陕西宁强早志留世灰泥丘中微生物及其造岩意义  

MICROBIAL FOSSILS IN LOWER SILURIAN MICRITE MOUND, NINGQIANG, SOUTHERN SHAANXI

作　　者：张廷山[1] 边立曾[1] 俞剑华[1] 兰光志[2] 孙蓬育 

机构地区：[1]南京大学地球科学系,南京210093 [2]西南石油学院勘探系,四川南充637011

出　　处：《古生物学报》2000年第2期263-266,共4页Acta Palaeontologica Sinica

基　　金：油气藏地质与开发工程"国家重点实验室基金项目成果之一! (编号 :950 7971 2 0 0 5)

摘　　要：通过扫描电镜分析 ,在陕西宁强早志留世深缓坡微晶灰泥丘中发现 3种微生物化石 ,分别为 :( 1 )表面光滑卵球体 ,其大小为 5μm× 3μm ,壳体表面光滑 ,长轴端具有圆形凹坑或凸起 ,可能为芽体及芽痕 ;此类化石能与真菌类菌孢对比 ;( 2 )表面粗糙的椭球体 ,其大小为 60 μm× 50 μm ,壳体表面粗糙 ,具蠕虫状断续条纹 ,并有方解石胶结物生长 ;( 3)网格状结构 ,由钙化的胶质席状物及枝状物组成 ,网呈枝状分叉 ,盖覆于灰泥之上并参加造岩。经能谱分析 ,所有微生物化石均由碳酸钙组成 。The Early Silurian storm influenced siliciclastic and carbonate ramp environment was recognized from the north margin of Sichuan Basin. According to the SEM studies, three kinds of microbial fossils are found in the deep ramp micrite mound of Ningqiang, Shaanxi and reported herein: (1) Smooth ball like body fossil with egg shape, 5μm×3μm in size, has smooth shell with bud and bud scar or birth scar developed, and can compare with yeast through the comparative studies; (2) rough ellipsoid fossil, 60μm×50μm in size, has rough surface and calcite cementation developed on it and might serve as catalysts for creation of the cement; (3) foamed network like fossil is formed by foamed network biofilm material covered the micrite, some small branches stretched out from the main part of the fossil. The branches are composed of foamed network material and they show biocement characteristics. The shape of the fossil suggests that it be one kind of algae. From the data of EDAX analysis, all microbial fossils are composed of calcite and they might play a role in the formation of calcium carbonate in the micrite mounds.

关 键 词：微生物化石 灰泥丘 造岩作用 早志留世 

分 类 号：Q91[天文地球—古生物学与地层学]