赣北前震旦纪微古植物群组合特征及地质意义

THE COMPOSITE FEATURES AND GEOLOGI-CAL SIGNIFICANCE OF PRESINIAN MICRO-PALEO-BOTANIC GROUP IN NORTH JIANGXI

在赣北前寒武纪变质地层中，发现了三套微古植物群。每套微古植物群的种属数量、所占比例、膜壳轮廓形态、纹饰结构、个体大小等组合特征，均有着显著的差异。第一套微古植物群组合最为原始，所代表的地层时代属早元古代晚期。第二套微古植物群组合比第一套演化程度较高，所代表的地层时代属中元古代。第三套微古植物群组合的演化程度最高，所代表的地层属晚元古代早期。

Three suits of micro-Paleobotanic group have been discovered inPrecambrian metamorphic terrance of North Jiangxi. There exist obvi-ous differences in the aspects of composite features,such as number ofspecies, proportion, form of membrane crustle configuration’ lamina-tion texture and zooid scale, etc in each suit of micropaleobotanicgroup. The first suit of micropaleobotanic group composite is the mostprimary, the representative stratigraphic era belongs to the later stageof early Preterozoic era, while the evolution degree of the second oneis more than the first one, the representative stratigraphic era belongsto the middle Preterozoic era. But the third one is the most intensive,its age belongs to the early stage of later Preterozoic era。