Causes of anomaly of rare earth elements of seam 2 of Yan’an Formation in the northern margin of Ordos basin and its geological significance

Authors

YANG Yi, Shandong Key Laboratory of Depositional Mineralization and Sedimentary Minerals, Shandong University of Science and Technology, Qingdao 266590, China;Anhui Nuclear Exploration Technology Central Institute, Wuhu 241003, China
LYU Dawei, Shandong Key Laboratory of Depositional Mineralization and Sedimentary Minerals, Shandong University of Science and Technology, Qingdao 266590, ChinaFollow
ZHANG Jianqiang, General Prospecting Institute, China National Administration of Coal Geology, Beijing 100039, China
WU Dun, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China

Abstract

The cause of rare earth elements(REE) anomalies in No.2 coal seam of the Yan’an Formation in the northern margin of the Ordos basin has been controversial. This paper takes Dahaize coal mine, Yulin area with well developed No.2 coal as an example to analyze REE, mineralogical characteristics of coal and partings, and to reveal the causes of anomaly of REE by Inductive Coupled Plasma Mass Spectrometry(ICP-MS) and Scanning Electron Microscopy(SEM). The results show that the total rare earth element(∑REE) concentration in the coal samples ranges from 3.71 to 46.21 μg/g. Light rare earths elements(LREE, La-Eu) are more abundant than heavy rare earth elements(HREE, Gd-Lu). The distribution patterns of their normalization show that a few of samples have positive anomalies. Samples with high REE content and samples with positive Eu anomalies mainly appeared in the analyzed coal seam close to the partings. It is indicated that the distribution of REE in coal is affected by its partings. There are many zircons, apatites, sanidines and anatase with better crystal form found in the partings, which are direct evidence of the volcanic activity during the peat formation. This suggests that there was a volcanic activity during the No.2 peat formation of the Yan’an Formation in Ordos basin. The volcanic ash fallen over and covered the swamp and affected the coal accumulation and the abnormal distribution of REE in the coal. The results explain the reason of REE anomaly in the coal and provide data support or theoretical basis for the future industrial use of REE in the coal in this area.

Keywords

rare earth elements, mineralogy, Eu abnormity, volcanic activity, Ordos basin

DOI

10.3969/j.issn.1001-1986.2020.02.013

Recommended Citation

YANG Yi, LYU Dawei, ZHANG Jianqiang, et al. (2020) "Causes of anomaly of rare earth elements of seam 2 of Yan’an Formation in the northern margin of Ordos basin and its geological significance," Coal Geology & Exploration: Vol. 48: Iss. 2, Article 14.
DOI: 10.3969/j.issn.1001-1986.2020.02.013
Available at: https://cge.researchcommons.org/journal/vol48/iss2/14

Reference

[1] 王东东,邵龙义,李智学,等. 鄂尔多斯盆地延安组层序地层格架与煤层形成[J]. 吉林大学学报(地球科学版),2013,43(6):1726-1739. WANG Dongdong,SHAO Longyi,LI Zhixue,et al. Sequence stratigraphic framework and coal formation of Yan'an Formation in Ordos basin[J]. Journal of Jilin University(Earth Science Edition),2013,43(6):1726-1739.

[2] 王双明. 鄂尔多斯盆地聚煤规律及煤炭资源评价[M]. 北京:煤炭工业出版社,1996:436-437. WANG Shuangming. Coal accumulation law and coal resource evaluation in Ordos basin[M]. Beijing:Coal Industry Press,1996:436-437.

[3] 黄迪颖. 中国侏罗纪综合地层和时间框架[J]. 中国科学:地球科学,2019,49(1):227-256. HUANG Diying. Jurassic integrated stratigraphy and time frame in China[J]. Science China:Earth Science,49(1):227-256.

[4] 邵靖邦,曾凡桂,王宇林,等. 平庄煤田煤中稀土元素地球化学特征[J]. 煤田地质与勘探,1997,25(4):13-16. SHAO Jingbang,ZENG Fangui,WANG Yulin,et al. The geochemistry of rare earth element in brown coal of Pingzhuang coalfield,Inner Monglia[J]. Coal Geology & Exploration,1997,25(4):13-16.

[5] DAI Shifeng,LI Dan,CHOU Chenlin,et al. Mineralogy and geochemistry of boehmite-rich coals:New insights from the Haerwusu surface mine,Jungar coalfield,Inner Mongolia,China[J]. International Journal of Coal Geology,2008,74(3/4):185-202.

[6] FINKELMAN R B. Modes of occurrence of environmentally sensitive trace elements in coal[J]. Fuel and Energy Abstracts,1997,38(3):135.

[7] HOWER J C,EBLE C F,DAI Shifeng,et al. Distribution of rare earth elements in eastern Kentucky coals:Indicators of multiple modes of enrichment[J]. International Journal of Coal Geology,2016,160/161:73-81.

[8] 刘东娜,周安朝,刘建权. 东胜煤田侏罗系延安组煤中稀土元素地球化学特征[J]. 中国煤田地质,2007,19(2):20-22. LIU Dongna,ZHOU Anchao,LIU Jianquan. Geochemical characteristics of rare earth elements in Yan'an Formation,Jurassic system,Dongsheng coalfield[J]. Coal Geology of China,2007,19(2):20-22.

[9] ZHAO Fenghua,CONG Zhiyuan,PENG Suping,et al. Geochemical characteristics of REE in Jurassic coal of Yan'an Formation from Dongsheng coalfield[J]. Journal of China University of Mining & Technology(English Edition),2002,12(2):138-142.

[10] WANG Xiaomei,JIAO Yangquan,WU Liqun,et al. Rare earth element geochemistry and fractionation in Jurassic coal from Dongsheng-Shenmu area,Ordos basin[J]. Fuel,2014,136:233-239.

[11] ZHAO Cunliang,DUAN Dujuan,LI Yanheng,et al. Rare earth elements in No.2 coal of Huangling mine,Huanglong coalfield,China[J]. Energy Exploration & Exploitation,2012,30(5):803-818.

[12] WANG Xibo. Petrology and geochemistry of the Jurassic coals in southwestern Ordos basin,China[J]. Energy Exploration & Exploitation,2010,28(6):513-530.

[13] 张泓,何宗莲,晋香兰,等. 鄂尔多斯盆地构造演化与成煤作用:1:500000鄂尔多斯煤盆地地质构造图简要说明[M]. 北京:地质出版社,2005:49-53. ZHANG Hong,HE Zonglian,JIN Xianglan,et al. Tectonic evolution and coal accumulation of the Ordos basin:A brief explanation of the geological tectonic map of the Ordos coal basin(with scale of 1:50000)[M]. Beijing:Geological Publish House,2005:49-53.

[14] 刘池洋,赵红格,桂小军,等. 鄂尔多斯盆地演化:改造的时空坐标及其成藏(矿)响应[J]. 地质学报,2006,80(5):617-637. LIU Chiyang,ZHAO Hongge,GUI Xiaojun,et al. Space-time coordinate of the ecolution and reformation and mineralization response in Ordos basin[J]. Acta Geologica Sinica,2006,80(5):617-638.

[15] ZHANG Chuang,YI Chao,DONG Qian,et al. Geological and geochronological evidence for the effect of Paleogene and Miocene uplift of the northern Ordos basin on the formation of the Dongsheng uranium district,China[J]. Journal of Geodynamics,2018,114:1-18.

[16] 葛道凯,杨起,付泽明,等. 陕西榆林侏罗纪煤系基底古侵蚀面的地貌特征及其对富县组沉积作用的控制[J]. 沉积学报,1991,9(3):65-73. GE Daokai,YANG Qi,FU Zeming,et al. The geomorphologic features of basement of Jurassic coal measures and its control on the sedimentation of Fuxian Formation in Yulin,Shaanxi Province[J]. Acta Sedimentologica Sinica,1991,9(3):65-73.

[17] 张天福,孙立新,张云,等. 鄂尔多斯盆地北缘侏罗纪延安组、直罗组泥岩微量、稀土元素地球化学特征及其古沉积环境意义[J]. 地质学报,2016,90(12):3454-3472. ZHANG Tianfu,SUN Lixin,ZHANG Yun,et al. Geochemical characteristics of trace elements and rare earth elements in the Jurassic Yan'an Formation and Zhiluo Formation in the northern margin of the Ordos basin and their paleoenvironmental significance[J]. Acta Geologica Sinica,2016,90(12):3454-3472.

[18] YANG Renchao,HAN Zuozhen,LI Zengxue,et al. Base-level cycles and Episodic coal accumulation:Case study of Dongsheng coalfield in Ordos basin[J]. Journal of China University of Mining & Technology(English Edition),2006,16(4):439-442.

[19] 刘颖,刘海臣,李献华. 用ICP-MS准确测定岩石样品中的40余种微量元素[J]. 地球化学,1996,25(6):552-558. LIU Ying,LIU Haichen,LI Xianhua. Accurate determination of more than 40 trace elements in rock samples by ICP-MS[J]. Geochimica,1996,25(6):552-558.

[20] DAI Shifeng,GRAHAM I T,WARD C R. A review of anomalous rare earth elements and yttrium in coal[J]. International Journal of Coal Geology,2016,159:82-95.

[21] Taylor S R,McLennan S M. The continental crust:Its composition and evolution[M]. London:Blackwel,1985:312.

[22] Ketris M P,Yudovich Y E. Estimations of clarkes for Carbonaceous biolithes:World averages for trace element contents in black shales and coals[J]. International Journal of Coal Geology,2009,78(2):135-148.

[23] SPEARS D A. The origin of tonsteins,an overview,and links with seatearths,fireclays and fragmental clay rocks[J]. International Journal of Coal Geology,2012,94:22-31.

[24] DAI Shifeng,LUO Yangbin,SEREDIN V V,et al. Revisiting the Late Permian coal from the Huayingshan,Sichuan,southwestern China:Enrichment and occurrence modes of minerals and trace elements[J]. International Journal of Coal Geology,2014,122:110-128.

[25] DAI Shifeng,WARD C R,GRAHAM I T. et al. Altered volcanic ashes in coal and coal-bearing sequences:A review of their nature and significance[J]. Earth Science Reviews,2017,175:44-74.

[26] 郑翻身,康屹青,康红在,等. 鄂尔多斯古陆核内部中生代晚期火山岩的发现及其地质意义[J]. 地质力学学报,2009,15(1):69-76. Zheng Fanshen,Kang Yiqing,Kang Hongzai,et al. Discovery and geological significance of late Mesozoic volcanic rocks in the ancient continental core of Ordos[J]. Journal of Geomechanics,2009,15(1):69-76.

[27] SEREDIN V V,DAI Shifeng. Coal deposits as potential alternative sources for lanthanides and yttrium[J]. International Journal of Coal Geology,2012,94:67-93.

[28] 伊海生,林金辉,赵西西,等. 西藏高原沱沱河盆地渐新世-中新世湖相碳酸盐岩稀土元素地球化学特征与正铕异常成因初探[J]. 沉积学报,2008,26(1):1-10. YIN Haisheng,LIN Jinhui,ZHAO Xixi,et al. Geochemistry of rare earth elements and origin of positive europium anomaly in Miocene-Oligocene lacustrine carbonates from Tuotuohe basin of Tibetan plateau[J]. Acta Sedimentologica Sinica,2008,26(1):1-10.

[29] 杜芳鹏. 鄂尔多斯盆地延安组煤岩学及煤元素地球化学特征[D]. 西安:西北大学,2019. DU Fangpeng. Petrological and element geochemical characteristics of the Yan'an coals in Ordos basin[D]. Xi'an:Northwest University,2019.

[30] 吴斌. 鄂尔多斯盆地东北部中侏罗世古环境古气候研究[D]. 成都:成都理工大学,2018. WU Bin. Paleoenvoironment and paleoclimate of the Middle Jurassic in northeastern of Ordos basin[D]. Chengdu:Chengdu University of Technology,2018.