胜利煤田胜利组褐煤地球化学特征及古环境地质意义  

Geochemical characteristics of lignite from Shengli Formation and Paleo-environmental geological significance in Shengli Coalfield

作　　者：董振国 赵伟 郭军军 肖兵 李斌 任玺宁 崔春兰 DONG Zhenguo;ZHAO Wei;GUO Junjun;XIAO Bing;LI Bin;REN Xining;CUI Chunlan(National Energy Investment Group Co.,Ltd.,Beijing 102211,China;Shenhua Nortel Shengli Energy Co.,Ltd.,Xilinhot 026099,China;Hanjiang Normal College,Chaozhou 521041,China)

机构地区：[1]国家能源投资集团有限责任公司,北京102211 [2]神华北电胜利能源有限责任公司,内蒙古锡林浩特026099 [3]韩江师范学院,广东潮州521041

出　　处：《煤炭科学技术》2020年第11期172-181,共10页Coal Science and Technology

基　　金：国家重点研发计划资助项目(2016YFC0501102-04)。

摘　　要：早白垩世胜利组是内蒙古东部胜利煤田的主要含煤地层,为了查明胜利组煤层煤岩元素特征及沉积环境,为煤炭开采提供地质依据,系统地采集胜利组煤岩样品开展了煤岩物理化学、元素含量等的测试分析,基于元素地球化学等理论方法,对胜利组沉积时的沉积相、古盐度、古气候特征和古生产力条件进行综合研究。研究结果表明:胜利组煤质为褐黑色的褐煤,以亮煤和暗煤为主,镜煤最大反射率Ro=0.2%~0.5%,各煤层具有中高含水(Mad=12.12%)、低中灰分(Ad=18.34%)、高挥发分(Vdaf=45.55%)、特低固定碳(FCad=24%)、低中硫(St.d=1.39%)、中高热值(Qnet=22.19 MJ/kg)的工艺性能;常量元素成分以Si、Fe、Al为主,少量Ca、Mg等,灰成分指数较低(3.29),反映了胜利煤田成煤期为低位泥炭沼泽环境,还原性较强;MgO/Al2O3比值中等(18.78)和CaO/(MgO×Al2O3)比值较高(0.15),表示古气候较干燥,蒸发量较大,水体含盐度较高,基本属于咸水环境;微量元素V/(V+Ni)、V/Cr、Ni/Co、U/Th、V/Sc等比值分别为0.83、2.14、2.15、0.87、10.06,结合U元素丰度为0.98μg/g,判断该煤田煤层底层水环境以长期缺氧还原条件为主,并伴随着多次短暂的富氧;Sr/Ba和Th/U判断胜利组沉积水体为半咸水—咸水环境,在垂向上,随湖盆的逐渐萎缩和蒸发量变大,向上泥炭沼泽覆水变浅,水体含盐度有所增加;Mo、Ba、Cu、Ni等丰度无明显的富集现象,推测当时古生产力中等,表现为中位泥炭沼泽,为有利的成煤和聚煤沉积环境。The Early Cretaceous Shengli Formation is the main coal-bearing strata in the Shengli Coalfield in eastern Inner Mongolia.In order to find out the elemental characteristics of coal and sedimentary environment of coal seams from Shengli Formation and provide a geological basis for coal mining,coal and rock samples from Shengli Formation were systematically collected.Tests and analyses of petrography,physical chemistry,geochemistry,etc.were carried out.Based on theoretical methods such as element geochemistry,the sedimentary facies,Paleo-salinity,Paleo-climatic characteristics and Paleoproductivity of the Shengli Formation were analyzed.The results show that the sample from the Shengli Formation is brown-black lignite,mainly containing vitrain and durain.The maximum reflectance(Ro)of vitrinite is 0.2%to 0.5%.The moisture content of each coal seam is medium to high(Mad=12.12%),ash yield of each coal seam is low to medium(Ad,18.34%),volatile matter yield of each coal seam is high(Vdaf=45.55%),fixed carbon yield of each coal seam is extra-low(FCad=24%),the total sulfur content of each coal seam is low to medium(St.d=1.39%),and calorific value of each coal seam is medium to high(Qnet=22.19 MJ/kg).The major elements of the samples are mainly Si,Fe,and Al,a small amount of Ca,Mg,etc.,and the ash composition index is low(mean value is 3.29),which indicates that the coal formation period is a low-level peat swamp environment,with relatively low reduction.The ratio of MgO/Al2O3 is medium(18.78),and the ratio of CaO/(MgO×Al2O3)is high(0.15),indicating that the Paleo-climate is relatively dry,the evaporation is large,and the water body has high salinity,which is basically a salt water environment.The ratios of trace elements V/(V+Ni),V/Cr,Ni/Co,U/Th,V/Sc are 0.83,2.14,2.15,0.87,10.06,respectively.Combined with U abundance of 0.98μg/g,it is judged that the bottom water environment of the study area is dominated by long-term hypoxic reduction conditions,accompanied by many short-term periods of oxygen enrichment.The ratio of

关 键 词：白垩系下统 煤岩煤质 元素分析 沉积环境 

分 类 号：P595[天文地球—地球化学] P531[天文地球—地质学]