Sorting (sediment)

Sorting describes the distribution of grain size of sediments, either in unconsolidated deposits or in sedimentary rocks.

The degree of sorting is determined by the range of grain sizes in a sediment deposit and is the result of various transport processes (rivers, debris flow, wind, glaciers, etc.).

In the field, sedimentologists use graphical charts to accurately describe the sorting of a sediment using one of these terms.

Normal tangential sorting results in a gradient of sediment sizes deposited from largest to finest as they travel downstream.

[2] When sediments are deposited from smallest to largest as they travel downstream, this is referred to as reverse sorting.

Sediment consisting of well sorted grains (left) compared with poorly sorted grains (right).
Distribution of grain sizes based on water depth and distance from river mouth.