Time-since-death and bone weathering in a tropical environment

The structural breakdown of skeletal remains follows a lengthy decomposition process, progressing from the appearance of cracking along the bone to complete loss of shape and skeletal integrity, that can occur in as early as 6 years or as long as 30. The length of time a set of skeletal remains takes to decompose depends heavily upon its micro-environment, the local context in which decomposition agents act on remains. Critical changes in the micro-context can drastically increase or slow the process. The burial of remains below the surface has been found to effectively shut out many of the most destructive decaying agents, such as the natural elements and insect and animal activity. This causes an increase in the amount of time needed to breakdown the skeletal remains. A better understanding of the decomposition process in varying micro-contexts is important for the ability to correctly estimate time since burial. This can aid not only in understanding of archaeological remains, but also in the identification of individuals in modern forensic and human rights cases. This study details the observations made during the excavation and analysis of burials on the Isla de Coiba off the coast of Panama. The excavation took place during the summer 2003 in an effort to identify several individuals who were believed to be part of the 'disappeared', people who went missing and believed to have been murdered under orders by the Torrijos and Noriega military regimes. Through the fieldwork analysis a decomposition timeline, specific for the Coiba micro-environment, was created. This new set of stages can be used to estimate time since burial in other areas whose local context is similar to that found on Coiba.