Stream-scanning laser system, electric sensing counter and settling grain size analysis: a comparison using reference materials and marine sediments.

Surface and deep-sea core sediments and two sets of standards were measured by three different techniques - Galai Cis I laser system, Coulter Counter TAII, and Micromeritics SediGraph 5000D - in order to compare the Galai results with the other two. The differences between the three types of measuring device turned out to be greater in sediments than in standards, and were attributed to the physical properties, shape, density and composition of the particles (complexity of the matrix). Comparison between moment statistics showed that the Galai determines coarser grain sizes than the Coulter and finer than the SediGraph, particularly as regards analysis of surface sediments. The relationships between Galai and SediGraph were estimated using analysis of variation/residuals within individual intervals. The analysis showed a higher variability of residuals for the coarser fractions (8-16 µm and 16-32 µm) with respect to the finer (2-4 µm and 4-8 µm) fractions. The <2 µm SediGraph fraction, with a cut-off at 0.49 µm, showed good correspondence with the <2.5 µm Galai analysis.