摘要
Based on detailed observation by scanning electron microscope(SEM),we reported a discovery that bacterial fossils may occur in the siliceous shale of the early Cambrian black rock series in the Songlin area,Guizhou Province,SW China.They are 200~500 nm in diameters and vary in shapes,characterized by the size and shape of bacteria,high in total organic carbon(TOC),and phosphorus present in most bacteria.In comparison with the organism with similar morphology that has been reported previously,it is concluded that the fossils discovered may be the protogenetic microbioids with typical biological structure of bacteria and is called bacteria-like fossils in this study.These fossils occur mainly in surfaces of quartz grains,inter-grains and even within the quartz grains.Based on the previous simulation experiment,it can be assumed that bacteria may have played an important role in precipitation of quartz grains.The result in this study may provide new microscopic information for understanding the formation of siliceous rocks.