贵州晚二叠世煤中硫同位素的组成特征

SULFUR ISOTOPIC COMPOSITION OF LATE PERMIAN COAL FROM GUIZHOU PROVINCE

报道了贵州主要开采矿山晚二叠世煤中不同形态硫的同位素组成特征。形成于海水影响较小环境中的煤以低的硫含量 ,偏正的δ34S值为特点 ;形成于海相或受海水影响较大的环境中的煤 ,则具有高的硫含量和偏负的δ34S值 ;在高硫含量的煤中 ,有机硫和无机硫具有弱的相关性 ,可能它们具有一致的来源 ;煤中有机硫的同位素组成对成煤环境是灵敏的 ,可作为成煤环境划分指标 ,根据有机硫含量和同位素组成 ,可分出海水对煤层的影响程度。

In Guizhou Province, the Late Permian coal was formed in the complex marine\|continental alternative zones. The total sulfur contents of main coal seams lie between 0.34 wt% and 9.16 wt%, with an average of 1.86 wt%. Except the Panxian coalfield, the other coalfields are characterized by high\|sulfur coal in which the total sulfur content is larger than 1.0 wt%. Different coal beds formed in different coal\|forming environments have distinctive sulfur contents and sulfur isotope values. The coal beds formed in freshwater swamps or in swamps, lightly influenced by sea water are characterized by low total sulfur contents and more positive δ\{\}\+\{34\}S values, with organic sulfur being the major sulfur species in the coal. On the contrast, high total sulfur contents and more negative δ\{\}\+\{34\}S values are produced in coal beds formed in marine and brackish swamps. In the high\|sulfur coal, there is a weak correlation between the δ\{\}\+\{34\}S values of organic sulfur and those of pyritic sulfur. This perhaps suggests that they have a common origin. The δ\{\}\+\{34\}S values of organic sulfur are negative as compared with the results of global coal. The reason perhaps is that there occurred secondary sulfur incorporation. It is found that the δ\{\}\+\{34\}S values of organic sulfur are helpful for determining the coal\|forming environment. Based on the δ\{\}\+\{34\}S values of organic sulfur, we can determine how the coal beds were influenced by sea water.\;