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塔里木盆地西北缘的柯坪蓬莱坝剖面是研究寒武系微生物白云岩的良好剖面.此次研究提供了一个在微生物席和生物膜中由微生物沉淀白云石的实例.借助于高分辨率扫描电镜,在中上寒武统的叠层石白云岩的暗层中发现了直径为50~100 nm的球状小颗粒集合组成的球形白云石;和直径是50~170 nm,相互集中呈哑铃状或链状排列的球形白云石;以及硅化后的丝状体及成哑铃状或链状相连的显微结构.通过沉积学、岩石学和地球化学的研究,这些显微结构可能分别是白云石成核的最初阶段在微生物的作用下形成的纳米球粒;被胞外聚合物(EPS)或黏液等包裹而矿化的丝状物,及因硅化而保存良好的球形细菌(可能是蓝细菌).我们认为,作为一种独特的保护方式,硅化作用对于一些微生物席中的显微结构(包括有丝状和球状微生物及生物膜等)的保存,起到了重要的促进作用.同时胞外聚合物能够结合如硅、镁、钙等不同的元素,这些组分适宜球形细菌的矿化和有机底物上白云石的结晶.这些微生物显微组构的发现,可能为古代白云岩的微生物成因提供一些直观证据.
The Penglai dam profile at Keping in the northwestern Tarim basin is a good profile for studying the Cambrian microbial dolomites. This study provided an example of dolomite precipitation from microorganisms in microbial mats and biofilms by means of high-resolution scanning electron microscopy In the dark layer of the Middle-Upper Cambrian stratigraphic dolomite, spherical dolomites consisting of a collection of spherical particles with a diameter of 50-100 nm were found; and the diameters ranged from 50 nm to 170 nm, Spherical dolomites arranged in chains, and silicified filaments and dumbbell-like or chain-like microstructures that may be dolomite nuclei, respectively, through sedimentology, petrology and geochemistry The initial stage of the formation of nano-particles under the action of microorganisms; by extracellular polymers (EPS) or mucus wrapped and mineralized filament, and due to silicification of well-preserved spherical bacteria (possibly cyanobacteria). In our opinion, silicidation plays an important role in preserving the microstructure (including filamentous and globular microorganisms and biofilms) in some microbial mats as a unique protection method, while the extracellular The compounds are capable of binding different elements such as silicon, magnesium, calcium, etc. These components are suitable for the mineralization of spherical bacteria and the crystallization of dolomite on organic substrates.The discovery of the microstructure of these microorganisms may be caused by the ancient dolomite microorganisms Genesis provides some visual evidence.