Geoarchaeology:Forensics

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Forensics
The role of archaeological techniques of investigation are well established within modern forensic science (Hunter et al, 1997). In combination with other archaeological science disciplines, geoarchaeology can make a valuable contribution to forensic study.

An understanding of soil type can help to explain or predict corpse preservation / decomposition. Likewise, an understanding of normal soil horizon sequences can be used to help identify areas of disturbance, reconstruct fill sequences and in "cold cases" even estimate time since burial based on the reformation of soil features and horizonation. The chemical analysis of soil materials can help to link soils found on a suspects clothes or shoes with a crime scene. Techniques such as multi-element analysis, petrology and X-ray microanalysis can provide information on the chemical compositions.

Sampling is of key importance in forensic geoarchaeology. The accuracy and significance of the findings have to be defendable against rigorous cross examination, and the consequences of getting it wrong can be devastating for the victim, their family and the accused. Sample size is often very small in forensic studies and often there will be no opportunities for replicate sampling. It is very important, therefore, that the variability of soil properties in potential source areas is fully understood. For example, soil taken from the show of a suspect may be a match for the soil from the crimescene but this is largely meaningless if all the soils in the area have a similar "signature". If however, the chemistry of the soil at the crimescene is distinctive it is much easier to build a case against the suspect. Likewise, a single soil sample from a crime scene may not match the soil from the suspects shoe if the chemistry of the soil is highly spatially variable. It is also important to remember that the chemistry of the sub-soil may be very different to that of the topsoil (Goldberg and Macphail, 2006). Accounting for this variability may involve taking multiple samples from each locality, and sampling from a range of localities in the region.

Analytical techniques
Click on the links below to find out more about some of the analytical techniques commonly used in forensic geoarchaeology.
 * Multi-element analysis
 * Micro-analytical X-ray analysis

Case Study

 * Prehistoric Clay Sources: A Forensic Exercise in Geoarchaeology.