Microbialite of anoxic condition from Permian-Triassic transition in Guizhou,China
会议名称：《中国科学院地质与地球物理研究所2007学术年会》
会议日期：2008年
学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学]
基 金：Supported by the National Natural Science Foundation of China(Grant No. 40472015) the State Key Laboratory of Modern Paleontology and Stratigraphy (Grant No.053102) and as well as the Key Laboratory for Minerals and Resources,the Chinese Academy of Sciences
关 键 词：Microbialites reefs Permian-Triassic boundary mass extinction end-Permian
摘 要：Spherical microfossils are present in the Hindeodus parvus zone of the Lower Triassic in Ziyun, Guizhou *** generally range from 0.15 to 0.30 mm across,with micritic wall and filled by micro-sparry calcites,and are evenly scattered in micritic *** abundance makes the rock assigned to *** accompanied organisms include ostracods and algal mat,but no gastropods or *** of small(7μm) pyrite framboids indicates that this bed formed in anoxic *** some sections,this bed is overlain and underlain by tidal-flat micritic limestone with microgastropods and small *** only in deposits on reef top indicates that the microbial organism was benthic,and needed sunlight in *** size of the microbial fossil exceeds that of any bacteria or ***,it does not belong to these two *** may belong to lower green algae,and is assigned to a new species in a new genus,Ziyunosphaeridium sinensis *** ***. Up to now,the rocks described as microbialites from the Permian-Triassic transition include six types: (1) porous micritic limestone such as that descried from Japan by Sano and Nakashima(1997),(2) limestone with rich globular microfossils such as that described from the Nanpanjiang Basin in China by Lehrmann(1999),(3) dendroidal limestone such as that described from the vicinity of Chongqing by Kershaw et al.(1999),(4) spherical microbial limestone adapted to anoxic environments described from Ziyun,Guizhou reported in this paper,(5) limestone with cyanobacterial fossils such as that described by Wang et al.(2005),and(6) *** these microbialites are not reefs in the proper sense, and the argument that Permian reef ecosystems extended into the Mesozoic is incorrect.