Petrochemistry and Depositional Environment of Permian Coals of Basundhara Block, Ib-Valley Coalfield, Orissa, India.

摘要

This paper deals with the characteristics of coals of Basundhara block of Ib-valley. The aim of this study is toreconstruct the paleo-environment condition of coal formation. A large number of pillar coal samples from Basundharablock were collected and subjected to detailed petrographic and geochemical studies. The results show that the Basundharablock (Rampur seam) coals are rich in inertinite group macerals. The rank of Basundhara block coals as per ASTMsystem and according to the mean of random vitrinite reflectance has been found to range between sub-bituminous ‘A’and high volatile bituminous ‘B’. The proximate analyses exhibit that coals belong to semi-coking to weakly cokingrange. The ultimate composition shows hydrogen ranges between 4.87 and 6.20%, carbon from 78.7 to 86.3% andoxygen between 7.26 and 13.78%. The nitrogen ranges from 0.71 to 0.76% and sulphur is between 0.53 and 0.96%. Thequantitative study of macerals, microlithotypes and mineral matter indicate that these coals originated from the plantcommunities of highly fluctuating oxic and anoxic moor to oxic (dry) moor with sudden high flooding conditions. Lowvalue of Tissue Preservation Index (TPI) and high value of Gelification Index (GI) indicate peat formation in drycondition.