据集测试样品主要在中国地质调查局天津地质调查中心实验测试中心完成,数据质量可靠。

       

      Abstract: The middle section of the northern margin of the North China Craton (also referred to as the study area) is situated in the junction between the North China Craton and Bainaimiao arc. With the Chifeng–Bayan Obo fault as the boundary, its southern and northern parts fall within different geotectonic units and have different basement features. Permian magmatites are widely distributed across the northern margin of the North China Craton and are exposed on both sides of the fault zone. Their provenance consists of very complex components, constricting fuller understanding of the petrogenesis and tectonic background of the magmatites. The Chifeng–Bayan Obo fault is covered by two geological survey projects, one involves four map sheets including the Beiliutumiao map sheet, and the other covers two map sheets including the Wulanbulage map sheet. In this paper, the testing data of chronology, geochemistry, and zircon Hf isotopes of the Permian magmatites in all six map sheets from the two projects were integrated and analyzed based on the regional geological surveys on a scale of 1∶50 000 of the two projects. The aim is to provide detailed and accurate data for further research of the provenance and the tectonic-magmatic evolution process of Permian magmatites in the study area. Furthermore, Permian intrusions are also widely exposed in the study area, which mainly include granodiorites, (quartz) diorite, monzogranite, and a small number of syenite granites. Permian volcanics are mainly distributed to the south of the fault zone and consist of andesitic and dacitic volcanics as well as a small number of rhyolitic volcanics. As shown by zircon U–Pb dating, the Permian magmatites within the study area were mainly formed in mid–late Permian, and the magmatites on the northern and southern sides of the fault zone have distinctly different zircon Hf isotopic characteristics. In short, zircon Hf isotopes are rich on the southern side but depleted on the northern side. The datasets of chronology, geochemistry and zircon Hf isotopes of Permian magmatites in the study area (also referred to as the Dataset) include three.xls files (Zircon U–Pb dating data.xls, Zircon Hf isotope data.xls and Whole-rock geochemistry data.xls), which are comprised of data on the petrogeochemistry of 104 samples, zircon U–Pb dating of 16 samples and zircon Hf isotopes of 12 samples. Samples collected for the Dataset were mainly tested in the Experiment and Test Center of Tianjin Center, China Geological Survey, and thus the data obtained are credible.

       

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