葛万菌(Girvanella)是由一个相互串联着的细胞列和外部包绕的多糖质黏性胶鞘组成的蓝细菌化石，是豫西寒武系微生物岩中最常见的钙化微生物。葛万菌丝状体在不同的微生物岩中具有不同的排列方式。潮间带环境中的叠层石其葛万菌主要发育在暗色纹层中，丝状体呈规则的水平状分布。在低能的鲕粒滩滩间或滩后洼地环境中形成的核形石形态及圈层结构均不规则，葛万菌丝状体在其核心和暗色纹层中整体表现为不规则的密集缠绕状；高能鲕粒滩环境中的核形石形态浑圆，圈层结构规则，葛万菌丝状体在核形石暗色纹层中多沿切线方向分布。凝块石形成于台地鲕粒滩滩间局限海环境中，葛万菌丝状体相互交织成不规则团块状发育在凝块中。巨鲕形成于台地鲕粒滩滩间海环境，葛万菌丝状体在内圈层呈密集缠绕状分布，在外圈层则沿切线方向展布。虽然葛万菌群的排列方式在不同微生物岩中有所不同，但是单个葛万菌丝状体的特征相似。在偏光显微镜下，葛万菌丝状体呈略弯曲的无分枝、不分节、细长管状，相互缠绕叠覆；单管由深灰色的管壁(胶鞘)和中间明亮的管芯(细胞列)组成。在电子显微镜下，葛万菌的管壁由直径1—2μm 沿径向放射排列的粒状或短柱状方解石组成，为葛万菌光合作用诱导产生的生物矿物；管芯直径10—20μm，长度50—200μm 不等，由圆柱状方解石组成，为成岩期重结晶所致。根据葛万菌的显微结构，结合现代管状蓝细菌的特征，葛万菌由短杆状细胞而非球状细胞组成，其结构应为由短杆状细胞组成的细胞列、细胞壁和细胞外的胶鞘(EPS)。

Girvanella is a kind of cyanobacterial fossil with interconnected cell row and enveloping polysaccharide mucilaginous sheaths and is the most common calcified microbes in Cambrian microbialites of western Henan． Girvanella filaments display different distributions in different microbialites． The filaments in stromatolite of intertidal flat environment mainly occur in dark laminations and display as a regular horizontal distribution．The oncoids in low-energy coastal oolitic inter-shoal or back-shoal environments are dominated by irregular shape and cortex stru-ctures．Girvanella filaments are mainly irregular densely winding in nuclei and dark cortex of the oncoids．The oncoids in high-energy oolitic shoal environments have a round shape and regular cortex structures in which Girvanellafilaments are distributed in the dark cortex of the oncoids along the tangent direction． The thrombolites were formed in oolitic inter-shoal of restricted platform environments in which Girvanella filaments are mainly densely winding，being intertwined with each other with irregular distribution in the clots．The giant ooids were preserved in oolitic shoal of open platform environments in which Girvanella filaments appear as densely winding in inner cortex and as the tangent direction in the outer cortex．Each individual tube of Girvanellafilament display similar features although Girvanellafilaments have the different distributions in different micro-bialites．Each individual tube consists of a dark grey tube wall(sheath)and bright tube core(cell row)under polarizing microscope．Viewed under electronic microscopy，the tube wall of Girvanella consists of radial-arrayed granular or short columnar calcites which have a diameter of 1-2μm and are considered to be biominerals induced by photosynthesis of Girvanella．The tube core is made up of cylindrical calcites with the diameter of 10-20μm and the variation length of 50-200μm，which are the products of recrystallization during diagenesis． According to the microstructure of Girvanella in combination to the features of modern tubular cyanobacteria，Girvanellais made up of short rod cells instead of coccoid cells．Its microstructure includes strands of short rod cells attached end-to-end，cell walls and extracellular sheaths(EPS)．

国家自然科学基金项目(41472083)资助