The Use of Factor Analysis in Determining Depositional Environments from Grain-Size Distributions

Abstract

ABSTRACT A multivariate statistical technique, factor analysis, can be used to advantage in determining the depositional environment of sediments from, their grain-size distribution. This factor-analysis technique has been applied to sixty-nine recent sediment samples collected from Barataria Bay, Louisiana. To describe adequately the grain-size variations in these samples, three factors were determined. These are postulated as representing three basic kinds of energy responsible for the deposition of sediments: wind-wave energy, current energy and gravitational energy. This implies that, in Barataria Bay, grain-size distribution is determined by the relative amounts of these three energy types that are active at a depositional site. Further, the relative amounts of the energies are given by t e factor loadings. The factor-analytical approach offers certain advantages over previously described techniques: 1. It makes use of the entire spectrum of the grain-size distribution. 2. It does not require arbitrary statistical descriptions of the grain-size distribution; hence the analytical method can be more objective. 3. It demands no a priori knowledge of the environmental and geographic location of the sediment samples for classifying them into environmentally distinct facies. This should make the technique particularly applicable to problems dealing with ancient sediments.