高硫煤中硫的地质演化模式——以内蒙古乌达矿区为例  

Model of Sulphur Accumulation in the High-sulphur Coal——A Case Study from the Wuda Coalfield, Inner Mongolia

作　　者：代世峰[1] 任德贻[1] 唐跃刚[1] 王延斌[1] 李生盛[1] 

机构地区：[1]中国矿业大学煤炭资源教育部重点实验室,北京100083

出　　处：《地质论评》2001年第4期383-387,共5页Geological Review

基　　金：国家自然科学基金(编号40072054);煤炭科学基金(编号97地10205)

摘　　要：以内蒙古乌达矿区为例,通过对高硫煤9煤层中黄铁矿和有机硫同位素的测定(有机硫同位素δ^(34)S=-12.3‰～5.8‰,黄铁矿硫同位素δ^(34)S=-18.7‰～1.1‰),结合煤岩学特征的综合分析以及黄铁矿化菌落和蓝藻胶壳的发现,提出了高硫煤中疏的演化模式,认为高硫煤中主要来源的硫的同位素由于硫酸盐的异化细菌还原作用导致大规模分馏,使之趋于负值。在高硫煤形成过程中,黄铁矿和有机硫表现出形成初期Fe^(2+)和有机质对硫离子的争夺性、形成过程中在剖面上的层次性、阶段性和时间上的相向性。层次性和阶段性表现为沼泽体系对SO_4^(2-)和H_2S的开放程度及黄铁矿的形成对^(32)SO_4^(2-)的过滤性,相向性表现为泥炭聚积初期和晚期,Fe^(2+)和SO_4^(2-)对高硫煤形成做出了贡献,具有剖面上的对称特点。A Model of sulphur evolution in the high-sulphur coal is introduced in the paper to reflect the palaeo-envi-ronment during the coal accumulation based on isotopic determinations of the organic sulphur and pyrite ( δ34S of organic sulphur from - 12. 3‰ to 5. 8‰ and δ34S of pyritic sulphur from -18. 7‰ to 1. 1‰), in combi-naion with synthetic analysis of coal petrology and findings of pyritized rod-like bacteria and blue-green algae's gelationous sheath in the column sections of the No. 9 coal seam in the Wuda coalfield, Inner Mongolia, China. The model indicates that the sulphur isotopes, whose values tend to be negative owing to extensive fractionation caused by reduction of dissimilatory bacteria of sulphates. During the formation of the high-sulphur coal, Fe2+ and organic matter show an affinity with S2~ in the initial stage of pyrite and organic sulphur formation, the isotopic composition of sulphur shows layered variations from bottom to top in the coal seam, and the generation of sulphur in the coal reflects a reversed variation with that in the geological history. These characteristics reflect the open degree of SO42- and H2S in a system and filtration of 32SO42- owing to the pyrite formation, and the contributions of Fe2+ and SO2-4 to formation of the high-sulphur coal in the initial and late stages of peat accumulation, which shows a symmetry in the column section.

关 键 词：地质演化模式 高硫煤 硫同位素 乌达矿区 内蒙古 有机硫 黄铁矿 

分 类 号：P618.11[天文地球—矿床学]