For the glacial till and glaciolacustrine samples it was necessary to estimate the values of the 84 th and 95 th percentiles by extrapolating a straight line off the graph. 5.0 0.031 Glaciolacustrine 8.8 0.0022 9.0 0.002 2.0 0.25 Q6. The dune sample is the best sorted. The river bar deposit is moderately sorted. The dune sample is well sorted because of the environment in which the sample was transported and deposited.
Beach sand is subjected to reworking by waves.
Materials are moved up and down the beach face repeatedly. The grain size of the beach materials becomes very uniform over a period of many years. When the sand dries out, some can be mobilized by wind and transported off the beach. These wind blown sands are deposited in dunes. The glaciolacustrine sample consists almost entirely of silt and clay but there is a large range of materials, from very fine sand to fine clay.