Age of Saurashtra miliolites by U-Th decay series methods: possible implications to their origin

Abstract

The miliolite deposits of Saurashtra have been dated by ²³⁴U, ²³⁰Th, ²³¹Pa and ¹⁴C methods. Concordant ages of ~10⁵ years using the U decay series isotopes are obtained which agree with the ages of the coral reefs of Okha-Dwaraka coast suggesting a contemporaneous origin for both. The lower ¹⁴C ages (≤40,000 years) may be due to a recent influx of seawater or ground water. Quartz and clay minerals together constitute only ≤ 10% by weight, as such the aeolian characteristics of quartz grains may not be relevant to the origin of the miliolites.