ABSTRACT

The shapes of quartz grains contain a valuable record of their source and transport history. Grain shape can be measured with a Fourier series in closed form, which calculates the relative contribution, or amplitude, of 20 separate shape components (harmonics) to the total grain shape. Subsequent analysis of this grain shape data can determine the number of grain shape types (end members) present in suite of samples and their relative contribution in percentages to each sample; a knowledge of the nature and mixing proportions of end members, contributes to a better understanding of the source, transport history, depositional environment, and stratification of basin fill.

Two studies are used to illustrate this technique. The first is a study of the Pleistocene sediments of the Hatteras Basin, in which grain shape was used to monitor the input of sediments from two sources; the second is a study of the St. Peter Sandstone of Minnesota, in which grain shape was used to map eolian and aqueous beds in three massive, homogeneous sections of the formation.