Medullosalean fusain trunk from the roof rocks of a coal seam: Insight from FTIR and NMR (Pennsylvanian Sydney Coalfield, Canada)

Results indicate that the fusinite is characterized by long and narrow xylem fibers, without fungal signals, and cell structures infilled with pyrite and carbonate. FTIR spectra of the fusinite and secretinite are similar particularly in respect to high absorbance of aromatic and low absorbance of aliphatic compounds, and absorbance of Si-O functionalities relating to kaolinite. 13C NMR experiments with direct carbon excitation quantify the aromatic to aliphatic ratio as being 20 ± 3:1. As part of the taphonomic history, the evidence favors a hot, > 400 °C, directional surface-fueled flame palaeofire of local extent that charred trunks of growing arborescent seed ferns on only one side, and that these trunks were transported to comprise part of the roof rocks of the Hub Seam.