Reading segmented grain-size curves

Abstract

SummaryCumulative curves of grain-size against frequency often show segmented shapes which have been interpreted as the result of combination of normally distributed populations. The origin of the segments is explored by the examination of two classes of models, truncation and mixing. Similar curves may be generated by a variety of models. The segments rarely reflect precisely the original populations. Simulation of the tri-segmented curves commonly ascribed to combinations of suspension, saltation and traction populations shows that the characteristics of the contributing populations are not consistent with these three modes of transportation.