Geochronology of Palaeolithic cultures in the Hiran Valley, Saurashtra, India

Abstract

The U and Th concentrations of 16 miliolite samples from the Hiran Valley in Saurashtra ranged from 0.3 to 2.14ppm and 0.12 to 0.82ppm respectively. The ²³⁴U/²³⁸U activity ratio ranged from 1.09 to 1.16, with a mean of 1.12±0.02. It agrees well with the seawater value of 1.14±0.02 within the quoted errors. Nine of the samples were datable by the ²³⁰Th/²³⁴U method and the ages ranged from 56.8 to 190 Kyr. The problem of chronology of Palaeolithic artifacts is interlinked with the miliolite and other coastal formations. The present investigations permit the development of a chronological framework for the Palaeolithic cultures in the Hiran Valley in particular, and generally in Saurashtra Peninsula. On the basis of radiometric dates and relative chronology, the Lower Palaeolithic cultures fall in a time-bracket of 190-69 Kyr bp. The Middle Palaeolithic industry is much older than 56.8 Kyr bp. The dates obtained for the Lower Palaeolithic cultures are perhaps the oldest reported to date.