The philosophy, nature and practice of forensic sediment analysis

The rapidly expanding field of forensic geoscience derives its roots from nineteenth- and early twentieth-century scientists who both influence and are influenced by literature and fictional writing. Forensic geoscience borrows much, but not all, of its precepts from geological and geomorphological analytical techniques. Fundamental differences exist between forensic geoscience and its sister disciplines, fundamental enough to make the unwary geoscientist succumb to philosophical and practical pitfalls which will not only endanger the outline of their report, but may well indeed provide false-negative or false-positive results leading to contrary or inaccurate conclusions. In the law, such outcomes have devastating and untenable consequences. Forensic geoscience requires techniques of exclusion rather than inclusion and an acknowledgement that analytical techniques may be diagnostic only in very specific situations. Whether analysis of the ubiquitous or the exotic component is chosen, acknowledgement of the need for samples to be representative is required. The presentation of false-positive results or the lack of identification of sample 'mixing' is prerequisite to the application of statistical tests which must be applied in the most careful manner. The realization of the limitations of the technique requires, wherever possible, conjunctive analysis by other truly independent techniques. While personal opinion derives from experience, there is no place for assumption. Research papers in forensic geoscience are not submitted to be speculative or challenging as may be the case in many fields of geomorphology and geology. There is no place for conjecture in forensic geoscience.