柴达木盆地新近纪叠层石中微生物化石组合的发现与钙化方式研究  

Discovery of Microorganism Fossil and Study on Microorganism Induced Calcification in Miocene Stromatolites,Qaidam Basin,China

作　　者：温志峰[1,2] 刘显太[1] 钟建华[1] 李勇[3] 王海侨[4] 

机构地区：[1]中国石化胜利油田地质科学研究院,山东东营257000 [2]中国石油大学(华东)地球资源与信息学院,山东东营257061 [3]中海石油(中国)有限公司北京研究中心,北京100027 [4]中国科学院地质与地球物理研究所,北京100029

出　　处：《地质学报》2010年第2期263-271,共9页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号20053003);教育部博士点基金(编号20030425008;20060425509)资助成果

摘　　要：在柴达木盆地西部新近纪叠层石纹层中第一次明确发现了保存完好的微生物化石,其中包括微米级别的微生物球状构造,亚微米级的生物颗粒构造以及矿化的席状和片状有机组织。结合目前国内外的研究成果可以确定暗层中微米级球状构造为类似于Coccoid的硫还原微生物,亚微米的球状颗粒一方面是叠层石微生物席胞外聚合物质(EPS)的重要组成部分,另一方面也是极端条件下微生物体脱水收缩以后的产物,而片状和席状构造则是矿化的EPS以及微生物膜。通过对亮层和暗层中生物构造、石英、石盐以及方解石矿物的分析,可以确定叠层石的形成过程分为暗层有机主动矿化和亮层无机原地沉淀,其中的暗层矿化则分为上层封闭酸性环境中的光合作用,以及下层相对封闭环境中的硫还原和EPS的降解钙化作用,上部的亮层则主要为原地沉淀无机成因并在成岩过程中受到了暗层中有机质的影响。It is hitherto first found home and abroad that the mineralized micron-sized biological spherical structure, sub micron-sized biological granular structure and biological induced sheet organic structure are well preserved in the laminations of Miocene stromatlite in the western Qaidam basin. Combined with the recent study home and abroad, the micron-sized spherical structure is a kind of sulfate reducing microorganism similar with the Coccoid, and the sub-micron-sized granular structure is an important part of the EPS and may be the product of shrinking microorganisms under extreme conditions, and the sheet structure is the mineralized EPS and biofilm. Based on the analysis of the biological structure above and the crystals, such as quartz, salt and calcite, it can be confirmed that the formation of stromatolite in the study area may undergo two processes, the organic active mineralization for the dark lamination and the inorganic in-situ precipitation for the light lamination, among which, the mineralization of the dark lamination may be furthermore divided into two phases： the photosynthesis within the upper enclosed acid microenvironment and the sulfate reduction and EPS mineralization by means of degradation in the lower semienclosed micro environment, in contrast, the light lamination is mainly the product of in-situ inorganic precipitation with some influence from the organic matter preserved in the dark lamination during the lithofication.

关 键 词：中新世 叠层石 微生物化石 有机成因 钙化模式 

分 类 号：Q913.2[天文地球—古生物学与地层学]