Petrography and Depositional Environments of the Permian Coal Deposits of Deoghar Basin, Bihar

In the present paper an attempt has been made to carry out the petrographic characterization of coals from the Deoghar basin and to reconstruct the palaeoenvironmental conditions of coal formation using macerals and microhthotypes as tools For this purpose a large number of pillar coal samples from the Karharban and Barakar seams were collected and were subjected to detailed petrographic examination The results indicate that the Karharban coals are rich in inerlimte while the Barakar coals are comparatively rich in vitnmte The rank of Deoghar coals (as per ASTM system), on the basis of the mean of random vitnnite reflectance, has been found to range between Sub-Bituminous 'B' and High Volatile 'C Bituminous The quantitative relationships of macerals, microhthotypes and mineral matter show that these coals have originated from the transitional plant communities in open to forest moor and under limno-telmatic to hmnic conditions Moreover, the Karharban coals have evolved under oxic moor conditions with sudden high flooding while the Barakar coals have evolved under comparatively wet moor conditions with intermittent moderate to high flooding Low values of TPI and GI indicate periodic dryness in the basin This contention is supported by the dominance of inertodetnnite particularly in the coals of Karharban Formation.