| 胶西北丛家花岗闪长岩体SHRIMP锆石U-Pb年代学研究 |
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| 关键词:Congjia intrusion Guojialing SHRIMP zircon U-Pb dating northwest Jiaodong area inherited zircon mother rock |
| 基金项目:国家自然科学基金项目(编号: 41372086; 41503038; 41572068); 国土资源部公益性科研专项(编号: 201511029) |
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| Zircon SHRIMP U-Pb Geochronology of Congjia Granodiorite from Northwest Jiaodong Area |
| Northwest Jiaodong area is the most important gold mineralization concentration area in China. The relationship between Mesozoic granitoid and gold deposits in northwest Jiaodong area is very imtimate. In this paper, the authors studied the geological background and zircon SHRIMP geochronology of Congjia intrusion from Guojialing sequence. The dating result of zircons from porphyritic granodiorite is (127±1) Ma, suggesting that it was an early Cretaceous intrusion. The difference between ages from each intrusions of Guojialing sequence is very insignificant, indicating that they were emplaced almost at the same time at ca. 127.9 Ma. Multiple stage inherited zircon ages of Ar3, Pt1, J3 obtained from zircons in Congjia intrusion and former researches imply that the magma source regions of Guojialing sequence are very complicated. There are Precambrian basement and late Jurassic Linglong sequence from Jiaoliao block, Triassic syn-collision granitoid from Jiaonan–Weihai orogenic belt, and the addition of mantle-derived components. Crust-derived components are mainly made up of Linglong sequence. There exists very imtimate relationship between Guojialing sequence and gold deposits in northwest Jiaodong area. From the aspect of time, Guojialing sequence was formed 5~10 Ma earlier than gold deposits in northwest Jiaodong area, in good accordance with the diagenesis-mineralization time gap between gold deposits and their cognate magmatites. From the aspect of space, it is inferred that insidious Guojialing sequence exists under every three main ore-controlling fault zones in northwest Jiaodong area, and gold deposits occur always together with Guojialing sequence. From the aspect of material composition, Guojialing sequence is relatively richer in sodium than other early Cretaceous magmatites, which might have resulted from segregation of gold-bearing potassium-rich hydrothermal solution before its emplacement. Thus, Guojialing sequence is closer in time to the mother rock of gold deposits in northwest Jiaodong area. |
| GENG Ke,WANG Rui-jiang,LI Hong-kui,LIANG Tai-tao,ZHANG Yu-bo.2016.Zircon SHRIMP U-Pb Geochronology of Congjia Granodiorite from Northwest Jiaodong Area[J].Acta Geoscientica Sinica,37(1):90-100. |
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