Lignin is a polymer comprised of a network of propylphenyl subunits linked by a series of phenolic ether bonds. It is known that the major precursor of lignin can survive, with only ring demethoxylation, early diagenesis during coalification and that subsequent transformation into aromatic macromolecule occurs during catagenesis. The application of lignin as a paleo- vegetation marker depends on the number of methoxyl groups present in the phenolic component of the lignin polymer. However, the stepwise degradation or demethoxylation of lignin in the diagenetic stage has not been extensively investigated. The research project will examine the lignin degradation products after short-term thermal alteration of wood and immature coals with and without mineral (clay) matrices. The results from this study should contribute significantly to the understanding of the chemical changes undergone by the precursors of coal during peatification and early coalification. The data should provide important information on the use of lignin as a paleo- vegetation biomarker and paleoclimatic indicator in sedimentary rocks, peats and coals. Further, the artificial pyrolysis trends could be applicable to real geological samples such as coals in correlating the diagenetic changes of lignin phenols.
