安徽灵璧叠层石岩石学和热化学特征研究

Study on Lithology and Thermochemical Characteristics of Stromatolites in Lingbi, Anhui Province

微生物碳酸岩是近年来地质学的研究热门,它是由于微生物的生长和生理活动的产物发生胶结作用和钙化作用形成的。各种微生物的不同作用,丰富的产出环境以及复杂的沉积环境让微生物碳酸盐成为了地质学家们的重要研究对象,特别是对微生物灰岩的研究,以及区分微生物成因的灰岩和普通灰岩的特征。本次实验主要通过XRD实验对叠层石的两个不同的部分,分别为暗色部分和浅色部分进行物相分析,判断两个部分的矿物成分和含量差异。通过热重实验绘制出两个不同部分的TG、DTG、DSC曲线,运用动力学计算出活化能,研究暗色部分和浅色部分之间的热化学性质差异性。根据图像分析两者的热分解变化情况和热力学特性。采用傅里叶变换红外(FT-IR)技术对有机官能团和矿物成分进行分析,叠层石浅色部分和暗色部分的矿物成分相同,均为方解石,但浅色部分的失重率比暗色部分高,而其活化能和热稳定性都低于暗色部分。Microbial carbonate rocks have been a hot topic in geological research in recent years. They are formed due to the cementation and calcification of products from microbial growth and physiological activities. The different functions of various microorganisms, rich production environments, and complex sedimentary environments have made microbial carbonates an important research object for geologists, especially in the study of microbial limestone, as well as distinguishing the characteristics of microbial derived limestone from ordinary limestone. This experiment mainly conducts phase analysis on two different parts of laminated stone, namely the dark and light parts, through XRD experiments to determine the differences in mineral composition and content between the two parts. Draw the TG, DTG, and DSC curves of two different parts through thermogravimetric experiments, calculate the activation energy using kinetics, and study the differences in thermochemical properties between the dark and light parts. Analyze the thermal decomposition changes and thermodynamic characteristics of both based on the images. Fourier transform infrared (FT-IR) technology is used to analyze organic functional groups and mineral components. The conclusion is that the mineral composition of the light and dark parts of the laminated stone is the same, both of which are calcite. However, the weight loss rate of the light part is higher than that of the dark part, and its activation energy and thermal stability are lower than those of the dark part.