| Linglong gold deposit is one of the most significant quartz- vein type gold deposits in Zhao- Ye metallogenic belt, Jiaodong Peninsula. This study, through the sampling of granites and dykes systematically in the Xishan ore block(- 50 m level) of the Linglong gold deposit and the detailed fieldworks, determines their characteristics of spatial distribution. By adopting the methods of SHRIMP zircon U- Pb isotope dating, analyses of major, trace and rare earth elements and Sr- Nd- Pb isotope compositions determination, and combining to the indoor materials arrangement, it devotes to discuss petrogenesis, source materials of the magmatic rocks, magmatism feature and the metallogenic dynamics of the Linglong gold deposit.Magmatic rocks found in Linglong gold deposit are mainly neutral dykes(mainly diorite and diorite porphyrite), mafic dykes(mainly lamprophyre and diabase) and granite(mainly granite, granodiorite, monzonitic granite, moyite and so on). The SHRIMP zircon U- Pb dating data show that two periods of granite formed in the Early Cretaceous(112.5 ± 2.1Ma, 106.9 ± 2.3Ma) and late Jurassic(144.8 ± 2.7Ma), neutral dykes age of 160.4 ± 4.3Ma, mafic dykes age of 139 ± 2Ma. The analysis results of major elements tells that the meso-basic dykes and granite in the Linglong gold deposit belong to peraluminous and high- K calc-alkaline series. The trace element analysis results show that the performance of magmatic rocks are enriched of LREE and HILE, and depleted of high field strength elements, and significant "Nb- Ta " and " Ti " Valley features, where in the degree of acidity granite high field strength elements a larger extend loss, and the neutral dykes loss more than and the mafic dykes. The meso-basic dykes have unconspicuous abnormal situation to the element Eu, but part of granites have a minor irregularity with the element Eu. The result of Sr- Nd- Pb isotopic analysis shows that the meso-basic dykes have high Sr content, and granite have middle Sr content. TheεNd(t) of the granite is about the range of-21.7~-20. The mafic dykes’ sεNd(t)(-15.7~-13.5) is higher than the neutral dykes’ s(-18.1~-15.8). The source of element Pb for the granite and the meso-basic dykes come from the deep crust and orogenic belts mainly. From the above, granites are crustal source region and effected by the enriched mantle. The neutral dikes a source region of mantle contamination of the deep crust. The mafic dikes formed in the younger crust, and its source of material comes from enriched mantle, and effected by some extend crustal contamination in the late evolution.The Linglong gold deposit formed in the early Cretaceous, and the mafic dykes are formed with the same period of concomitant. They not only provide heat and power for increasing the fluid-containing ore mineralization, but also provide a closed condition. At the same time, some granites formed in the deep crust. It compete with the ore bearing hydrothermal which rise from the the crust for space and heat, but it can carry the ore-bearing hydrothermal. To the Late Jurassic, the neutral dykes and acidic granite have no temporal relationship with the mineralization for the genesis in the Linglong gold deposit. |
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