CASE STUDIES IN FORENSIC PETROGRAPHY

Petrography is a common tool for geological applications, particularly in the oil, gas, water, and industrial mineral economic industries. However, since the 1940s petrography has found a niche outside the traditional economic geology fields by providing a valuable tool for identifying a variety of cause and effect relationships with constructional materials. In the engineering field, petrography is useful in understanding the behavior of concrete and concrete-making materials; determining cause(s) of structural concrete deterioration through identifying relationships between certain chemical components of cement hydration and potentially reactive aggregates; identification of engineered materials and cause(s) of distress; and identification of potential aggregate sources through comparative petrographic analysis. The results of such petrographic investigations are frequently employed as evidence in engineering-related court cases. Additionally, forensic petrography can provide vital information in personal injury cases to identify the source of a material and in capital murder cases where physical evidence is characterized and related to the crime scene. While a common tool for geological applications, petrographic examination has also become an indispensable tool for engineering purposes, as well as in civil and criminal court cases.