新疆青玉的宝石学特征及成矿作用分析

发布时间：2018-03-25 03:32

本文选题：青玉　切入点：矿物组成　出处：《成都理工大学》2017年硕士论文

【摘要】：自古以来,玉石受到了中华民族的喜爱,它是中华民族文化的起源之一。软玉具有多重价值,因此对其的研究长期以来便受到了重视,但针对矿床学的研究较少。本次研究以市场调查为基础,收集了新疆和青海两个产地四种类型的样品,包括且末青(含有青、糖及墨色)、塔青(黑青色)、青海料(青色)软玉及一种有代表性的仿品;对新疆且末矿区进行野外地质调查和系统采样,分析成矿作用。通过切片镜下观察、电子探针、红外光谱及化学元素和微量元素分析等手段对样品进行分析检测,以研究其矿物成分及镜下显微结构特征。本文通过对青玉进行宝石学和岩石学的研究,重点对新疆产地软玉的岩相学特征和成矿作用进行探讨,从而明确致色元素、仿品鉴定特征、矿床成因及成矿模式方面的问题。研究区地处软玉成矿带内,区域上已发现多处软玉矿点。区域断裂构造发育,以扭性为特征,岩浆岩活动频繁。研究区出露地层的岩性主要为白云石大理岩,构造较为发育,岩浆岩活动较频繁。共计发现五条顺层产出的玉石矿体,主要呈似层状、透镜状,规模较小,为杂色软玉矿体。本次研究表明,青玉的透闪石含量多在95%左右,另有少量副矿物,如透辉石、金云母等。软玉的结构以毛毡状隐晶质变晶结构为典型、矿物粒度细,呈毛毡状交织在一起,这点可能是软玉韧度较大的原因之一。对红外光谱的研究结果表明,1150-850cm-1为强吸收区,最强吸收峰在980-1000cm-1。常量元素研究结果表明每个地区软玉的氧化物含量较为稳定,微量元素研究表明不同软玉的某些元素含量不同,例如从白玉到青玉,FeO的含量依次升高。另外对稀土元素研究表明不同颜色软玉特征略有区别;而对同位素的研究表明热液来源不单一。矿区地层主要出露白云石大理岩;根据对围岩Ca/Mg的研究,认为新疆软玉矿体围岩主要为富Mg大理岩,而青海地区软玉矿床的围岩为富Ca白云岩或大理岩。软玉矿床的成因分为两种:一种是碧玉矿床,与超基性岩有关,认为碧玉矿床成因属超基性岩蚀变成因;其他颜色为接触交代变质成因。另外,软玉矿床类似于矽卡岩型矿床,产于中-酸性侵入体与碳酸盐岩的接触带,具有多期次、多阶段性。通过对比发现,东昆仑和西昆仑地区的软玉成矿条件在成矿围岩、流体等方面均存在比较明显的差异。最后,根据资料及矿区成矿的特点,将软玉矿床的控矿因素归纳为三点:侵入岩、围岩岩性、构造。侵入岩一般为中-酸性岩浆,围岩岩性主要为大理岩(可见白云岩),构造为深大断裂次一级的断裂构造。
[Abstract]:Since ancient times, jade has been loved by the Chinese nation, and it is one of the origins of Chinese culture. On the basis of market research, four types of samples from Xinjiang and Qinghai were collected, including Qiwuqing (containing Qingqing). Sugar and ink, Tachin (black and blue) nephrite and a typical imitation; field geological survey and systematic sampling of Qiemo mining area, Xinjiang, to analyze mineralization. Infrared spectroscopy and chemical element and trace element analysis were used to analyze and detect the samples in order to study their mineral composition and microscopic structure under microscope. In this paper, the gemology and petrology of sapphire were studied. The petrographic characteristics and metallogenic process of nephrite from Xinjiang are discussed in order to clarify the problems of color elements, identification characteristics of imitation products, ore deposit genesis and metallogenic model. The study area is located in the Nephrite metallogenic belt, and the study area is located in the Nephrite metallogenic belt. A number of nephrite ore spots have been found in the region. The regional fault structures are developed, characterized by torsion and frequent magmatic activities. The lithology of the outcrop strata in the study area is mainly dolomite marble, and the structure is relatively developed. The magmatic rock activity is more frequent. It is found that five jade orebodies, mainly layered, lenticular and small in size, are mainly composed of nephrite ore bodies. The results show that the tremolite content of sapphire is about 95%. Other minor minerals, such as diopside, phlogopite, etc., the structure of nephrite is characterized by felt-shaped cryptic metamorphic structure. This may be one of the reasons for the high toughness of nephrite. The results of infrared spectra show that the strong absorption region is 1150-850cm-1, and the strongest absorption peak is 980-1000cm-1.The results of constant element analysis show that the oxide content of nephrite is relatively stable in each region. Trace element studies show that the contents of some elements in different nephrite are different, for example, the content of Feo from white jade to sapphire increases in turn. In addition, the study of rare earth elements shows that the characteristics of different colors of nephrite are slightly different. The study of isotopes shows that the source of hydrothermal solution is not single. The strata of mining area are mainly exposed dolomite marble. Based on the study of surrounding rock Ca/Mg, it is considered that the surrounding rock of Xinjiang nephrite ore body is mainly Mg-rich marble. The rocks of the Nephrite deposit in Qinghai area are Ca rich dolomite or marble. The origin of Nephrite deposit can be divided into two types: one is Jasper deposit, which is related to ultrabasic rock, and it is considered that the genesis of the deposit belongs to the cause of ultrabasic rock erosion; The other colors are contact metasomatic metamorphism. In addition, the nephrite deposit is similar to skarn type deposit and occurs in the contact zone between intermediate-acid intrusions and carbonate rocks. The ore-forming conditions of nephrite in East Kunlun and West Kunlun are obviously different in ore-forming surrounding rock and fluid. Finally, according to the data and the ore-forming characteristics of ore area, the ore-controlling factors of nephrite deposit are divided into three points: intrusive rock, intrusive rock, etc. The intrusive rocks are generally intermediate-acid magma, and the surrounding rock lithology is mainly marble (dolomite can be seen, the structure is the subgrade fault structure of deep and large fault.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P619.28

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