Evidence of Pyrolysis of Resinite in Coal through Thermal Maturation Vis-à-vis Hydrocarbon Generation: an Example from the Oligocene Coals of Upper Assam

Petrographic examination of Oligocene coals of Upper Assam has shown some morphological changes in the Maceral-Resinite, which is suggestive of their pyrolysis due to thermal maturation. It has been observed that the resinites of these coals resemble in optical properties, including the microstructures, to the artificially pyrolyscd resinite (up to 330°c/72hr) of Middle Jurassic coals of northeast Greenland. Since the Upper Assam crudes are high wax oil, this observation seems to be one of the potential evidences in support of the growing perception that coals of this basin (of the Barail Group) have acted as source for the oil in the same geological horizon.