Tracking changes in bone fracture morphology over time: environment, taphonomy, and the archaeological record

Zooarchaeologists have often employed studies of bone fracture morphology as a means of understanding past human cultural activity, and various methodological approaches have been developed for analyzing archaeological broken bone assemblages. It is widely understood that bones degrade over time, however, few studies have attempted to define and quantify the rate at which bones degrade and fracture morphologies change. This study examines degradation in frozen bones (−20 °C) and bones exposed to hot (40 °C) dry conditions. These two simulated environmental conditions represent extreme real-world climates, and allow for an actualistic understanding of the rates of degradation that bones experience in nature. When frozen, bones degrade slowly but significantly, and demonstrate measurable differences in samples frozen for 1, 10, 20, 40, and 60 weeks. In hot, dry conditions, bones degrade very quickly, and demonstrate measurable differences after 1, 3, 7, 14, and 21 days. These data allow for a more detailed understanding of the relationship between the cultural and natural processes that result in bone fracture, and the time period during which bones can be expected to maintain fresh fracture characteristics. This research also has implications for understanding human subsistence and survival strategies and for interpreting the archaeological record.     

Possible evidence of bone tool shaping by Swartkrans early hominids

Ever since Dart (J. Phys. Anthrop. 7 (1949) 1) interpreted certain bones from Makapansgat as tools, scientific consensus has fluctuated as to whether some bone objects from early hominid sites should be interpreted as artefacts, or the result of non-human taphonomic processes, which are known to produce pseudo-bone tools morphologically similar to human modified or used artefacts. Here we present possible evidence of bone tool shaping from Swartkrans (Members 1–3; ca. 1.8–1.0 Mya). Four horncores and the proximal end of an ulna used as tools in digging activities also have facets covered by parallel spindle-shaped striations characteristic of grinding. Identification of these traces as possibly resulting from deliberate shaping or re-sharpening of the bone tools is based on the characterisation of the use-wear pattern and other taphonomic modifications observed on the Swartkrans bone tools. This interpretation is also supported by the study of the remainder of the horncores from Swartkrans, horncores from other southern African Plio-Pleistocene sites (Sterkfontein, Makapansgat, Gondolin), modern horncores affected by pre- and post-mortem modification, ethnographic, LSA, African Iron Age and experimental bone tools shaped by grinding. These data suggest that early hominids had the cognitive ability to modify the functional area of bone implements to achieve optimal efficiency.     

Lapita subsistence strategies and food consumption patterns in the community of Teouma (Efate,Vanuatu)

The subsistence strategies of the Lapita populations (3100–2800 BP), the first colonisers of the pristine environments of the islands of Eastern Melanesia and Western Polynesia, have been a matter of ongoing debate for decades. Opinions have ranged between the two extremes of Lapita colonisers being either characterised as highly mobile foragers to fully horticultural communities. To further address the question, this paper presents stable carbon and nitrogen isotopic data obtained from analyses of human and animal collagen samples from the site of Teouma (Efate, Vanuatu) dated to between c. 3000–2500 BP. The isotopic signatures obtained from 28 samples (23 human and 5 animal), interpreted in combination with isotopic information from several coastal and insular environments, suggest a diet primarily made up of terrestrially derived animal protein with lesser contributions from vegetable produce and inshore marine species. Comparisons linking the isotopic data gleaned from the Teouma individuals and Lapita subsistence patterns reconstructed through archaeozoological and archaeobotanical remains support the hypothesis of a mixed economy, that included terrestrial foraging, inshore marine exploitation and a low level of food production for at least some of the earliest Lapita colonists in Vanuatu.     

Introducing δSr analysis in archaeology: a demonstration of the utility of strontium isotope fractionation in paleodietary studies

Isotopic methods are widely used in archaeology to investigate paleodiet. Here, we present a new method to identify trophic level in archaeological human populations and to investigate paleodiet. We demonstrate that strontium isotope compositions (reported as δ^88/86Sr) vary in a mass-dependent manner with increasing trophic level and can elucidate paleodiet in archaeological human populations. We present new mass-dependent strontium isotope data from tooth enamel and bone from individuals buried during the Late Intermediate Period (c. AD 1000–1300) in the large cemeteries of Chiribaya Alta, Chiribaya Baja, San Gerónimo, and El Yaral in the Ilo and Moquegua Valleys of southern Peru. We compare these data to radiogenic strontium isotope data (⁸⁷Sr/⁸⁶Sr) and light stable isotope data (δ¹⁵N_col and δ¹³C_col) from the same individuals to investigate geologic variability in strontium sources as well as marine food consumption among the Chiribaya. Our results demonstrate the utility of measurements of strontium isotope fractionation as a new tool for archaeological investigation of paleodiet. Importantly, this new technique can be used to generate paleodietary (δ^88/86Sr) and paleomobility (⁸⁷Sr/⁸⁶Sr) data from the same specimen, minimizing destructive analyses of invaluable archaeological material, and provides a new way to examine paleodiet through hydroxyapatite, which is particularly important when collagen is poorly preserved.     

Cross-cultural interaction on Wuvulu Island,Papua New Guinea: the perspective from use-wear and residue analyses of turtle bone artifacts

Recent studies have emphasized the importance of Indigenous producers and traders in the formation of ethnographic museum collections, but have found difficulty in finding concrete evidence for their active roles. A use-wear and residue study of turtle bone cleavers from Wuvulu Island, Papua New Guinea provides the opportunity to test whether objects that comprise a significant component of early collections were made specifically for sale, as hypothesized by contemporary observers in the late 19th century. Comparative studies of used and unused turtle bone artifacts from the Caroline Islands and Papua New Guinea identified differences between wear traces resulting from manufacture and use. Analyses of the Wuvulu turtle bone cleavers showed they had been heavily used prior to sale. Rather than produce artifacts to meet the high demand from German traders, the local people sold old, worn-out objects, many of which had been repaired. The study demonstrates that archaeological approaches to ethnographic museum collections can trace Indigenous agency within cross-cultural interaction. It also showcases the potential of use-wear and residue analytical techniques for the analysis of bone tools and the utility of digital, hand-held microscopes for the analysis of large artifacts.     

Identifying the geochemical taphonomy of the osteological material from Katsambas rockshelter

We report analytical work undertaken in order to identify the geochemical taphonomy of the osteological collection (human and animal bones) recovered from a 1950s excavation at Katsambas, a small cavity in the marly limestone on the west bank of Kairatos River, Crete. The site had funerary use and yielded material of Neolithic and Minoan age with poor stratigraphical association. Disintegration of provenance labels from bags has introduced further uncertainty about the contexts of recovery. Samples of human and animal bones that macroscopically appear to belong to three taphonomic categories were studied by means of FT-IR spectroscopy, TEM microscopy and REE analysis to explore the taphonomical processes the bones have undergone. Although not novel in palaeontological research the use of REE opens a new path to investigating poorly provenanced osteological collections from old excavations. Such geochemical work offers a proxy to their relative dating through the evaluation of the time span bones have remained in the sediments and their respective taphonomic histories.     

Bone density studies in zooarchaeology

Accurate bone density data are essential for assessing the influence of destructive processes in archaeological faunal assemblages. Unfortunately, the diversity of methods employed by different researchers to derive density values has resulted in recent confusion. Two recent publications in this journal [J Archaeol Sci 29 (2002) 883; J Archaeol Sci 29 (2002) 979] exemplify this state of misunderstanding. Both studies argued that the role of bone density in shaping archaeological faunal assemblages has been largely overrated, but both based their conclusions on density values that were inaccurately derived. The former employed a method of calculating bone density that has been largely discredited over the past decade [J Archaeol Sci 29 (2002) 883]. Within a larger discussion of zooarchaeological methodology, the latter provided an assessment of the current state of bone density research that inappropriately characterized the discrepancies between available sets of density data as a reflection of the differences between two technologies—photon densitometry and computed tomography [J Archaeol Sci 29 (2002) 979]. The actual dichotomy exists—irrespective of the technology employed—between studies that account for variation in the shape of bone cross-sections and those that do not. The different sets of density data currently available to zooarchaeologists vary tremendously in their accuracy. We review and evaluate the different techniques employed in the research of bone density patterns of mammalian fauna. Computed tomography produces the most accurate density data. For elements without medullary cavities, photon densitometry may provide density values of similar accuracy but only if a method of cross-sectional shape-adjustment is applied.