MICROFAUNA FROM THE EARLY PALAEOGENE LIGNITIC DEPOSITS OF BHAVNAGAR LIGNITE MINE, GUJARAT, INDIA

Abstract

The Cambay and Kutch basins of Gujarat, western India exposesome of the best developed Tertiary sequences in India. The succession includes several lignite deposits ofprimarilyEocene age, which are being commercially exploited at present in the form of open cast lignite mines in the state. In Cambay basin, Vastan lignite mine shows abundant microfaunal forms, which is been dated as of Eocene age. Recently, an open cast mine has come up in Bhavnagar district near Surkha village of Khadsaliya clays formation. Previously in this area, an attempt on Palynostratigraphy is made resulting in a good frequency of pollen and spore taxa. The present dissertation is the first attempt aimed at the recovery, taxonomic identification and assessment of age and palaeoecology based on the microfossils from Bhavnagar lignite mine. The faunal assemblage recovered from the Bhavnagar lignite mine includes fish otoliths, fish vertebra, bivalves, gastropods and ostracods. Some of the microfauna from Bhavnagar lignite mine shows affinities towards the respective microfaunal assemblages of the Vastan lignite mine, which is stated to be of early Eocene age. Fish otoliths includes "genus Ambassidarum", "genus Apogonidarum", "genus Percoideorum" and Gobiidarumvastani, out of whichGobiidarumvastaniis an age diagnostic, of early Eocenefound in Vastan Lignite mine. Presence of both fresh water (Lepisosteus, Osteoglossidae) and shallow marine water (Enchodus, Egertonia and Stephanodus) fauna of fish vertebra and fresh water (Cypridopsis) ostracods suggests that Bhavnagar lignite mine have an assemblage of admixed fauna.