The grain-size, also known as particle size, is a basic parameter that refers to the size distribution of the sedimentary individual grains. The method applies to unconsolidated sediments and relies on analyzing the light scattering from the fringe at the contact with a small sized particle, following Fraunhofer or Mie theories. The sedimentary detritic material can range from very coarse particles, such as boulders, cobbles and pebbles to colloidal particles such as clay minerals.
We follow a strict methodology of sample preparation which includes chemical treatment for removing organic matter in sediments and dispersion of flocculated colloidal particles. The laser analyzer is capable to measure in a range of 2 μm to 3 mm particle size. The result is the division of sediment volume in sediment size classes that can be interpreted using grain-size parameters, histograms or cumulative curves.