Geochemistry of the siliceous black shales at Nagarjunasagar Damsite, India

Abstract

Analyses of samples from lenticular beds of siliceous black shales forming part of the Precambrian sequence unconformably overlying granitic rocks in the vicinity of the Nagarjunasagar dam show a low uranium and organic carbon content, ferric iron in excess of ferrous iron, and other features indicating that the depositional environment of the sediments was not characterized by the presence of sufficient organic matter or the sustained reducing conditions favorable to uranium concentration.