On the Origin of Fusain in the Tertiary Coals of Meghalaya

The fusain fragments separated from the Tertiary coals of Meghalaya were studied under a high performance Scanning Electron Microscope. The transverse view (across the bedding plane) of these charcoalified plant tissues shows the preservation of micro anatomical details together with complete absence of middle lamella leading to cell-walls homogenization. The homogenization of cell-walls suggests that fusain of these coals has originated due to the pyrolysis of woody tissues. Pyrolysis took place during the intermittent dry seasons by the generation of forest fires in the basin. Disappearance of middle lamella zone from the cell-wall points that charcoalification temperature was 400°C. Further, charring of wood at a high temperature is indicative of the high oxygen level during the development of coal facies.