辽宁宽甸石墨矿地球化学特征及成矿研究

发布时间：2018-03-01 10:32

本文关键词： 地球化学锆石年代学碳质来源矿床成因　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：胶-辽-吉活动带位于华北克拉通的东段,是我国古元古代物质组成及演化最为复杂、构造带保存较完整的地区。辽东宽甸地区石墨矿带位于华北板块北缘的东段,本文主要通过对辽宁宽甸石墨矿的石墨斜长片麻岩中和石墨片岩,对其进行岩石矿物学及岩石地球化学、U-Pb年代学等研究,进一步确定该区石墨矿碳质来源及矿床成因。宽甸石墨矿主要赋存于石墨斜长片麻岩中和石墨黑云片岩等。矿石矿物主要为石墨,脉石矿物斜长石、绿泥石、云母、石英、方解石等。矿石结构主要为鳞片粒状变晶结构,他形粒状结构。脉石矿物主要由石英、斜长石、绿泥石、黑云母、角闪石、钾长石、及少量的不透明矿物组成。主微量元素和稀土元素特征显示宽甸变质岩具有高硅铝、富钾的特点,富集大离子亲石元素,轻稀土元素富集,重稀土平坦,Sr、Nb、P、Ti元素具有明显的亏损,并具有Eu负异常。K-A、Zr/Ti O2-Ni等判别图解,表明宽甸石墨矿的原岩应为沉积岩,源区物质以长英质岩石为主;TFe O+Mg O-Ti O2等构造判别图解,显示辽河群宽甸地区变质岩形成的构造背景为被动大陆边缘。宽甸石墨矿原岩以陆源碎屑岩为主,夹杂有泥灰岩、热水沉积岩等,浊积岩系沉积.宽甸岩组的物源成分以长英质岩石为主,并含有古老再循环沉积物及火成物源。其形成的构造环境应属于被动大陆边缘。本文选取宽甸变质岩系的石墨斜长片麻岩(KD-16)进行SHRIMP U-Pb年代学研究,时间跨度较大,表明石墨矿的形成是一个漫长的历史过程。结合资料,本文研究认为该区石墨矿碳质来源以陆源碎屑岩为主,夹杂有泥灰岩、热水沉积岩等,浊积岩系沉积,是一套夹碳酸盐岩富含碳质的粘土岩建造。宽甸岩组的物源成分以长英质岩石为主,并含有古老再循环沉积物及火成物源。其形成的构造环境应属于被动大陆边缘。粘土—半粘土质岩石,在由陆块碰撞拼合引发的区域变质作用和热液作用条件下,经低角闪岩相的区域变质作用,发生混合岩化,经重结晶、伟晶岩化、少量重熔(形成脉体)、早期交代作用及后期的水化作用等,形成了石墨矿床。
[Abstract]:The Jiaoliao-Jiaoji active belt is located in the eastern part of North China Craton. It is the most complicated area of ancient material composition and evolution of Gu Yuan in China, and the tectonic belt is relatively intact. The graphite ore belt in Kuandian area of eastern Liaoning Province is located in the eastern part of the northern margin of the North China plate. In this paper, the lithologic mineralogy and geochemistry of the graphite plagioclase gneiss and graphite schist of Kuandian graphite ore in Liaoning Province are studied, such as petro-mineralogy and geochemistry, U-Pb geochronology, etc. Kwandian graphite ore mainly occurs in graphite-plagioclase gneiss and graphite black-cloud schist, etc. The ore minerals are mainly graphite, gangue mineral plagioclase, chlorite, mica, quartz, etc, and the ore minerals are mainly graphite, gangue mineral plagioclase, chlorite, mica, quartz, etc. Calcite and so on. The ore structure is mainly scale-granular structure, heteromorphic granular structure. Gangue minerals are mainly quartz, plagioclase, chlorite, biotite, hornblende, potassium feldspar, The main trace elements and rare earth elements show that the Kuandian metamorphic rocks have the characteristics of high Si-Al and K-rich, rich in large ion lithophile elements, light rare earth elements, and heavy rare earths flat SrnbPnbPnnbPnnbPnnnbPnnbPnnnbPnnbPnnnbPnnnbPnnbPnnnbPn@@. The result shows that the source rocks of Kuandian graphite ore should be sedimentary rocks, and the source materials are mainly feldspathic rocks, such as TFE O mg O-TiO 2, etc. It shows that the tectonic setting of metamorphic rocks in Kuandian area of Liaohe Group is passive continental margin. The source compositions of Kuandian formation are mainly felsic rocks. It contains ancient recirculating sediment and igneous material source, and its tectonic environment should belong to the passive continental margin. In this paper, the SHRIMP U-Pb chronology of the KD-16 graphite plagioclase gneiss of Kuandian metamorphic rock series is studied, and the time span is large. It is concluded that the formation of graphite ore is a long historical process. Based on the data, it is considered that the carbonaceous source of graphite ore in this area is mainly continental clastic rock, with marl rock, hot water sedimentary rock and turbidite deposit. It is a set of carbonaceous clay rock formations with carbonaceous intercalation. The source rocks of Kuandian formation are mainly felsic rocks. It contains ancient recirculating sediments and igneous material sources. The tectonic environment formed should belong to the passive continental margin. The clay-semi-clay rocks are formed under the conditions of regional metamorphism and hydrothermal action caused by the collision and assembly of land blocks. Graphite deposits were formed by regional metamorphism of low amphibolite facies, migmatization, recrystallization, pegmatitization, and a small amount of remelting (formation of veins, early metasomatism and later hydration).
【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】：P619.252

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