Petrographic and Fluorescence Spectral Properties of Liptinite and Vitrinite Coal Macerals

摘要

The purpose of this study is to gain a better understanding of the properties of various coal macerals. Because it is both expensive and very difficult to separate the various macerals from coal, the macerals were studied in situ by quantitative fluorescence microscopy. This method has only recently been applied to the study of coal and has already lead to the discovery of new macerals, and a better understanding of coal rank and the coalification process. The results of this study showed that many fluorescent macerals are undercounted in normal white-light analysis and that additional structures and textures are often visible in fluorescence analysis. Fluorescence spectral analysis of various samples of the Herrin (No. 6) and Springfield-Harrisburg (No. 5) seam from Illinois and the Hartshorne seam from Oklahoma can quantitatively distinguish various maceral types and two or more varieties of each type. For example, in all of the seams examined, two varieties of the maceral, fluorinite, were characterized. To avoid nomenclature problems caused by the abundance of new maceral varieties, the concept of spectral type was developed. In samples of different rank from each of the three seams the fluorescence properties of fluorinite, sporinite, and cutinite show a systematic change with an increase in coal rank. In addition, secondary macerals were also identified - semi-fusinite and vitrinite. These macerals were specific to the host maceral and also showed a change in spectral properties with rank.