A study on Microvertebrate Fossils from the Eocene Kapurdi Formation, Barmer District of Rajasthan: Implications for Age and Palaeoenvironment

Riya Bidaye

St. Xavier's College, 5, Mahapalika Marg, Mumbai, 400001

Prof. Guntupalli V. R. Prasad

University of Delhi, 34, Chhatra Marg, Faculty of Science, Banarsi Das Estate, Timarpur, Delhi, 110007

Abstract

The aim of this project is to extract and study microvertebrate fossil remains from the Kapurdi Formation of Barmer, Rajasthan. The project includes processing of samples, extraction of fossils from screen-washed residue, and identification of fossil taxa. Furthermore, these fossils have been used to determine the relative age of the fossil-yielding rock strata and their depositional environment.

The fossiliferous samples consisting of green carbonaceous shales occur in association with lignite seams of Kapurdi Lignite Mine, Barmer District, Rajasthan. These samples were disaggregated by soaking in kerosene and water, and then washing using progressively smaller ASTM sieves. They were simultaneously separated into fractions based on grain size. The concentrate thus obtained was dried and sorted under a binocular microscope. Sorting yielded microvertebrate fossils belonging to at least 17 genera encompassing about 23 species. Among these, many have been reported previously from other locations in India, including the Subathu Formation of Himachal Pradesh, and the Khuiala Formation of Rajasthan. The genera Archaeomanta and Heteroptychodus, however, appear to have been reported here for the first time in India.

The age and palaeoenvironment of the locality are interpreted using the fossil assemblage. The age is found to be Middle Eocene and the environment, shallow marine and tropical. The conclusions regarding palaeoenvironment are supported by the grain size and mineralogy of the sample.

Keywords: Microvertebrate extraction, relative age estimation, palaeoecology, systematic palaeontology, Elasmobranchii