论文部分内容阅读
对采自四川通江平溪坝二叠系-三叠系界线(PTB)剖面发育的微生物岩样品,选用2.5%盐酸、10%盐酸、10%氢氧化钠溶液、20%双氧水、10%醋酸以及0.1M乙二胺四乙酸钠(EDTA)进行处理,根据微生物岩表面处理结果的异同,和在扫描电镜(SEM)图像上的表现,确定最适合于微生物岩表面结构观察的化学处理方法是使用2.5%盐酸处理样品表面。用该法处理,并通过SEM观察发现,通常被当作白云岩的PTB微生物岩,实际上只是含有白云岩微晶的泥晶灰岩,微生物岩中含有与硫酸盐还原菌有关的大量的纳米级微球粒与形似草莓状黄铁矿的颗粒。通过实验结果对比分析了不同层位的微生物岩与白云岩的SEM微米级的特征和区别,以及建造微生物岩的微生物群落对其层位上下地层的影响。
Microbial rock samples collected from the Permian-Triassic Boundary (PTB) section of Pingxi Dam, Tongjiang, Sichuan Province were selected from 2.5% hydrochloric acid, 10% hydrochloric acid, 10% sodium hydroxide solution, 20% 0.1M ethylenediaminetetraacetic acid (EDTA). According to the similarities and differences between the results of the surface treatment of microbial rock and the performance on the SEM image, the chemical treatment method most suitable for the observation of the surface structure of the microbial rock is determined by using 2.5% hydrochloric acid treatment of the sample surface. Treated by this method and observed by SEM, it is found that the PTB microbial rocks, which are usually regarded as dolomites, are actually only micrite-bearing dolomite micrite, which contains a large amount of nano-sized sulfate-related bacteria Grade microspheres and particles resembling strawberry-shaped pyrite. Through the experimental results, the features and differences of SEM micrometer scale of microbial beds and dolomites in different layers and the influence of microbial communities on the formation of upper and lower strata are analyzed.