湖南台地泥盆纪末绝灭事件后的微生物沉积  

Microbial Sediments Occurring after the End-Devonian Extinction Event on the Hunan Platform

作　　者：侯鸿飞[1] 周怀玲 刘建波[3] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]广西地质调查研究院,南宁530023 [3]北京大学地球科学系,北京100037

出　　处：《地质学报》2011年第1期145-156,共12页Acta Geologica Sinica

基　　金：中国科学技术部<中国地层立典剖面及若干断代全球界线层型>项目(编号2006FY120300);中国地质调查组局<中国主要断代地层建阶研究>专项资助的成果

摘　　要：湖南中南部浅水碳酸岩台地,泥盆系顶部假整合面之上,石炭纪海进最早期,相当四射珊瑚Cystophrentis-Uralinia间隔带和单房室有孔虫带的层位,普遍发育厚度不等(7～30m)的微生物沉积。宏观上为条带状或斑块、瘤状构造,大部分由核形石组成,局部发育凝块构造内碎屑。它们均属微生物成因,代表汉根卑尔格绝灭事件后(接近泥盆-石炭系界线)的劫后产物,和北美奥陶纪末,特提斯、泛太平洋二叠纪末灭亡事件后的微生物沉积类似。据此表明,紧随生物绝灭事件后微生物沉积的再现并伴随生物多样性的降低,可能是生物复苏开始前的普遍规律。这一成果对研究集群绝灭后海洋生态系统恢复的进程和模式提供了又一实例。A post-Hangenberg Event microbial sediments occur overlying disconformablely on the bauxite-clay beds or fenestral limestone of the topmost Devonian in central and southern Hunan. They are distributed restrictedly in carbonate platform and were formed during the beginning of transgression in earliest Carboniferous,corresponding to the foraminifera Unilocular Zone and the coral Interval Zone between Devonian Cystophrentis and Carboniferous Uralinia Zones. This microbialite,7 to 30 m thick,consists mostly of oncolites and part clotted intraclasts with stripped and nodular appearance. It is similar to those occurred after the Latest Ordovician extinction event in western North America,and after the Permian-Triassic extinction in extensive area of the eastern Tethys and Panthalassa. Thus,the microbialite resurgence in association with low diversity ecosystems must be a common feature of post-extinction. The results would provide again a window into the patterns and processes of marine ecosystem restoration following the mass extinction.

关 键 词：微生物沉积 汉根卑尔格事件 泥盆-石炭系界线 核形石 凝块石 湖南 中国 

分 类 号：Q913[天文地球—古生物学与地层学]