Structural characterization of the organic polymers comprising a lignite's matrix and megafossils

The geochemical and petrographic character of the matrix of the Oligocene, angiospermous Brandon lignite, Vermont, is examined and compared to samples of a common fossilized angiosperm wood and fruit endocarp contained within the lignite. The lignite matrix is composed primarily of humodetrinite and liptodetrinite while the megafossils are overwhelmingly humotelinitic (textinite and ulminite). Curie-point Py-MS, in-source Py-EI-MS, in-source Py CI-MS, and CPMAS 13C NMR reveal that the polymers comprising the matrix include a highly aliphatic polymer(s) and polymer(s) derived from the significantly modified remains of angiosperm lignin(s). Very few polysaccharides are preserved in the matrix. The polymer(s) in each megafossil contain(s) significant proportions of polysaccharides and lignins which are, however, significantly altered from their Recent equivalents. The results suggest that anatomical preservation and physical integrity of discrete megafossils within peats and lignites are directly related to the degree to which the original ligno-cellulosic framework is preserved. This implies that the humotelinitic macerals comprising the megafossils contain ligno-cellulose-derived polymers that are less modified than those comprising the humodetrinite within the matrix. The liptodetrinite within the matrix is probably comprised of highly aliphatic polymers derived from cutans and/or alginans. Upon further coalification the vitrinite within the vitrain bands derived from the megafossils and vitrinite within the clarain bands derived from the matrix would be distinct.