Determination of Sedimentary Environment through Grain Size Analysis of the Tyrsad and Weiloi Area, Meghalaya, India

Abstract

Grain size characterization plays a vital role in understanding the environment of deposition. The study has been carried out along Tyrsad and Weiloi area of conglomerate outcrop, Meghalaya, India. The grain size statistical analysis has been carried out by using the Geometric (modified) Folk and Ward (1957) graphical measure, where the textural analyses of the grain size parameters reflect the history of its sedimentation. The result revealed that the maximum grain size of the conglomerate ranges between coarse-grained sand to granule grain-size, suggestive of the sediments being deposited under high-energy conditions.  The analysed sediments show a standard deviation of 0.3 to 0.32. The sediment analysed indicates a very well sorted grain size and skewed towards the very coarse grain sizes in an extremely leptokurtic condition revealed that the sediment samples have achieved its sorting in high-energy environment. Interpretation of the frequency curve suggests that bulk of the sediments were transported in the form of traction and saltation. The sharp break in frequency curve indicates fluctuating energy during deposition. The study aims to address the paleo environmental depositional of the conglomerate as these deposits hold a significant geo-heritage importance.