黔西上二叠统龙潭组煤的矿物学及地球化学特征研究

发布时间：2018-05-28 12:21

本文选题：黔西 + 龙潭组　；参考：《中国地质大学》2015年博士论文

【摘要】：本文主要运用煤化学、矿物学和地球化学的理论和方法,基于对重点矿区的取样分析和研究区勘探成果资料和已发表的文献资料的大量统计数据的归纳总结,系统研究了黔西上二叠统龙潭组煤的煤化学、矿物学和地球化学特征,确定了黔西煤的煤质特征、矿物学特征和地球化学特征,并探讨了异常富集元素的分布特征和成因机理。主要认识如下：1、煤化学黔西煤主要以特低水分含量、低-中灰和低中挥发分产率、中高硫含量煤为特征。黔西煤灰分产率平均23%,受盆缘陆源碎屑和盆心海水侵入的影响,向盆地边缘和盆地中心灰分产率呈增高趋势。灰分产率自龙潭组下部-中部-上部表现出高-低-高的变化趋势,对应于海平面升-降-升的变化趋势,揭示灰分的高低与海平面变化密切相关。由西向东挥发分产率由低中挥发分过渡为特低挥发分,再过渡为低中挥发分产率,主要受区域热变质作用的影响,中部煤的变质程度的增高与含煤地层上覆地层厚度增大有关。煤中硫主要以黄铁矿硫为主。硫分含量自北西向南东逐渐增高,依次由陆相区的低硫煤过渡到过渡相的中硫-高硫煤和海相区的高硫煤。硫分含量自龙潭组下部-中部-上部表现出高-低-高的变化趋势,此与黔西地区龙潭组沉积期海平面升-降-升的变化趋势相吻合。故黔西煤中硫分含量受控于海平面的变化。2、煤矿物学煤中的矿物以石英、黄铁矿和累托石为主,高岭石、伊利石和白铁矿次之,含少量的锐钛矿、蒙脱石、石膏、坡缕石、铁白云石、绿泥石、钠长石、纤铁矾和四水白铁矾,与以前发表过有关该地区煤中富石英和硫化物的分布特征基本一致。受不同地质因素的影响,不同矿区或相同矿区不同煤层的矿物种类及含量存在很大差异。在织金凤凰山煤矿和文家坝煤矿,研究煤样具有特低挥发分产率(8.1%),出现三种与热变质成因有关的矿物组合,即累托石+黄铁矿组合、高岭石+累托石+石英+黄铁矿组合以及石英+累托石组合；在六枝六龙煤矿,研究煤样具有低挥发分产率(18.5%),出现石英+高岭石组合以及石英+伊利石+黄铁矿+白铁矿组合。在煤层中,石英、伊利石、高岭石、硫化物和锐钛矿接近顶板、底板或夹矸层位富集,揭示物源供给强度对其具有重要控制作用；碳酸盐矿物出现于碎屑成因矿物(伊利石,锐钛矿)含量较低的煤分层样品中,说明碎屑物质输入对方解石的形成起阻碍作用；累托石来源于煤变质过程中高岭石向累托石的转化,揭示其为热变质成因；黄铁矿的形成受控于源区物源供给强度、海水影响和沼泽pH条件。煤层中出现两种赋存方式的伊利石,即碎屑伊利石和同生伊利石。碎屑伊利石中钛含量较高,而同生伊利石钛含量很低；累托石以裂隙和细胞充填物方式存在；绿泥石与累托石共存于裂隙之中；黄铁矿以球形多晶草莓状黄铁矿、细胞充填黄铁矿、放射状黄铁矿晶体、有机质基质中的块状黄铁矿、它形分散状黄铁矿和充填裂隙的黄铁矿的形式存在,前三种赋存方式指示了黄铁矿的同生成因,后三种赋存方式指示其为次生成因；部分铁硫酸盐矿物与伊利石共存于细胞充填物中,这并不代表铁硫酸盐矿物的同生成因,而是细胞充填黄铁矿的氧化产物。部分铁硫酸盐矿物聚集于割理／裂隙附近,可能与低温热液流体沿这些渗透性通道侵入而导致先前黄铁矿的氧化有关；石膏也簇集于割理／裂隙周边,其为方解石和硫酸(硫化物氧化而来)反应产物。含有Si和A1成分的石膏的成因可能与石膏形成过程中流体沉淀的铝硅酸盐矿物(尺寸小于EDX光束范围)被包含于石膏晶体中有关。3、煤地球化学所研究的煤层样品常量元素以SiO2、Al2O3和Fe203为主体。除六枝六龙煤矿3号煤中富集K20和轻度富集Ti02,织金文家坝煤矿7号煤中K20含量轻度富集外,其他所采煤层中的常量元素含量与中国煤均值相似或亏损。黔西煤的常量元素均值与中国煤均值相似,但黔西地区黔北煤田煤轻度富集CaO和MgO以及兴义煤田煤轻度富集K2O。六枝六龙煤矿3号煤层富集Ta、Nb、V、Cr、Co、Cu、Sr、Nb和Ba,织金凤凰山煤矿23号煤层富集Li、Se、Nb、Mo和Ta以及27号煤层富集Se、Nb、Mo、Ta和U,织金文家坝煤矿6号煤层富集Ta和Li以及7号煤层富集Ta和Nb外,其他微量元素含量与中国煤微量元素含量均值相似或亏损。从已发表的有关黔西煤的统计资料来看,主要富集V、Cu、Mo、Sb、Ta、U、As和Hg,其他微量元素与中国煤均值相似或亏损；不同煤田煤中微量元素含量存在一定差异,黔北煤田煤富集Cu、Zn、Nb,织纳煤田煤富集V、Cu、Nb、 Mo、U和Ta,六盘水煤田煤富集V、Ni、Cu、Sb、Ta、U和Hg以及兴义煤田煤富集Li、V、Cr、Ni、Cu、Sn、Sb、Ta、U、F、As、Mo、Cd和Hg。六枝六龙煤矿煤层中的大多数微量元素(Be、B、Sc、V、Cr、Co、Ni、Cu、Zn、Ga、 Se、Rb、Sr、Y、Zr、Nb、Sn、Cs、Ba、REE、Hf、Ta、Pb、Th和U)表现出铝硅酸盐亲和性,Hg、As和Mo主要赋存于硫化物中;织金凤凰山煤矿煤层中的大多数微量元素(Sc、 V、Cr、 Co、Ni、Zn、Ga、Rb、Sr、Zr、Nb、Sn、Ba、REE、Hf和Ta)表现出铝硅酸盐亲和性,Cu、As、Se、Sb、Pb和Hg主要赋存于硫化物中；织金文家坝煤矿煤层中的大多数微量元素(Be、Sc、V、Cr、Co、Ni、Ga、Rb、Sr、Zr、Nb、Sn、Ba、REE、Hf、Ta和W)表现出铝硅酸盐亲和性,Hg、Pb和Mo主要赋存于硫化物中。上述三个煤矿煤层中的Mn出现于碳酸盐矿物中。黔西煤中异常富集元素主要包括Ta、Nb、As、Hg、F和Mo。Nb和Ta主要赋存于铝硅酸盐矿物或重矿物,其异常富集区沿水城-紫云同沉积断裂分布,此位置与六枝-水城-带的三角洲朵体相重叠,此归因于龙潭组沉积期,北西-南东向展布的水城-紫云同沉积断裂为黔西地区北西方向碎屑物源的输入提供了便利的通道,碎屑物质沿此断裂搬运而进入沼泽;As、Hg、F和Mo主要赋存于硫化物中,其异常富集区主要分布于黔西南的兴义、兴仁、安龙和贞丰等地区,该区位于由北西-南东向的水城-紫云同沉积断裂、北东-南西向的师尊-贵阳断裂和册亨弧形断裂所夹持的近似三角区域,这些断裂为同期和后期流体活动和岩浆热液的活动提供了便利的通道。由此可见,构造背景决定了异常富集元素的分布范围。峨眉山玄武岩性质和物源供给强度是黔西煤中V、Cr、Co、Ni、Cu、Nb和Ta富集的主控因素；黔西煤中硫及亲硫化物元素的富集受控于峨眉山玄武岩性质、海水影响和还原条件的共同作用；黔西煤中异常富集的As、Hg、F和Mo受控于后期热液流体的控制。
[Abstract]:In this paper, based on the theory and method of coal chemistry, mineralogy and geochemistry, the coal chemistry, mineralogy and geochemistry of the upper two Longtan Formation coal in the upper two series are systematically studied, based on the summary of the sampling analysis of the key mining areas and the data of the exploration results and the published literature. The coal quality characteristics, mineralogical characteristics and geochemical characteristics of Qianxi coal, and discuss the distribution characteristics and genetic mechanism of abnormal enrichment elements. The main understanding is as follows: 1, coal chemical Qianxi coal is mainly characterized by low water content, low medium to medium ash and low middle volatile yield, high sulfur content coal as the characteristic. The average yield of coal ash in Qianxi is 23%, and by basin margin land The ash yield of the basin edge and basin center is increased by the influence of source debris and basin heart sea water intrusion. The ash yield is high to low high in the lower part of the Longtan Formation and the upper part of the middle and upper part of the basin. It corresponds to the trend of the Yu Hai plane ascending and descending, which reveals that the ash content is closely related to the change of sea level. The rate of transition from low and medium volatiles to low volatile, and then transition to low middle volatile yield is mainly affected by regional thermal metamorphism. The increase of the degree of metamorphism in central coal is related to the increase of overlying strata thickness in coal bearing strata. The sulfur content in coal is mainly pyrite sulfur. The sulfur content is increasing from North West to South East, and in turn from continental facies area. The sulfur content in the lower part of the Longtan Formation and the upper part of the Longtan Formation is high to low high, which is consistent with the trend of the sea level elevation drop and rise in the Longtan Formation Period of Qianxi, so the sulfur content in Qianxi coal is controlled by the change of Yu Hai plane.2, coal mine. The minerals in the coal are mainly quartz, pyrite and rectorite, kaolinite, illite and white iron ore, with a small amount of anatase, montmorillonite, plaster, palygorskite, ferric dolomite, chlorite, sodium feldspar, ferric alum, and four water white ferric alum, which are basically consistent with the distribution characteristics of quartz and sulfide in coal in the area previously published. Different geological factors have great differences in the mineral species and content of different coal mines in different mining areas or in the same mining area. In Zhijin Lantau Peak coal mine and Wen Jia dam coal mine, the research coal samples have very low volatile yield (8.1%), and there are three kinds of mineral assemblages related to the thermal metamorphism, that is, the combination of Rectorite + pyrite, kaolinite + Rectorite The combination of quartz + pyrite and quartz + rectorite. In the six branch of six Dragon coal mine, coal samples have low volatile yield (18.5%), quartz + kaolinite combination and quartz + illite + pyrite + white iron ore. In coal seam, quartz, illite, kaolinite, sulfide and anatase are close to the roof, and the floor or gangue layer is enriched. It is revealed that the supply intensity of the material source has an important control effect on it, and the carbonate minerals appear in the stratified samples with low content of the detrital minerals (illite and anatase), indicating that the detrital material is obstructed by the formation of the other rock, and that the rectorite is derived from the transformation of kaolinite to the rectorite in the coal metamorphic process and reveals that it is hot. The formation of the pyrite is controlled by the source strength of the source, the influence of the sea water and the pH conditions of the marshes. There are two types of illite in the coal seam, that is, the detrital illite and the same illite. The titanium content in the clastic illite is high, but the content of the titanium is very low; the rectorite exists in the way of fissure and cell filling. The chlorite and rectorite coexist in the fissures, and the pyrite is spherical polycrystalline strawberry pyrite, the cells fill pyrite, the radial pyrite crystal, the massive pyrite in the organic matrix, the form of its dispersed pyrite and the pyrite filling the fissure, and the first three modes of occurrence indicating the genesis of the pyrite. The latter three modes of occurrence indicate that they are secondary causes. Part of the iron sulfate minerals and illite coexist in the cell filling, which does not represent the syngenetic cause of the iron sulfate minerals, but the cells fill the oxide products of the pyrite. The penetration of the permeable channel leads to the oxidation of the previous pyrite, and the gypsum is also clustered around the cleat / fissure, which is the reaction product of calcite and sulphuric acid (sulfide oxidation). The genesis of the gypsum containing Si and A1 may be included with the aluminosilicate mineral (the size less than EDX beam size) of the fluid precipitated during the formation of the gypsum. In gypsum crystal, the constant elements of coal seam samples studied by.3 and coal geochemistry are mainly composed of SiO2, Al2O3 and Fe203. Except for the concentration of K20 in No. 3 coal and the mild enrichment of Ti02 in No. 3 coal of the coal mine of six branch and six Dragon coal mine, the content of the constant elements in the coal seam 7 of the Zhijin Wen Jia Ba coal mine is slightly enriched, and the content of the constant elements in the other coal seam is similar to the average of the Chinese coal. The average element of the Qianxi coal is similar to that of the Chinese coal, but the coal concentration in the Qianxi coal field is slightly enriched with CaO and MgO, and the coal mine of Xingyi coal is enriched with K2O. six branch and six Dragon coal mine 3 coal seams enriched Ta, Nb, V, Cr, Co, Cu, Sr, Nb and Ba, enrichment and enrichment of coal seam No. 23, Zhijin Lantau Peak coal mine And U, the coal seam No. 6 of Wen Jia Ba coal mine, Zhijin, enriched Ta, Li and No. 7 coal seams enriched Ta and Nb. The contents of other trace elements and Chinese coal trace elements are similar or loss. From the published statistics on coal in Qianxi, the main enrichment of V, Cu, Mo, Sb, Ta, U, As and depletion, the other trace elements are similar to or loss of the Chinese coal. Liupanshui coal field coal enriched Cu, Zn, Nb, and coal field coal enriched V, Cu, Nb, Mo, U and Ta in the coal field coal of the north of Guizhou. V, Cr, Co, Ni, Cu, Zn, Ga, Se, Rb, Sr, Y, exhibiting aluminum silicate affinity. The most trace elements (Be, Sc, V, Cr, Co, Ni, Ga, Rb, Sr, Zr, Nb, Sn, Nb, Ga, Rb, Zr, Nb, Ga, Rb, Sr, Zr, Nb) in the coal coal mine of the Wen Jia Ba coal mine are found in the sulphides. The three coal coal seams above appear in the carbonate minerals. The abnormally enriched elements in the coal of Qianxi are the main elements. Ta, Nb, As, Hg, F and Mo.Nb and Ta are mainly deposited in aluminosilicate minerals or heavy minerals, and their abnormal enrichment areas are distributed along the Shuicheng Ziyun synsedimentary fault. This position overlaps with the Delta Zone of the six branch - Shuicheng zone, which is attributable to the sedimentary period of the Longtan Formation, and the northwestern South East is distributed in the Shuicheng Ziyun synsedimentary fault to the North West of Qianxi region. As, Hg, F and Mo are mainly located in sulfides, and their abnormal enrichment areas are mainly distributed in Xingyi, Xingren, an dragon and Zhenfeng in southwestern Guizhou, and the area is located in the Shuicheng Ziyun synsedimentary fault from the North West to the East and north-east NW. The master - Guiyang fault and the approximate trigonometric zone held by the brotherhood arc fracture, which provide a convenient channel for the fluid activity and the activity of the magmatic hydrothermal fluid at the same time and later, can be seen that the tectonic setting determines the distribution of the abnormal enrichment elements. The properties of the Mount Emei basalt and the supply strength of the source are V, Cr, C in the coal. The main controlling factors of the enrichment of O, Ni, Cu, Nb and Ta; the accumulation of sulfur and sulphide elements in Qianxi coal are controlled by the properties of Mount Emei basalt, the influence of seawater and the reduction conditions, and the abnormal enrichment of As, Hg, F and Mo in the coal of Qianxi is controlled by the later hydrothermal fluid.
【学位授予单位】：中国地质大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P618.11

【相似文献】