内蒙古巴彦哈尔金矿区花岗岩年代学及地球化学研究

发布时间：2018-06-28 00:37

本文选题：内蒙古 + 巴彦　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：巴彦哈尔金矿床位于华北陆块与西伯利亚板块缝合带南侧,属于二连浩特--锡林浩特金、铁及铜成矿带。区内前寒武系和上古生界地层出露广泛,温都尔庙地层可能是金成矿物质来源之一。受华北古陆块、古亚洲洋壳和西伯利亚板块多期次俯冲、碰撞和对接作用影响,区内断裂构造广泛发育,巴彦哈尔金矿床与交其尔推覆构造及其韧性剪切带关系密切。区内侵入岩从加里东期至燕山期岩浆岩均有发育,且区内矿床多与海西晚期-印支早期的岩浆岩关系密切。巴彦哈尔金矿床金矿化主要发育于侵入岩带旁侧的强糜棱岩化温都尔庙群云母片岩中,带内发育低温热液成矿作用所形成的含金石英(硅质)脉。侧矿体主要赋存在石英脉及其两侧片岩内,并以后者为主。前人将巴彦哈拉图序列花岗闪长岩的锆石U-Pb年龄363Ma作为该矿床的成矿年龄。本次研究结合矿区内次生晕及稀土元素分析结果,认为矿区内晚期黑云母花岗岩与成矿关系密切。同时根据岩体与蛇绿岩体的穿插关系,以及相似构造环境已知金矿床年龄对比,提出巴彦哈尔金矿床与三叠纪花岗岩成矿关系密切,厘定其成矿年龄为226.5±4.1Ma。本文对宝力道石炭世花岗岩和早二叠及晚三叠哈拉图花岗岩进行了详细的研究。宝力道花岗岩为钙碱性准铝质花岗岩,在Rb-(Yb+Ta)等大地构造判别图解上落于后碰撞区域,其εNd(t)0,认为在宝力道花岗岩的构造环境可能为石炭世向二叠世构造转换的后碰撞环境。哈拉图花岗岩为强过铝质,可在光学显微镜下可观察到自形原生白云母,且其Ti、P和εNd(t)值较宝力道岩体更低,认为其形成于后造山伸展环境。为该区域石炭二叠三叠构造演化历史确定,提供了一定参考意义。
[Abstract]:The Bayanhar gold deposit is located on the southern side of the North China continental block and the Siberian plate suture zone, belonging to the Erlianhaot-Xilinhaote gold, iron and copper metallogenic belt. The Precambrian and Upper Paleozoic strata are widely exposed in this area, and the Wenduermiao formation may be one of the sources of gold forming materials. Affected by multiple subduction, collision and docking of the North China paleocontinent block, paleo-Asian oceanic crust and Siberian plate, the fault structures are widely developed in the area. The Bayan Haer gold deposit is closely related to the Jiaoqier nappe structure and its ductile shear zone. The intrusive rocks developed from Caledonian to Yanshanian, and the ore deposits in the area are closely related to the magmatic rocks of late Hercynian and early Indosinian. The gold mineralization of Bayanhar gold deposit is mainly developed in the mica schist of strong mylonitic Wenduermiao group on the side of the intrusive rock belt. The gold bearing quartz (siliceous) vein formed by low temperature hydrothermal mineralization is developed in the belt. The lateral orebodies mainly occur in quartz veins and schist on both sides, and the latter is the main one. The zircon U-Pb age of the granodiorite from the Bayanharatu sequence was used as the metallogenic age of the deposit. Combined with the results of secondary halo and rare earth element analysis, it is concluded that the late biotite granites are closely related to mineralization. At the same time, according to the intercalation relationship between the ore-body and ophiolitic rock mass, and the age comparison of known gold deposits in similar tectonic environments, it is suggested that the Bayan gold deposit is closely related to the Triassic granite mineralization, and its metallogenic age is 226.5 卤4.1 Ma. In this paper, the Bao Lidao Carboniferous granites and the early Permian and late Triassic Haradu granites have been studied in detail. The Bao Lidao granites are calc-alkaline quasi-aluminous granites, which fall to the post-collision area in the Rb- (YbTa) tectonic discriminant diagram, and 蔚 ND (t) 0. It is considered that the tectonic environment of the Bao Lidao granites may be the post-collision environment of the Carboniferous to Permian tectonic transformation. The Haradu granite is strongly peraluminous and can be observed under optical microscope. The values of Tip and 蔚 ND (t) are lower than those of Bao Lidao, which is considered to be formed in the post-orogenic extensional environment. It provides a reference for determining the evolution history of Carboniferous Permian and Triassic structures in this region.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.51;P588.121

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