Kenneth Pye Associates Ltd.
 Scientific Research, Consultancy and Investigations

              
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Clast Lithological Analysis and Mineralogical Analysis
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A number of different techniques, including optical, fluorescence and scanning electron microscopy, quantitative colour analysis, and x-ray diffraction analysis are used routinely to determine the provenance of rock and sediment particles and powders, and to assess differences and/or similarities between samples. In the case of samples containing gravel particles, different particle types can often be distinguished on the basis of simple properties such as overall shape, texture and colour. More detailed analysis involving examination of thin sections and various forms of mineralogical and chemical analysis, may be required to fully characterise each particle type. Samples which contain predominantly sand and coarse silt are normally examined using a combination of microscopic techniques including scanning electron microscopy. Elemental analysis of individual particles is undertaken by electron microprobe analysis or x-ray microanalysis in the SEM. The bulk mineralogical composition of sands, silts and clays is most commonly determined by x-ray powder diffraction.

    
Comparison of gravel particle types at           Major pebble clast types collected from Wicklow Beach, Ireland
two locations of interest in a smuggling           (picture width c. 18 cm)
investigation (picture width c. 10 cm)

An assemblage of rounded fine gravel particles from a marine beach in eastern Fuerteventura,
Canary Islands

    
X-ray diffraction curves for a London Clay                Bulk mineralogical composition of the <150 µm
sample, with minerals identified using different            fraction of a soil sample from Devon, UK
pre-treatments

Publications

Pye, K. (2007). Geological and Soil Evidence: Forensic Applications. CRC Press, Boca Raton, 335 pp.

Kenneth Pye Associates Ltd. - Environmental Consultants
Page last modified: July 11, 2007