True rate of destruction: Statistical evaluation of the impact of usage of sieves on fragmentation of burned human remains

Abstract

This study examines the secondary mechanical fragmentation of cremated human remains during the sieving process, a crucial aspect of bioarchaeological analysis. Originating from methodologies developed in the 1990 s, this practice involves passing cremains through a series of sieves with different mesh sizes (typically > 10 mm, >5 mm, and > 2 mm) to quantify the degree of fragmentation and generate numerical data for further statistical analyses. However, critics argue that this method may exacerbate the degradation of remains, potentially compromising valuable information, such as the original dimensions and the integrity of diagnostic features. These include fragments of cranial and pelvic bones that express sexual dimorphic traits and bone fragments essential for age-at-death assessment or fragments with paleopathological lesions. This study addresses the dearth of quantified data concerning the extent of fragmentation caused by sieving. Using Pearson’s correlation coefficients and generalized linear model, I assessed the secondary fragmentation resulting from sieving. The results confirm that sieving leads to additional fragmentation, irrespective of mesh shape, significantly affecting the total weight of the cremation context and the largest of the fractions separated by sieving (>10 mm). However, the overall weight loss from one or multiple sieving sessions is relatively modest. This is because the apparent reduction in weight is not solely due to the loss of osteological material but also to the redistribution of fragments into smaller size fractions. While sieving does contribute to fragmentation, it provides valuable insights into how cremains are affected by various taphonomic and cultural processes. To minimize data loss, the study recommends establishing methodological standards that include visual inspection and the selective exclusion of fragile fragments prior to sieving, thereby reducing secondary destruction of the cremains.