Taphonomic investigation into environmental effects on bone surface modifications.

Abstract

The current project investigated the extent to which taphonomic processes such as short-term exposure to the Biostratinomic effects of weathering and diagenetic effects of the soil matrix may alter or obliterate evidence of cutmarks on bones. It examined factors that may contribute towards bone degradation and therefore, cutmark degradation. There are a lack of multi- analytical methods and experimental data to support the hypothesis of the cross-linking ecological interactions and their direct damaging effect to bone, and consequent impact upon evidence of bone trauma and its identification. There is a need to understand how microenvironmental factors affect each other and how these ecological interactions may impact the longevity and survivability of the bone condition and therefore the cutmark condition. This research combines a review of existing literature with primary experimental data to determine if microenvironmental patterns can be distinguished and explore whether the changes to the different types of cutmarks could have a significance in a forensic investigation. Bladed instruments were used to inflict cutmarks upon the surface of Porcine bone; the bone specimens were deposited at a shallow depth and left on the surface of an identified hostile environment. The remains were removed bi-monthly and physical data from the cutmarks and geochemical data from the soil matrix were collected and analysed. Further observations were found regarding the effects of a hostile environment towards the cortical layer of the remains, that contradict the time frames of other studies and solidifies the hypothesis that damage to the bone surface from taphonomic modifications can occur in a shorter time frame and are local to the microenvironment. It has been found that there are previous unobserved phenomena on the remains specific to the physical appearance of the cutmarks. Specifically, there is a potential link between change in kerf width of the cutmark edge and physical changes to it as a result of the ecological interactions between the microenvironment and the cutmark on the bone found through digital and confocal microscopy. The level of activity for these changes such as the presence of macrofauna and microflora reflect upon the size and shape of the cutmark. This in turn impacts certain microscopic and scanning ‘wound-matching’ methods that have been investigated in the field of Forensic Science. It outlines that these methods should not assume that the dimensions of the cutmark accurately reflect the dimensions of the blade that was used to inflict said mark without consideration of the environment it was found in. This study has complimented and added to current research of how taphonomic changes may mimic, hide, or obliterate trauma on bone. From this the awareness of the influence from the abiotic and biotic microenvironmental effects and the associated ecological interactions will increase as a result of its contribution.