Grain size distribution - A probabilistic model for Usri River sediment in India

摘要

The present paper deals with the grain size distibution pattern of a modern river Usri, India. Sand samples were collected from the foresets of crossbeddings of specific size ranging in thickness from 23 to 40cm, developed on the point bars. Four point bars were chosen almost at a regular interval from the source to the mouth of the river Usri. The Usri is an ephemeral river of about 90 km in length and carries mainly the pebbly sands during monsoon discharge period. Grain size distribution pattern within point bar and between point bars were studied in the light of log-normal, log-hyperbolic and log-skew-Laplace distributions. Thus the best fit statistical model was developed to describe the longitudinal change of grain sizes vis-a-vis the sorting pattern with distance of transport.