Stable carbon and oxygen isotopic compositions of wood ash: an experimental study with archaeological implications

Wood ash, composed mainly of the mineral calcite, is an important component in many archaeological sites. Identification of wood ash in the archaeological record is often difficult due to mixing of ash with other calcitic components of geogenic origin and/or due to diagenetic changes. A recent empirical study using the stable isotope compositions of carbon (δ¹³C) and oxygen (δ¹⁸O) in wood ash enabled the identification of mixtures of wood ash with geogenic calcite and to follow diagenetic changes due to partial dissolution and re-precipitation of ash in two prehistoric cave sites in Israel. Little however is known about the processes responsible for the isotopic compositions of wood ash in relation to formation at various temperatures and the influence on isotopic composition of ash from a variety of plant species. Here we present an experimental study of wood ash formed by burning three C3 tree species and one C4 desert bush at different temperatures. The results indicate that there are significant differences in the isotopic compositions of carbon and oxygen between wood ash that forms by combustion at a relatively low temperature (500 °C) and at a higher temperature (900 °C). In addition, we show that the isotopic composition of carbon and oxygen in high temperature wood ash approaches equilibrium over a period of several months and that the carbon isotopic composition of low temperature wood ash may reflect the photosynthetic pathway of the burnt woody species. Lastly, we show that the isotopic compositions obtained from wood ash prepared at different temperatures do not reflect a temperature dependent fractionation process, but a mixing line between calcite that formed by low temperature combustion and calcite formed by high temperature combustion which later underwent re-carbonation with atmospheric CO₂. In addition, we suggest that exchange processes may possibly occur during combustion between decomposing calcium-oxalate and atmospheric O₂, CO₂ and CO. The archaeological implications of this study are discussed in relation to identification of wood ash in the archaeological record, identification of fuel sources and burning temperatures, and diagenetic changes expected in karstic cave environments. The method presented here can be applied at any archaeological site.     

Living and dying as subjects of the Inca Empire: Adult diet and health at Puruchuco-Huaquerones,Peru

Imperial strategies varied as the Inca expanded their empire from the capital in Cusco. Some communities were conquered violently while others were ruled indirectly with little evidence of Inca presence. According to ethnohistorical evidence, the central coast was peacefully annexed by the Incas ca. A.D. 1470, but little is known about how Inca imperialism may have affected the quality of life of subjects of the Inca Empire. We integrate multiple lines of evidence to assess diet, health and disease for a sample of human remains from the Late Horizon cemetery of Puruchuco-Huaquerones, Peru. Specifically, we examine and analyze osteological, dental and stable isotope data (n = 162, 90 and 46 respectively) in order to investigate whether the Inca period population at Puruchuco-Huaquerones experienced nutritionally insufficient diets and poor health under imperial policies. Diet at Puruchuco-Huaquerones incorporated a variety of foods, both plant and animal. Osteological lesions and stature indicate periods of stress, with males experiencing more illness relative to females. Stature sexual dimorphism, the presence of healed lesions and isotope data indicate a sufficiently nutritious diet and support the conclusion that, although disease was present, individuals were healthy enough to survive and recover. Geographical and temporal comparisons suggest that health changed little with the Inca annexation of this region, but future work is needed.     

Discerning geological and geographical sources of Belgian Upper Paleolithic fluorites by rare earth elements and Sr-isotopic geochemistry

Fragments of fluorite (CaF₂) have been found at five Belgian Upper Paleolithic sites (Spy, Chaleux, Trou Magritte, Trou du Frontal and Verlaine caves), primarily of Magdalenian age. These sites are located in a large geographical area. The aim of this study is to isolate one or more primary sources where the mineral could have been quarried prehistorically, and hence try to deduce if time and effort were put into obtaining it, or if it was simply a useful nearby raw material. In order to achieve this objective, isotopic ⁸⁷Sr/⁸⁶Sr and REE ratios are used. A total of four archaeological samples from the Chaleux, Spy and Trou Magritte sites along with geological samples were analyzed (new results and data from the literature), obtained from two distinct stratigraphical units in Belgium: the Givetian limestones (mainly from the Calestian Band), and the Dinantian limestones.     

Isotopic evidence of dietary variability in subadults at the Usu-moshiri site of the Epi-Jomon culture,Japan

This study reconstructs adult and subadult diets of a hunter-gatherer population of the Epi-Jomon culture (approximately 2300–1700 years BP) in Japan, using the stable isotopic analysis of carbon and nitrogen. The results suggest that the Usu-moshiri adults were highly dependent on marine resources such as seals for their dietary protein intake and that no significant dietary differences existed between the sexes. Among subadults we found two types of diet on the basis of different isotopic signatures. One group consisted of individuals with δ¹³C values below than those of the adult female mean minus two standard deviations and δ¹⁵N values lower than those of subadults in the other groups. These low-δ¹³C subadults indicated relatively less enriched δ¹⁵N values by 3.5 years of age at the latest. They probably consumed more ¹³C-depleted foods during weaning than in the ordinary adult diet. In the other high-δ¹³C group, their enriched δ¹⁵N values start to decline by four years of age and fall within the two-standard-deviations range of the total adult mean around five to six years of age. Isotopic values of children in this high-δ¹³C group suggest that they would have been fed ordinary adult diets during weaning. Perinates could also be divided into two groups on the basis of the similar patterns in their carbon and nitrogen isotope ratios. Our results indicate variabilities in the diets of subadults, and similar variabilities were also seen in ethnographic studies of the Ainu populations.     

Palaeolimnological impacts of early prehistoric farming at Lough Dargan,County Sligo,Ireland

This study provides a unique method of inquiry for archaeological investigation with an aim to assess the intensity and effects of Neolithic and Bronze Age farming practices at Lough Dargan, northwest Ireland, through a multi-proxy analysis of a lake sediment core. Chironomid (non-biting midge fly) subfossils and lake sediment geochemistry (δ¹³C, δ¹⁵N and C:N ratios) were used to assess changes in limnological conditions through time. The limnological data were compared with macroscopic charcoal concentration and pollen data to examine the potential influence that early farmers had on a freshwater lake system within a prehistorically active catchment. Results from the chironomid analysis show that the first substantial period of agricultural activity in the early Neolithic (c. 3730–3190 BC) resulted in a temporary shift to more eutrophic lake conditions. There is evidence of animal husbandry with substantial levels of animal waste reaching the lake, leaving an imprint in the geochemical record of increased δ¹⁵N values and decreased δ¹³C values and C:N ratios during this time. The chironomid community reverted back to its pre-impacted state c. 3190 BC in response to a period of reduced farming (c. 3390–3000 BC) which eventually led to a distinct lull in activity, with possible cessation of farming from 3000 to 2700 BC. A return to eutrophic conditions coincided with the gradual return of agriculture, with more permanently altered lake conditions dominating from 2400 BC, even during a 250-year period of reduced human activity commencing at c. 1440 BC. Increased sedimentation rate, along with increases in δ¹³C, δ¹⁵N and C:N, the presence of chironomid taxa indicative of erosion, more eutrophic lake conditions and high concentrations of macroscopic charcoal all point to more intensive land use practices during the Bronze Age. Palaeolimnological data exhibited an immediate response to intensified farming during this time, and were especially responsive to pastoral farming due either to scale of activity or proximity to the lakeside. The success of this study demonstrates the effectiveness of palaeolimnological analysis in the investigation of prehistoric farming. This approach will help inform Neolithic and Bronze Age land-use practice and human–environment relations in the region, and highlights the potential for chironomid-based archaeological research.     

Birdmen, cemís and duhos: material studies and AMS C dating of Pre-Hispanic Caribbean wood sculptures in the British Museum

This paper presents 19 AMS radiocarbon dates from nine pre-Hispanic Caribbean (Taíno/Lucayan) wooden sculptures in the British Museum collections, provenanced to Jamaica, Hispaniola and the Bahamas. Together with strontium isotope results and wood and resin identifications, these data build a material and chronological context for some of the most recognised examples of Taíno art – from duhos (ceremonial seats) and cemís (free standing depictions of deities, ancestors and spirits) to canopied stands used to hold hallucinogenic drugs during the cohoba ceremony. Each sculpture widens our understanding of Caribbean carving traditions, stylistic variation, chronologies and material resource utilisation. A group of three sculptures recovered from Carpenters Mountains, Jamaica, carved by AD 1300 and brought together as a ceremonial ‘set’, each appear to have had their inlays renewed over a century later, suggesting long-term use. Three key examples of the main Caribbean duho categories (high-back, low-back and extended), provide insights into the diversity of styles present in the region post-AD 1100. The British Museum's corpus enables an exploration of regional styles, and potentially the work of individual artists.     

A Late Bronze Age Shipwreck with a Metal Cargo from Hishuley Carmel,Israel

A 13th‐century‐BC shipwreck site, Hishuley Carmel, is described and discussed. It provides direct evidence for marine transport of copper and tin along the Israeli coast and may indicate inland and maritime trade‐routes of metals in the Mediterranean. The shipwreck represents a supply‐system providing the demand for bronze in the Levant. Trace‐elements and lead‐isotope analysis suggest that the copper came from Cyprus, similarly to bun and oxhide ingots from Uluburun. The source of the tin cannot yet be ascertained. The medium‐size ship was probably grounded and wrecked during a storm. Some of the cargo may have been salvaged in Antiquity. © 2012 The Authors     

A Late Neolithic vertebrate food web based on stable isotope analyses

Stable carbon and nitrogen isotope analyses of bone collagen, and stable carbon and oxygen isotope analyses of the bone's structural carbonate, were performed on 120 individuals representing 33 vertebrate species, including a single human bone find, collected from the Late Neolithic settlement at Pestenacker, Bavaria, Germany. We were thus capable of reconstructing a rather complex food web and could also address particular issues, such as whether humans influenced the diet of their domestic animals as opposed to their wild relatives, or whether humans perhaps had to compete over food with their domesticates. A rather unexpected result was that freshwater fish, which could be captured in the nearby river Lech, a major tributary of the Danube, contributed to the human diet only occasionally. As for mammals, it was also possible to recognise different trophic levels for birds and aquatic vertebrates, applying stable isotope analyses to both bone collagen and structural carbonate. In the case of fish, δ¹⁸O values at least revealed a physiological regularity in terms of temperature preference, besides diet. Conceivably, variability of δ¹⁸O in surface water as reflected, for example, by species that avoided human settlements, may help to characterise past ecosystems and to define site catchment exploited by Neolithic man in the course of food acquisition. Copyright © 2006 John Wiley & Sons, Ltd.     

Frontiers of Contact: Bioarchaeology of Spanish Florida

The arrival of Europeans in the New World had profound and long-lasting results for the native peoples. The record for the impact of this fundamental change in culture, society, and biology of Native Americans is well documented historically. This paper reviews the biological impact of the arrival of Europeans on native populations via the study of pre- and postcontact skeletal remains in Spanish Florida, the region today represented by coastal Georgia and northern Florida. The postcontact skeletal series, mostly drawn from Roman Catholic mission sites, are among the most comprehensive in the Americas, providing a compelling picture of adaptation and stress in this setting. Study of paleopathology, dental and skeletal indicators of physiological stress, stable isotope (carbon and nitrogen) analysis, tooth microwear, and skeletal morphology (cross-sectional geometry) reveals major alterations in quality of life and lifestyle. The bioarchaeological record indicates a general deterioration in health, declining dietary diversity and nutritional quality, and increasing workload in the contact period. The impact of contact in Spanish Florida appears to have been more dramatic in comparison with other regions, which likely reflects the different nature of contact relations in this setting versus other areas (e.g., New England, New France). The bioarchaeological record represents an important information source for understanding the dynamics of biocultural change resulting from colonization and conquest.     

Origin of deep saline groundwaters in the Vienne granitic rocks (France): constraints inferred from boron and strontium isotopes

As part of a preliminary geological characterization programme to assess the feasibility of an underground laboratory in granitic rock, a series of 17 deep boreholes (maximum depth, 900 m) was drilled by ANDRA in the Vienne district, France. A salinity gradient was demonstrated in the granitic waters with concentrations varying from approximately 1 g L^?1 at 150 m depth at the top of the basement (beneath the sedimentary cover) to 10 g L^?1 in the deeper part (from 400 to 600 m depth). Sr and B isotope ratios were measured in order to better understand the origin of the salinity and to evaluate the degree of water–rock interaction in the system. The results obtained were compared to those of mineral spring waters emerging from the granitic basement in the Massif Central. Evidence in support of a significant marine contribution include: (i) the Cl–Br investigations agree with a marine origin for the saline groundwaters without evolution from seawater; (ii) the ⁸⁷Sr/⁸⁶Sr ratio of the Vienne deep groundwaters (0.7078–0.7084) is in agreement with a palaeo‐seawater isotopic signature; (iii) measured δ¹¹B values for the deepest brine samples are enriched in ¹¹B (up to 36.1‰) relative to the granitic springs. The combined use of δ¹¹B, Cl, B, Br, Sr contents and ⁸⁷Sr/⁸⁶Sr ratios makes it possible to define and quantify a mixing model between marine and crustal end‐members in order to explain the origin of the deep saline groundwaters in the Vienne granitic rocks.