Particle-size analyses of Widgelli Parna in South-east Australia

Abstract

Difficulties in using granulometry to characterize the non-clay fraction of the presumed aeolian sediments known as parna are considered by reference to the results of repeated analyses of samples. Incomplete dispersion of clap accounted for different results with two samples, one being from material identified as subplastic. Bimodal size frequency distributions were detected for several samples, a condition which should invalidate modal diameter as the measure of average grain size. Mean diameter is regarded as an appropriate measure for the samples. The more accurate results obtained for the samples do not upset the earlier conclusions regarding distribution of Widgelli parna, but they suggest an important distinction between the western and eastern samples of the material. Suggestions are made concerning determination of particle size for parna samples.