FORENSIC GEOLOGY: “ALL THAT REMAINS ARE THE REMAINS”

The ability to conduct an exhumation and post-burial autopsy on human remains is crucial in circumstances where the cause/manner of death or other factors such as the identity of the deceased may remain uncertain and controversial. During an exhumation, three classes of potentially informative materials may be recovered: tissue samples, skeletal remains and/or associated artifacts (projectiles, embalming materials, clothing, etc.) Post-burial preservation of these materials is controlled by many inter-related natural and anthropogenic factors. Before undertaking an exhumation for forensic purposes, one must be as certain as possible that the state of preservation of the materials will be sufficient to shed new light on the reasons for the exhumation. Such a prediction is needed to assess the overall feasibility of the project and to guide the design of the exhumation/excavation plan. Forensic geology plays an important role in such feasibility studies on the possible taphonomic effects occurring since burial. The natural factors controlling preservation include elapsed time since burial, the climate, as well as the topographic and geologic conditions at the burial site. Among those to be considered are soil moisture, soil pH, porosity and permeability of the soil, hill slope, depth to water table, composition of soil and bedrock, vegetation and insect and subterranean animal ravaging. The anthropogenic factors relate directly to the nature and manner of the burial, such as the embalming protocol, type of clothes/wrapping, casket utilized, the presence of a burial vault and the depth of burial. Case studies with time of burial from 11 months to 150 years will illuminate the relative importance of these variables.