Plant fossil orientation in Early Permian Barakar Formation of eastern-central India Gondwana basins

Abstract

The long axis orientation of plant fossils including Glossopteris, Gangamopteris and Vertebraria preserved in carbonaceous shale/siltstone lithofacies of Early Permian Barakar Formation from nine coalfields of eastern-central India has been analysed for preferred elongation. The resultant average suggests northeast-southwest trends in Raniganj, Jharia, East Bokaro, North Karanpura, Talchir, Korba and Singrauli coalfields, and east-west in the Saharjuri and Jainti coalfields. The preferred linear trends in the long axis of plant fossils indicate their genetic relationship with the attending flow. It is argued that the plant debris which decomposed to form coal in Early Permian Barakar Formation of eastern-central Gondwana basins was largely of transported or drifted nature. The linear trends of plant fossils are closely comparable to ripple asymmetry, and exhibit oblique or near transverse relationship with the dominant current system. It would imply an angular relation in the deposition of fine clastic and coarse grade lithofacies, respectively. The fine clastic lithofacies of carbonaceous shale/siltstone containing oriented plant fossils is attributed to deposition in overbank subenvironment of the fluvial system.