摘要
采用XRF、ICP-MS等技术测定了湘中南地区二叠系龙潭组5个煤层煤样的主量元素与稀土元素含量。对主量元素和稀土元素地球化学特征、稀土元素分配模式、赋存状态及来源、成煤环境等的研究表明,湘中南煤中∑REE变化于10.42×10~(-6)~122.73×10~(-6),平均为63.67×10~(-6),高于世界煤均值;LREE/HREE变化于4.26~11.63,平均为7.35,具有弱Ce负异常(δCe:0.85~1.08)和显著Eu负异常(δEu:0.55~0.71),表明成煤环境为受海水影响较弱的还原环境;∑REE与煤灰分产率、Si、Al、Ca等呈正相关关系,三角端元图解显示靠近陆源区的泥炭沼泽覆水程度较浅,碎屑物质注入较多,造成煤中稀土元素含量高;湘中南地区龙潭组煤与基底前寒武纪板岩等具有相似的稀土元素分配曲线,呈现继承性的关系。
The XRF and ICP-MS methods were used to determine the abundances of major elements and REE of five samples of Permian Longtan Formation coals from south central Hu'nan province. The detailed studies of major elements and REE geochemistry characteristics, chondrite-normalized REE distribution patterns, occurrence mode, source and coal-accumulating environments show that the concentration of REEs ranges from 10.42×10~(-6) to 122.73×10~(-6) with an average value of 63.67×10~(-6), which are higher than world coal on average. LREE/HREE ranges from 4.26 to 11.63 with an average value of 7.35. Moderate Eu negative anomaly(δEu: from 0.55 to 0.71) and weak Ce anomaly(δCe: from 0.85 to 1.08) were observed for all coal samples, which suggest reducing environment with weak influence of seawater. The positive and significant correlations of ∑REE vs. ash yield, Si, Al, Ca were seen in bivariate plot. The triangular diagram analysis shows that the Permian Longtan Formation coals formed in terrigenous detrital-dominated coal-accumulating swamp near provenance with shallow water and were characterized by higher REEs content. The REEs contents and distribution patterns of Permian Longtan Formation coal samples are similar to those of Precambrian basement slate and show an inheritance relationship.
引文
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