摘要：Soil is a valuable resource in many criminal cases. Used to link crime scenes, suspects, vehicles and tools, it has undergone a resurgence in recent years with multiple groups focusing on methods to allow for better differentiation. Many times the methods are focused on soil fractions, such as the clay or organic fractions. However, very sandy soils, such as the quartz sands of the Swan Coastal Plain, present a challenge to these methods. Clays and organic materials are very limited in these soils and hence, another characteristic needs to be added to the examination process. The authors here present a potential technique useful for the differentiation of soils where the soil texture is dominated by quartz sand. The quartz sand grains are used as a sampling medium, where the fine coatings (particles <20 μm in size) are recovered and analysed using X-ray diffraction (XRD). The peak intensities for a total of 7 commonly occurring minerals, converted to relative percentages, were used to compare 52 sub-surface soils from known locations, and a further 339 soils from various stratigraphies, based on an algorithm for examining similarity. Results indicate this technique allows a degree of discrimination sufficient for inclusion in a standard soil comparison protocol, specifically for cases where the traditional fractionated analyses are not appropriate.
