Genesis of micrinite in some Australian coals

Seven Australian coals have been examined petrographically and two types of micrinite, disseminated micrinite and cavity-filling micrinite, are described. The disseminated micrinite appears to be very fine fragments of fusinite, semifusinite and other low reflectance inertinite. Cavity-filling micrinite occurs only in inertinite-rich coal seams and was formed under aerobic conditions. It is considered that porigelinite and other granular material in peat are the major progenitors of the cavity-filling micrinite. Such progenitors would have entered cell cavities and other voids, possibly as a water slurry, before or after they had been partially oxidized.