Numerical classification of coal-bearing cycles of early Permian Barakar coal measures of eastern-central India Gondwana basins using Q-mode cluster analysis : Tewari R.C., Journal - Geological Society of India, 1997, 50/5 (593–599)

Abstract

Q-mode cluster analysis is applied to classify the fining upward cycles of Early Permian Barakar coal measures from 14 localities of eastern - central India Gondwana basins. Two distinct clusters are recognised on the basis of overall similarity of upward transition probability values of embedded Markov chain statistics. Cluster A comprise 9 localities representing fining upward asymmetrical cycles of very coarse to coarse sandstone → interbedded fine sandstone-shale→ shale → coal → coarse sandstone, whereas Cluster B include 5 localities represented by symmetrical cycles i.e. very coarse to coarse sandstone → interbedded fine sandstone-shale → shale →coal →shale. The development of asymmetrical cycles together with abundance of very coarse to coarse sandstone is attributed to rapid lateral migration of braided channels, whereas the deposition of symmetrical cycles with subequal amount of coarse to medium sandstone and fine clastics including coal correspond to slow and gradual overstepping of meandering stream channels and associated subenvironments across the alluvial plain.