Subaerial bone weathering and other taphonomic changes in a temperate climate

Thesis (M.S.)--Boston UniversityDetermining the postmortem interval in forensic cases becomes problematic at advanced stages when the decomposition of soft tissue ceases (generally less than six months) and radiocarbon dating cannot be applied (prior to AD 1950). Further research into bone weathering rates and patterns can aid in filling this large postmortem interval gap. Similar to soft tissue decomposition studies, the rate at which osseous weathering occurs needs to be studied regionally due to the significant effects of temperature fluctuations, sun exposure, and precipitation. This study investigates bone weathering rates and other taphonomic changes in New England. Other taphonomic changes that were investigated include carnivore scavenging patterns and tooth marks, rodent gnawing, and sources of color staining. The first part of this research was carried out in the White Mountain National Forest, NH on a sample of whole-carcass moose (Alces alces) deposited throughout the year due to vehicle collisions. Observations were made monthly and took place from December 2011 through October 2012. The second part of this research was conducted at the Boston University Outdoor Research Facility (ORF) in Holliston, MA on a sample of white-tailed deer (Odocoileus virginianus) long bones that were placed in three different microhabitats (grassland, wetland margin, and forest). Field observations took place from February 2012 through February 2013. The hypotheses being tested were that the rate of weathering is dependent on seasonality and that it will vary among different regions and between various microhabitats. In both the White Mountain National Forest, NH and Holliston ORF, weathering stage 1 was first observed five months after deposition. Advancement in weathering was greatest during the Fall and Spring months when temperature fluctuations above and below freezing occurred most frequently. At this time, the results from Holliston ORF indicate that microhabitat is not a statistically significant factor of osseous weathering when examined 50 weeks after deposition ( p=0.53). However, longer term data collection is needed in order to gather more meaningful information. Due to the short nature of this study in relation to weathering, this research will serve as a preliminary investigation and is intended to be carried out through the coming years