Discrimination of depositional environments using settling tube data

Abstract

The settling-velocity distributions of more than 500 modern and near-modem river, dune, beach, tidal-flat, and turbidite sediment samples were analyzed using a photo-extinction settling tube. Discriminant function analysis was applied in order to investigate the possibility of extracting environmental information from settling velocity distributions using 65 variables that describe distribution curves. The results showed that 1) good discriminations were obtained between reference of river, beach, and dune sediments; 2) reliable answers were obtained through identification tests of unknown sets using reference sets: 3) the Triassic (?) and Jurassic Navajo Sandstone samples were mostly grouped as eolian (dune) when compared with the analyzed of samples; and 4) the variables useful for environmental discrimination were chiefly related to the tails of distributions. Some variables commonly used for environmental analysis (e.g., mean value and sorting) were found to be more influenced by provenance factors than by environmental factors.