Radiocarbon dating of prehistoric hearths in alpine northern Sweden: problems and possibilities

The chronology of prehistoric Sami settlement sites has previously been established by conventional radiocarbon dating of bulk charcoal samples associated with hearths from sunken hut floors (stállo-foundations). Here we present results of a comprehensive dating exercise of stállo-foundations in the alpine area of northern Scandinavia using Accelerator Mass Spectrometry (AMS) radiocarbon dating of charcoal. Over a 3 km² study area, AMS calibrated ages of hearth charcoal from 22 stállo-foundations across 12 sites securely date these features to between cal. AD 640 and AD 1180. Only small variations in age were found between charcoal samples from different areas of a given hearth. Statistical analysis of all the charcoal AMS radiocarbon dates obtained reveals that 12 stállo-foundations across nine sites are contemporaneous and date to the Viking Period (AD 800–AD 1050). The tightly constrained AMS-based chronology of stállo-foundations contrasts with the existing chronology based on conventional radiocarbon analysis, which places these features within a significantly greater time-frame of between AD 600 and AD 1900, with most dates ranging between AD 800 and AD 1350.This discrepancy is likely to result from the necessity of collecting composite hearth charcoal particles, which may originate from different phases of occupation, in order to achieve the required final carbon content for conventional radiocarbon analysis. We argue that the new AMS-based radiocarbon chronology of stállo-foundations presented here supersedes the existing chronology based on conventional (Gas Proportional counting) radiocarbon analysis and we advocate the use of AMS radiocarbon dating in future hearth investigations.     

Phytolith evidence for hearths and beds in the late Mousterian occupations of Esquilleu cave (Cantabria,Spain)

Esquilleu cave site has provided a moderately well preserved archaeological cave deposit from the Late Pleistocene in the Cantabrian area. Phytolith quantification, identification and determination of the refractive index have been carried out, together with FTIR analyses, from sediment samples collected in the profile. The comparison of the data obtained with the previous micromorphological results allows us to make inferences about the site formation processes and the Neanderthals use of the cave. Phytolith results show the presence of grass leaves nearby the hearth suggesting the repetitive existence of a bedding zone on the same area. Neanderthal behavioral patterns should be revised on the light of high resolution analyses, since diagenetic processes can obscure the existence of differentiated activity areas in the site.     

On stone-boiling technology in the Upper Paleolithic: behavioral implications from an Early Magdalenian hearth in El Mirón Cave,Cantabria, Spain

Stone boiling is one of the principal cooking methods used by hunter-gatherer societies. The present paper proposes behavioral and organizational inferences as to how stone boiling was incorporated into hunter-gatherer subsistence practices through an examination of a shallow-basin hearth in an Early Magdalenian level (c. 15,500 ¹⁴C B.P.) of El Mirón Cave, Cantabria (northern Spain). Exploratory analysis of spatial patterns of archaeological remains (bones, lithic artifacts, and fire-cracked rocks) and use-life analysis of fire-cracked rocks demonstrate that the hearth was used and maintained during visits of humans who preyed mainly on ibex and red deer near the site. The relative accessibility of these ungulates and cost-induced technology of stone boiling suggest the implication that stone boiling was employed to maximize the energy and nutrition obtained from carcasses of these game taxa under the circumstance of resource intensification.     

Examining histology to identify burned bone

Early research suggests that examination of the microscopic internal structure is a valid method for distinguishing burned from unburned bone in the archaeological record. This study compares burned and unburned modern bones with archaeological bones from Sibudu Cave (ca. 60,000 years ago) and Cave of Hearths (over 200,000 years ago) to more fully describe the heat-induced histological changes to bone. We also explore the effects of diagenesis on those changes to determine if histological evidence of burning preserves through fossilisation and diagenetic processes and can be successfully used to identify ancient burning. Application of this technique can help in addressing various issues, including the origins of controlled use of fire and understanding animal butchery and disposal.     

A new approach to study the fuel used in hearths by hunter-gatherers at the Upper Palaeolithic site of Abri Pataud (Dordogne,France)

The fuel used in hearths in the Upper Palaeolithic period and the management of this fuel have long given rise to questions on intentional or opportunistic human comportment. To understand how fuel was managed during the Aurignacian and Gravettian cultures, hearth samples from the French site of Abri Pataud (ca. 34–20 kyr BP) were collected. An image analysis method for the automated quantification of burnt particles from macroscopic-to-microscopic sediment fractions was developed, and the results obtained using this method were compared with the palaeoenvironmental data available close to the site. At Abri Pataud, the use of bones was dominant during the Pleniglacial, suggesting an intentional practice. However, environmental pressures could have influenced the fuel management practices of the hunter-gatherers, even if the dualistic relationship between the availability of firewood and the use of bone in hearths must be considered. Thus, burnt particle quantification provides more than just an observation of burnt macroremains in hearths: it relates to fundamental information on human behavior.     

Accessing Hunter-Gatherer site structures using Fourier transform infrared spectroscopy: applications at a Taltheilei settlement in the Canadian Sub-Arctic

The results of Fourier transform infrared spectroscopy on soils and caribou bone from a Taltheilei culture settlement in northern Canada contribute to developing micro-archaeological approaches suitable for locating and characterizing hearth and midden features on hunter-gatherer sites. A weak yet pervasive signal for montgomeryite was developed from the diagenesis of dispersed ash and caribou processing residues. Disordered calcite, carbonate hydroxylapatite, charcoal, and burned bone in two pit-house hearth deposits indicate that both wood and bone were used for fuel. Crystallinity indices and carbonate/phosphate ratios for bone indicate high intensity burning. These data, in tandem with the presence of semi-subterranean dwellings, demonstrate that this particular tundra-based encampment was occupied during cold seasons, a type of settlement behaviour previously unrecognized in the Taltheilei archaeological record. Our results confirm that Fourier transform infrared spectroscopy is an accessible, rapid, and cost effective means of discovering micro-archaeological evidence valuable for reconstructing hunter-gatherer site structures.     

Digital imaging technology and experimental archeology: a methodological framework for the identification and interpretation of fire modified rock (FMR)

This paper presents the results of a series of experiments for the identification and analysis of fire modified rock (FMR). FMR is a common but frequently overlooked artifact type. Experiments were conducted simulating the effects of different hypothetical burning scenarios on rocks similar to those found in a South African Middle Stone Age site. A digital imaging method was then used to quantify FMR color values, designed to limit intra-analyst bias. Statistical tests and a blind test suggest that unburned rocks and experimental FMR can be separated statistically based on physical appearance. Two burning scenario models, based on measured experimental data were applied to archaeological FMR from a South African Middle Stone Age site named Pinnacle Point 5-6 (PP5-6) and show that the archaeological samples are not statistically different from a simulated campfire and possibly a lithic raw material heat-treatment fire.