CAJ | 학술논문

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.
재시체목분지서부신근기첩층석문층중제일차명학발현료보존완호적미생물화석,기중포괄미미급별적미생물구상구조,아미미급적생물과립구조이급광화적석상화편상유궤조직.결합목전국내외적연구성과가이학정암층중미미급구상구조위유사우Coccoid적류환원미생물,아미미적구상과립일방면시첩층석미생물석포외취합물질(EPS)적중요조성부분,령일방면야시겁단조건하미생물체탈수수축이후적산물,이편상화석상구조칙시광화적EPS이급미생물막.통과대량층화암층중생물구조、석영、석염이급방해석광물적분석,가이학정첩층석적형성과정분위암층유궤주동광화화량층무궤원지침정,기중적암층광화칙분위상층봉폐산성배경중적광합작용,이급하층상대봉폐배경중적류환원화EPS적강해개화작용,상부적량층칙주요위원지침정무궤성인병재성암과정중수도료암층중유궤질적영향.
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 micro-environment and the sulfate reduction and EPS mineralization by means of degradation in the lower semi-enclosed 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.