Issues and opportunities in urban forensic geology

Abstract

Abstract Geological trace evidence including, for example, soil, sand and rock dust has been examined using a wide range of analytical techniques. Whilst such materials are common in rural locations, in urban areas, such geological materials are often perceived to be restricted to parks, recreational areas, gardens and waste ground. However, both geological materials and the wide range of analytical methods used to characterize them are much more applicable to the whole urban environment than is generally realized, with the main differences being the types and amounts of sample analysed and the methods adopted. The range of geological applications can be summarized as those deployed at the broad (decimetres–kilometres) to small (millimetres–decimetres) scale. The broad spatial variation in soil, roadway, water, buildings materials, and wind- or water-borne particles can be contrasted with the variation in urban materials from dwellings to streets or gardens and parks, along with the micro-spatial and stratigraphical variation in each. In addition, geological principles and techniques that have not been used before can be applied to urban materials to provide comparisons of material that were not previously achievable, or to add a further proxy to established methods. The latter point is demonstrated with a case study using X-ray diffraction and QEMSCAN® of a criminal case where building plaster with peculiar qualities could be compared between a suspect's vehicle and plaster present along the escape route from a murder scene.