高级检索

三塘湖煤田西山窑组煤地球化学特征及沉积环境意义

Geochemical characteristics of coal and sedimentary environment significance in Xishanyao Formation of Santanghu Coalfield

  • 摘要: 为了查明新疆三塘湖煤田汉水泉矿区西山窑组煤中元素富集情况,通过分析元素表征指数对环境的指示作用,来揭示该煤组沉积环境变化特征,基于煤田地质学、地球化学等理论方法,通过低温灰化、ICP-MS等手段,得出煤中微量元素、稀土元素含量并对其进行分析。
    结果表明:该煤组元素V、Cu、As、Rb、Sr相对富集,稀土元素分布模式表明轻稀土(LREE)明显亏损,重稀土(HREE)相对富集,Ce负异常,Eu正异常。经低温灰化处理后稀土元素含量远高于未处理的,表明稀土元素大多赋存于有机质中。研究区煤层中V、Ga的富集与黏土矿物含量较高有关,Cu与黄铁矿相伴生,As元素主要以砷黄铁矿的形式存在。δEu、Sr/Ba、V/(V+Ni)、V/Cr、Ni/Co及S的含量总体上反映该区泥炭的沉积环境:主体为陆相淡水还原环境,局部为弱氧化环境;其中7、9、17、22号煤层处于氧化环境,8、13、14、15、18、19、20号煤层处于还原环境,垂向上呈氧化还原交替变化的古环境特征,推断三塘湖煤田西山窑组含煤岩系在沉积阶段主体上为湖侵过程,期间伴随多次小范围的湖侵-湖退过程。

     

    Abstract: In order to find out the enrichment of elements in Xishanyao Formation coal,Hanshuiquan mining area, Santanghu Coalfield, Xinjiang, the indication of element characterization index to the environmentis analyzed toreveal the characteristics of sedimentary environment change.Based on coalfield geology, geochemistry and other theoretical methods, with low temperature ashing, ICP-MS and other means, the content data of trace elements and rare earth elements in coal is obtained and analyzed.The results show that trace elements V, Cu, As, Rb and Sr are relatively enriched in coal. The distribution forms of rare earth elements show that the light rare earth element (LREE) is obviously deficit while the heavy rare earth element (HREE)is relatively enriched and it also indicates that Ce shows negative anomaly and Eu appears to positive anomaly. The content of rare earth elements after low temperature ash is much higher than that of untreated, which indicates that most of the rare earth elements exist in organic matter.The enrichment of V and Ga in coal seams in the study area is related to the high content of clay minerals; Cu is associated with pyrite; As mainly exists in the form of arsenopyrite. The contents of δEu, Sr/Ba, V(V+Ni), V/Cr, Ni/Co and S generally reflect that the sedimentary environment in the study area is continental fresh water reduction environment and partly weak oxidation environment. No.7, 9, 17, 22 coal seams are in Paleo-oxidizing environment, No.8, 13, 14, 15, 18, 19, 20 coal seams are in a reducing environment and Paleo-environment is characterized by alternating redox reduction in vertical direction. It is inferred that the coal-bearing rock series is a lake transgression process in the main body of sedimentary stage of Xishanyao Formation in Santanghu Coalfield, accompanied by many small-scale lake transgression-lake regression processes.

     

/

返回文章
返回