Grain size distribution

The Sedimentology laboratory of the GeoLab has a Malvern Mastersizer 2000 particle sizer.

The Mastersizer 2000 uses the technique of laser diffraction to measure the grain size distribution of a sample of loose grains. It does this by measuring the intensity of light scattered as a laser beam passes through a sample of dispersed grains. These data are then analyzed using both the Mie and the Fraunhofer light theory to calculate the size of the grains that created the scattering pattern. The range of the instrument is 0.01–2,000 μm.

The grain size distribution of a sample can be determined on bulk samples or on insoluble residues after chemical pretreatments (carbonate-free and/or biogenic silica-free residues). Organic matter may also be removed chemically. The decision on whether a given sediment fraction should be removed depends on the research question. The bulk grain size distribution of a sample can only be determined using the laser particle sizer if the sample consists of loose grains smaller than 2 mm. If a sample is cemented, then the cement needs to be removed chemically, but this is not always possible (e.g. quartz cements).


Scientific advisor