Petrology and Palynostratigraphy of some Wardha Valley Coals, Maharashtra, India

Abstract

The present paper deals with the petrographic and palynological studies of Wardha Valley coals of Maharashtra, India. The coals are generally dull, hard, granular and indistinctly banded. Durain forms the dominant constituent in the coal seams. It occurs as thick bands of hard, compact and granular mass, having dull lustre. Clarain is the next dominant constituent of these coals which is more common in the south-eastern part of the coalfield. Fusain is present in the form of thin patches and lenses. Vitrain occurs as thin bands except at places where it has attained considerable thickness of local importance. Microscopic study of durain components indicates inertinite, vitrinite and exinite as main macerals. Microspores and megaspores are found mainly in exinite constituents. Microscopic analysis of coals also indicates that durite, fusite and vitrite are the important microlithotypes. The inorganic mineral matter is mostly composed of clay minerals; silica and pyrite.

Sporological study of Wardha Valley coals reveals the presence of trilete, monolete, monosaccate and disaccate forms. Brevitrileles, Horriditriletes, Lophotriletes, Microbaculispora, Microfoveolatispora, Parasaccites and Scheuringipollenites are well represented genera in these coals suggesting the Lower Barakar affiliation.

The petro-palynological study of Wardha Valley coals indicates that the coals are derived from Permian coal swamps of Lower Barakar entities (based on spores and pollen analysis) which metamorphosed into a dull coal type (durain type-characteristic of Barakar Stage) showing variable coalification towards the south eastern part of the coalfield due to probable changes in physio- chemical conditions. The petrological composition shows a high proportion of "inerts" and sedimentary matter in the coals which may cause problems in coal preparation for utilization. However, the coal quality may be improved by selective sampling, screening and cleaning processes. The petrographic analysis of coals from different collieries reveals better type of coal in the southern part of the coalfield and hence, it is suggested that this area is more promising for working, and for future exploration.