微生物白云岩模式研究进展

Progress in the study of microbial dolomite model.

白云石(岩)问题一直是沉积学领域长期关注的研究主题之一。近年来,在研究含有白云石的现代自然环境和促进原生白云石的沉淀实验中,都加入了微生物因素,并取得了令世人关注的效果,这无疑为白云石(岩)的成因研究提供了新思路与新途径。在前人研究基础上,总结现有的观察资料和实验结果,将微生物促进白云石沉淀的机理模式归纳为厌氧模式和需氧模式2种,并分别介绍这两种模式中硫酸盐还原细菌、产甲烷菌和嗜盐好氧细菌促进白云石沉淀的机理;与微生物相关的矿物形态学特征中,球形和哑铃形白云石及白云石最初的成核阶段所形成的纳米球粒状结构具有一定代表意义,尤其是纳米球粒状结构可以作为生物矿物学上微生物白云石的标志性结构。通过这些特殊的形态特征来寻找微生物作用的证据,或可为古代相似成因白云石(岩)的成因研究提供一种标志。

Dolomite Problem has been a topic much attention being paid to in sedimentology for a long time.Recently,the recognition that microbes play an important role at low temperatures no matter in modern natural environments or in bacterial culture experiments provides a new perspective and develops a new field.Based on documented data,this article combining the microbial geochemistry conditions in bacterial culture experiments with the natural environmental conditions divides microbial dolomite mechanism into two modes： the anaerobic and the aerobic modes,and the authors detail the microbial dolomite mechanisms including sulfate-reducing bacteria,methanogenic Archaea and halophilic aerobic bacteria.The morphological characteristics of dolomite associated with microbe including spherical（spheroidal or ovoidal） morphology,dumbbell morphology and nanoglobule textures in initial nucleation stage are of representative significance.Especially the nanoglobule textures can be used as biomineralogical implications for dolomite formation at the nanometer scale.They were preserved in the geologic record,and used as microbial tracers through time and/or as a proxy for ancient microbial dolomite.