河北庞家堡长城群微生物席群落与相关的沉积环境

MICROBIAL MAT COMMUNITIES AND RELATED SEDIMENTARY-GEOCHEMICAL ASPECTS OF THE MESOPROTEROZOIC CHANGCHENG GROUP,PANGJIAPU,HEBEI,NORTH CHINA

本文分析、描述了保存于河北庞家堡长城群团山子组和高于庄组燧石白云岩中的８个不同类型的微生物群落：Ｍｙｘｏｃｏｃｃｏｉｄｅｓ－Ｓｉｐｈｏｎｏｐｈｙｃｕｓ席群落（Ｍ１），Ｇｌｏｅｏｄｉｎｉｏｐｏｓｉｓ－Ｓｉｐｈｏｎｏｐｈｙｃｕｓ席群落（Ｍ２），Ｃｏｎｉｕｎｃｔｉｏｐｈｙｃｕｓ－Ｓｉｐｈｏｎｏｐｈｙｃｕｓ席群落（Ｍ３），Ｎａｎｏｃｏｃｃｕｓ席群落（Ｍ４），Ｅｏｅｎｔｏｐｈｙｓａｌｉｓ席群落（Ｍ５），Ｅｏｍｙｃｅｔｏｐｓｉｓ－ｃｏｃｃｏｉｄｂａｃｔｅｒｉａ席群落（Ｍ６），Ｓｉｐｈｏｎｏｐｈｙｃｕｓ席群落（Ｍ７）以及ｍｉｃｒｏｓｔｒｏｍａｔｏｌｉｔｅ－Ｎａｎｏｃｏｃｃｕｓ席群落（Ｍ８）。分析比较了微生物席群落的生物组成、席形态和结构，以及沉积－埋葬学特征。分析结果表明，不同类型的微生物席群落生存于不同的生境，席群落的变化可能反映环境的差异。同时，本文对包括８类微生物席群落和４类叠层石在内的团山子组与高于庄组（１－４段）不同层位的碳酸盐岩样品，进行了岩石化学分析。结果表明岩石中稀土元素和某些稀少元素含量的异常有指示沉积环境的意义；含有不同类型的微生物席群落和叠层石碳酸盐岩的稀土元素和某些稀少元素（如Ｌａ，Ｃｅ，Ｍｎ，Ｂ?

Here described are microbial mat communities with wellpreserved remains of mat-building organisms found from the Tuanshanzi and Gaoyuzhuang Formations in the Pangjiapu area (Hebei Province, China), including 8 types, which are Myxococcoides-Siphonophycus Community (M1), Gloeodiniopsis-Siphonophycus Community (M2), Coniunctiophycus-Siphonophycus Community (M3) ,Nanococcus Community (M4), Eoentophysalis Community (M5), Eomycetopsiscoccoid bacterium Community (M6), Siphonophycus Community (M7) and microstromatoliteNanococcus Community (M8). A comparative study on the taxonomic composition and taphonomical conditions of these mat-communities, combined with sedimentological analysis on the mat-hosting rocks, indicates that the composition and microstructure of the mats might reflect the properties of the mat-habitats. Geochemical analyses on the samples of the carbonate rocks (including mat-hosting rocks) from the two formations imply that the anomalies of rare earth elements (REE) and some rare elements such as La, Ce, Mn and Ba might serve as indications for the sedimentary environments. The significant difference in content of some elements between the samples of different mat-hosting rocks and stromatolites might reflect both biological and sedimentary characteristics.