【摘要】 鲁西地区仙人洞剖面寒武系出露连续且沉积现象丰富,芙蓉统凤山组中部发育大型柱状叠层石。在层序地层框架下,基于野外观察,研究大型柱状叠层石的沉积特征。结果表明:寒武系凤山组大型柱状叠层石宏观上呈局部集中产出,柱状体边界清晰,纹层精美,横截面呈圆饼状,相对较大的柱状体直径代表华北地台寒武系叠层石的特殊类型。凤山组叠层石主要由致密泥晶、微亮晶构成,内部可见白云石、生物碎屑、黄铁矿颗粒;在柱状叠层石中可见大量保存精美的葛万菌(Girvanella)、胞网菌(Bacinella)等钙化微生物化石。凤山组大型柱状叠层石的建造者是以蓝细菌为主导的光合作用微生物席。特殊不规则网状物中的钙化丝状体及零星分散的黄铁矿颗粒,指示在大型柱状叠层石形成过程中微生物席内部存在复杂的微生物新陈代谢活动。仙人洞剖面凤山组大型柱状叠层石的发现既为寒武系叠层石研究提供典型实例,也为显生宙第一幕蓝细菌钙化作用发生期提供重要的岩石记录。更多还原

【Abstract】 The Xianrendong Section of Western Shandong Area is rich in Cambrian outcropping and sedimentation.Based on field observation and lab analysis,the sedimentary characteristics of stromatolites were studied under the framework of sequence stratigraphy.Some investigations showed that the large columnar stromatolites in Fengshan Formation are locally concentrated macroscopically,clear border of the column,fine lamination,and rounded cross-sections,its relatively large column diameter represents a special type of Cambrian stromatolites in North China Platform.The stromatolites in Fengshan Formation are mainly composed of dense micrite and microspar and dolomite,bioclastics and pyrite particles can be seen inside.Besides,a large number of well-preserved calcified microorganism fossils such as Girvanellaand Bacinellacan be found in the main body of stromatolites,which demonstrated the large columnar stromatolites in Xianrendong Section of Cambrian Fengshan Formation were constructed by photosynthetic microbial mats led by cyanobacteria.And calcified filaments in a particularly irregular network and scattered pyrite particles indicate that there are complex microbial metabolic activities in the mat during the formation of large columnar stromatolites.Therefore,the discovery of large columnar stromatolites in Xianrendong Section of Fengshan Formation provides a typical example for the study of Cambrian stromatolites and an important rock record for the first episode of phanerozoic cyanobacteria calcification.更多还原