金川与喀拉通克Cu-Ni硫化物矿床构造环境及成矿作用对比研究

发布时间：2018-06-04 04:55

本文选题：岩浆铜镍硫化物矿床 + 构造环境　；参考：《兰州大学》2015年硕士论文

【摘要】：金川和喀拉通克是我国著名的两个大型铜镍硫化物矿床,具有不同的成矿构造背景,金川矿床产于古老板块边缘的裂谷环境,喀拉通克产于造山后伸展环境；对于我国这类产出铜镍矿的基性-超基性岩来说,金川岩体的基性程度较高,喀拉通克基性程度最低；两矿床的Cu/Ni比值也不同,金川为0.5,而喀拉通克为1.7。上述这些差异表明两矿床在物质来源以及成矿机制等方面的差异。文章在参阅前人的研究资料的基础上,总结了喀拉通克和金川两者的地质构造环境、矿床地球化学特征、矿床分布规律。并根据微量元素数据进行岩体的岩石系列、成矿母岩浆、岩浆源区特征以及地壳混染作用等问题进行了分析讨论,最后通过三维地质建模的手段,对两矿床的岩浆通道以及深部边部找矿潜力进行了预测,以期对该类赋存在小岩体内的岩浆铜镍硫化物矿床的研究以及后期找矿有所帮助,并得出以下几点结论：(1)金川矿床成矿时代为新元古代,喀拉通克矿床形成时代均为晚古生代；成矿构造背景金川为大陆边缘裂谷环境,喀拉通克为造山后伸展环境；这符合Ni-Cu矿床成矿的时空分布规律。成矿母岩浆均为高镁玄武质岩浆；岩浆源区金川为EM1型富集地幔,喀拉通克为亏损的岩石圈地幔；含矿岩体均为多期次侵入的复式岩体,岩浆都受到不同程度的地壳物质混染,硫化物主要在深部熔离,然后以含橄榄石和硫化物的“晶粥”形式贯入成矿。(2)研究了金川和喀拉通克矿床岩浆熔离-深部预富集-多期次贯入成矿模型,并借鉴前人提出的岩浆通道模型,认为深部地质过程-深部预富集的成矿作用是我国同类型矿床的主要成矿机制。(3)通过矿床三维空间地质特征的研究预测其深部岩浆通道和隐伏富矿体的存在；金川由于所处的复杂构造环境,导致深部构造更是复杂,深部找矿工作仍不理想；而喀拉通克则由于其深部见到可能为具有烘烤边的大型地层的捕虏体,其深部存在类似于金川矿床深部的1号矿体和2号矿体这样的大矿、富矿的可能性很大。
[Abstract]:Jinchuan and Karatungk are two famous copper-nickel sulfide deposits in China, which have different metallogenic tectonic background. Jinchuan deposit occurs in the rift environment of the ancient plate margin, and Karatungk occurs in the post-orogenic extensional environment. For the basic-ultrabasic rocks of this type of copper-nickel deposit in China, the basicity of Jinchuan is higher than that of Karatonk, and the Cu/Ni ratio of the two deposits is also different, which is 0.5 in Jinchuan and 1.7 in Karatongk. These differences indicate that the two deposits are different in material source and metallogenic mechanism. Based on the previous research data, this paper summarizes the geological tectonic environment, geochemical characteristics and ore deposit distribution of Karatungk and Jinchuan. Based on trace element data, the rock series, ore-forming magma, characteristics of magma source and crustal mixing are analyzed and discussed. Finally, through the means of three-dimensional geological modeling, The magmatic channel and the prospecting potential of the deep margin of the two deposits are predicted in order to be helpful to the study of the magmatic copper-nickel sulfide deposits which occur in the small rocks and to the later prospecting. The following conclusions are drawn: the metallogenic age of Jinchuan deposit is Neoproterozoic, and the formation age of Karatongk deposit is all late Paleozoic, the metallogenic tectonic setting Jinchuan is continental margin rift environment, and Karatungk is post-orogenic extensional environment. This accords with the temporal and spatial distribution of Ni-Cu deposit. The ore-forming mother magma is high magnesium Black Tortoise magma, Jinchuan magma source area is EM1 enriched mantle, Keratonk is depleted lithospheric mantle, ore-bearing rock mass is multistage intrusive complex rock mass, magma is mixed with different degree of crustal material. The sulfide is mainly melted in the deep, and then the magma melt separation, deep preconcentration and multiple times interpenetration metallogenic model of Jinchuan and Karatungk deposits are studied in the form of "crystal porridge" containing olivine and sulphide. And draw lessons from the previous magmatic channel model, It is considered that deep geological process and deep preenrichment mineralization are the main metallogenic mechanism of the same type deposits in China.) the existence of deep magmatic channels and concealed ore-rich bodies is predicted through the study of the three-dimensional geological characteristics of the deposits. Due to the complex tectonic environment in which Jinchuan is located, the deep structure is even more complicated, and the deep prospecting work is still not ideal. There are large deposits such as No. 1 orebody and No. 2 orebody in the deep part of Jinchuan deposit.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.41;P618.63

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