Fossil charcoal as Palaeofire indicators: Taphonomy and morphology of charcoal remains in sub-surface Gondwana sediments of South Karanpura coalfield

Abstract

Macroscopic charcoal is recovered from the sub-surface sediments from Bore core SKB-1 which intersected Barren Measure Formation and Raniganj Formation of South Karanpura coalfield. These charcoal particles are widely accepted to be of palaeowildfire products and this study contributes to the Middle and Late Permian wildfire data of Indian peninsula. In the present investigation the charcoal particles are studied using reflected light, transmitted light and Scanning Electron microscopy to document their anatomical structure, morphology and temperature of formation. The inertinite reflectance data reveal that these charcoals were formed at a temperature of 600° C which is evident by the homogenized cell walls as homogenization takes place at temperatures above 500° C. Petrographic analysis reveals high inertinite content and the calculated Gelification Index and Tissue preservation Index suggest that the sediments from which the charcoal particles were retrieved were deposited in a dry forest swamp which was conducive for the forest fire to propagate as the forest litter provided the fuel load. The morphological characters of charcoal were utilized in delineating its taphonomy and it indicates that they are hypautochthonous in nature.