Analytical Methods for Assessing Preservation in Waterlogged Archaeological Wood : Their Importance for Site Management Decisions

Understanding and quantifying preservation of organic archaeological materials has become increasingly important as wet or waterlogged sites are put at risk from human-driven alterations, such as land drainage, urbanisation, and climate change. Although a wide range of analytical methods can be applied to assess the state of preservation of an archaeological object, determining which of these is most appropriate can be challenging. Within the budgets and deadlines dictated by the project design, an assessment must provide useful information that aids site management and conservation decisions. This review aims to summarise the most commonly reported methods suitable for the analysis of archaeological wood, offering an overview of the information obtained by each. Methods are evaluated in terms of the information gained weighed up against their cost, logistical considerations and time investments. Recommendations are provided to aid with the design of preservation assessment schemes

Multi-analytical characterisation of red colouration on decorated ostrich eggshells from the Middle Bronze Age in Bahrain

In the early 1960s, a Danish archaeological team excavated a group of mounds in Bahrain dating back to 2000 BC. Among their finds were fragments of decorated ostrich eggshells that displayed rectangular engravings as well as red colouring on the outer surface and a uniform red tint on the inner surface. The unpigmented natural coloration of ostrich eggs is the result of adaptations to prevent overheating in the arid habitat, and therefore, the red hue was artificial. The aim of this research was to characterise this coloration. Elemental analysis revealed low iron content, ruling out the use of iron-rich pigments such as ochre, while analysis by molecular spectroscopy could not detect any compounds besides the characteristic constituents of the calcareous eggshell. Thermal experiments on modern eggshells, combined with chiral amino acid analysis, indicated that the red colour on the archaeological samples could have been due to exposure to moderate temperatures. This investigation provides valuable insights into the art and cultural practices of ancient Middle Eastern societies during the Middle Bronze Age, contributing to our knowledge of prehistoric archaeology

An Integrated Approach to the Taxonomic Identification of Prehistoric Shell Ornaments

Shell beads appear to have been one of the earliest examples of personal adornments. Marine shells identified far from the shore evidence long-distance transport and imply networks of exchange and negotiation. However, worked beads lose taxonomic clues to identification, and this may be compounded by taphonomic alteration. Consequently, the significance of this key early artefact may be underestimated. We report the use of bulk amino acid composition of the stable intra-crystalline proteins preserved in shell biominerals and the application of pattern recognition methods to a large dataset (777 samples) to demonstrate that taxonomic identification can be achieved at genus level. Amino acid analyses are fast (<2 hours per sample) and micro-destructive (sample size <2 mg). Their integration with non-destructive techniques provides a valuable and affordable tool, which can be used by archaeologists and museum curators to gain insight into early exploitation of natural resources by humans. Here we combine amino acid analyses, macro- and microstructural observations (by light microscopy and scanning electron microscopy) and Raman spectroscopy to try to identify the raw material used for beads discovered at the Early Bronze Age site of Great Cornard (UK). Our results show that at least two shell taxa were used and we hypothesise that these were sourced locally

Palaeoproteomics resolves sloth relationships

The living tree sloths Choloepus and Bradypus are the only remaining members of Folivora, a major xenarthran radiation that occupied a wide range of habitats in many parts of the western hemisphere during the Cenozoic, including both continents and the West Indies. Ancient DNA evidence has played only a minor role in folivoran systematics, as most sloths lived in places not conducive to genomic preservation. Here we utilize collagen sequence information, both separately and in combination with published mitochondrial DNA evidence, to assess the relationships of tree sloths and their extinct relatives. Results from phylogenetic analysis of these datasets differ substantially from morphology-based concepts: Choloepus groups with Mylodontidae, not Megalonychidae; Bradypus and Megalonyx pair together as megatherioids, while monophyletic Antillean sloths may be sister to all other folivorans. Divergence estimates are consistent with fossil evidence for mid-Cenozoic presence of sloths in the West Indies and an early Miocene radiation in South America