Petrography and geochemical study of the barail sandstones in and around Ukhrul area Ukhrul district Manipur India

Abstract

The present research work emphasizes the sedimentation and lithification process of the Barail sandstones occurring in and around Ukhrul area, Ukhrul district, Manipur, India. The research problem is addressed through systematic studies which are embodied in eight chapters and briefly summarized below. The first chapter is on the introduction to the problem, objective of the study, scope of the study and previous literature. Geologically the area represents the central part of the IMR (Indo-Myanmar Range) lies in the inner Palaeogene fold belt of Manipur Nagaland - Upper Assam and Arunachal Pradesh. A large spread of Disang Group with isolated covers of Barail Group characterizes the geological setting of the area. Mainly two lithostratigraphic units are found in the study area, viz, the Disang and the Barail groups. In the folded and faulted terrain, the Disang rocks occupies the anticlines and the younger Barail sediments occur in the core of major synclines. Disangs constitute the oldest rocks covering a large part of the study area. The age of Disangs ranges from Upper Cretaceous to Eocene. The Disangs are overlain conformably by the Barails which are of Oligocene age. They are usually alternations of shales and sandstones. The base of the Disangs is nowhere exposed as it is invariably truncated by the Disang Thrust. In general, the frequency and thickness of sandstones and siltstones seem to increase toward the upper part of the Disang sequence which gradually becomes arenaceous and thickness of sandstones considerably increase that marks the contact between the Disanges and the Barails. The arenaceous rocks of the Barail Group have quite distinct physical identity which differentiates them from the rocks the Disangs. The present study aims to investigate the characteristics of the Barail Sandstones in term of their petrography, mineralogy and geochemical properties. The objectives of the study are to prepare a detail geological map of the study area, to systematic survey of the Barail sandstones, to...