Acheulian artefacts and tephra from Upland Western Maharashtra (Deccan Volcanic Province), Peninsular India

Abstract

Abstract The two Early Acheulian sites of Bori and Morgaon in the Deccan Volcanic Province in Upland Maharashtra, India bear some association with an acidic tephra deposit in a fluvial context. Acheulian artefacts in association with tephra were first reported in India from the Bori site and numerous efforts to date this tephra have since been undertaken. These efforts employed various dating methods and produced a total of 10 absolute dates ranging from the Early Pleistocene with a maximum age of 1.4 Ma to the Late Pleistocene with a minimum age of 23.4 ± 2.4 ka. However, field observations and a typo-technological analysis strongly suggests that these Early Acheulian artefacts occur in a semi-primary context, and thus contest the Late Pleistocene age of the tephra and redeposition of the artefacts as argued by some scholars. At Morgaon, the Acheulian artefacts have been recovered from basal fluvial sediments that contain clasts of laterite. These sediments are capped by two low-energy clay facies that are separated by high-energy gravel lenses. The tephra at Morgaon has been reported from the upper clay facies and has produced absolute dates ranging from the Matuyama period (>0.78 Ma) to the Late Pleistocene (41 ka). After more than two decades of investigation at these sites, the number of absolute dates procured through methods such as electron spin resonance (ESR), 39 Ar– 40 Ar, U–Th and palaeomagnetism, although encouraging, are inconclusive. This paper is therefore an attempt to gauge the nature of the palaeolandscapes that most probably existed during the Early Quaternary. This will be achieved by studying local geomorphological variability between the two sites, along with a preliminary analysis of lithic morphology.