Measurement of Fine Silt and Clay Size Distributions

THREE different commercial particle-size analyzers were compared with the conventional pipet technique to measure the size distributions of 15 samples of very fine sediments. These samples were obtained from the deposited sediments in several oxbow lakes in the alluvial plain in west central Mississippi. Approximately 90% of the material in these samples were less than 10/im in size. The basic features, principles and underlying assumptions for each instrument are outlined and compared for all analyzers and techniques used. While the results from the four methods showed drastic differences, reconciliation of these data was achieved by use of simple mathematical descriptions of the particle size distributions and of the measurement processes involved with each instrument.