太原西山煤田7号煤层古泥炭沼泽植物群落及其演替

PALAEOCOMMUNITY AND ITS SUCCESSION OF PEAT SWAMP OF NO.7 SEAM IN XISHAN COALFIELD

山西太原西山煤田斜道沟太原组７号煤层古泥炭沼泽植物群落由菌藻类、石松类、节蕨类、真蕨类、种子蕨类以及科达类等植物所组成。科达植物在群落中占据优势地位，鳞木和辉木为亚优势类群。科达植物的２个种Ｓｈａｎｘｉｏｘｙｌｏｎｓｉｎｅｎｓｅ和Ｐｅｎｎｓｙｌｖａｎｉｏｘｙｌｏｎｔｉａｎｉｉ很矮小，适合于在覆水较深、营养较贫乏的环境中生活。另１种科达植物Ｓｈａｎｘｉｏｘｙｌｏｎｔａｉｙｕａｎｅｎｓｅ可能生活于泥炭沼泽中地势较高的地方或泥炭沼泽的边缘。鳞木、封印木和芦木的生态解剖学特征表明它们都适合于在泥炭沼泽中生活．树蕨辉木可能生活于泥炭沼泽的边缘．７号煤层古泥炭沼泽植物群落经历了由早期的鳞木、辉木和科达Ｓｈａｎｘｉｏｘｙｌｏｎｔａｉｙｕａｎｅｎｓｅ占优势的植物群落，到中期的芦木类较占优势的植物群落以及晚期的矮小科达Ｓｈａｎｘｉｏｘｙｌｏｎｓｉｎｅｎｓｅ和Ｐｅｎｎｓｙｌｖａ－ｎｉｏｘｙｌｏｎｔｉａｎｉｉ占优势的植物群落这样１个演替过程，反映了泥炭沼泽覆水程度逐渐增强、营养状况渐趋贫乏的演化趋势。

The palaeocommunity of peat swamp of coal No. 7 seam in Xiedaogou, Xishan coalfield in Taiyuan, Shanxi consisted of fungi, algae, Lycopsida, Sphenopsida, ferns , Pteridospermopsida and Cordaitopsida. The dominant plants were Cordaitopsida,and subdominant plants were arborescent Lycopsida Lepidodendron, tree fern Psaronius and Cordaitopsida Shanxioxylon taiyuanense. Two species of Cordaitopsida ,Shanxioxylon sinense and Pennsylvanioxylon tianii,were small trees and they were adapted to growing in oligotrophic environment with deeper covering water. Shanxioxylon taiyuanense probably grew in higher place of peat swamp or along the fringe of the peat swamp. The ecological plant anatomical features of the arborescent Lycopsida (Lepidodendron and Sigillaria) and Calamites show that they were suitable for growing in the peat swamp. Tree fern Psaronius might grow along the fringe of the peat swamp. A succession of the community took place in the peat swamp of No. 7 seam, that is Lepidodendron ,Psaronius and Shanxioxylon taiyuanense were dominant in the early stage ,calamites were well developed in the middle stage and small trees of Cordaitopsida Shanxioxylon sinense and Pennsylvanioxylon tianii became dominant in the community in the later stage. This represents the trend of evolution, i. e.peat swamp was covered by deeper water and state of nutrition became worse and worse.