Intensive El Niño and the Iron Age of South-eastern Africa

Burnt daga structures in Iron Age villages serve as proxies for severe drought on the plateau of southern Africa. The distribution of burnt daga remains in two other rainfall areas, KwaZulu-Natal and the Inter-Tropical Convergence Zone over Zimbabwe, Zambia and Malawi, establishes a sequence of simultaneous burnings that parallels the severe droughts recorded for the interior plateau. These widespread correspondences suggest a common cause. Another correspondence with natural proxy data from South America indicates that intensive El Niño events most likely caused the droughts.     

Soil geochemistry and detection of early Roman precious metal and copper alloy working at the Roman town of Calleva Atrebatum (Silchester,Hampshire, UK)

A geochemical soil survey was carried out over 500 m² of a first and second century AD house complex in insula IX of the Roman town of Calleva Atrebatum (Silchester, Hampshire, UK) where there was little prima facie evidence for non-ferrous metalworking. Preliminary analyses were made by XRF of lead, zinc and copper. These were followed by analysis for Au, Ag and Sn by ICP-MS of the samples with the highest concentrations of Pb, Zn and Cu. Certain of the Pb, Zn and Cu concentrations suggest the working of copper alloy including brass, and could be associated with archaeological evidence of hearths and burnt areas of second century AD date. Other samples have concentrations of the above metals and of gold and silver which do not appear to be associated with any physical remains of hearths and burnt areas. These concentrations date to the mid-first century AD.     

Species specific marine radiocarbon reservoir effect: a comparison of ΔR values between Patella vulgata (limpet) shell carbonate and Gadus morhua (Atlantic cod) bone collagen

A number of recent studies of the UK coastal environment have assessed the ¹⁴C marine radiocarbon reservoir effect (MRE) via quantification of ΔR values for several periods throughout the Holocene using marine mollusc shells. However, none have employed fish bone as the marine sample, and the importance of being able to use this material as a reliable dating tool is evident when considering the boom in the British fish trade during the first millennium AD, the so-called ‘fish event horizon’, and the corresponding volume of fish remains that appear in the archaeological record from this time. This study compares ΔR values derived using the multiple paired sample approach employing burnt cereal grain (Hordeum sp.) as the terrestrial sample and either fish bone [North Sea cod (Gadus morhua)] or marine shell [limpet (Patella vulgata)] as the marine sample. The results show a general trend of increasing ΔR for the fish bone compared to shell, however, the differences are not statistically significant when the standard error for predicted values is used as the measure of variability in the ΔR values.     

The use of radiocarbon-derived ΔC as a paleoclimate indicator: applications in the Lower Alentejo of Portugal

Values of δ¹³C are frequently reported with radiocarbon dates from organic materials. In C₃ plants δ¹³C values have been linked to changes in water use efficiency as a response to arid conditions. By calculating ¹³C discrimination (Δ¹³C) from ¹³C isotopic composition (δ¹³C), archaeologists can gain potentially valuable inference into past climate conditions. Values of Δ¹³C reflect the process of discrimination against heavier ¹³C isotopes of carbon by comparing the δ¹³C of samples to that of the atmosphere, and can be calculated when records of atmospheric δ¹³CO₂ are available. The present study examines a 1300 year history of radiocarbon-derived Δ¹³C from the Lower Alentejo of Portugal using charcoal recovered from excavations of a series of medieval habitation sites in the study area. To calculate Δ¹³C, the posterior means generated from Bayesian change-point analysis of δ¹³CO₂ records were used. Archaeological data were then compared to contemporary ecological studies of Δ¹³C of the same taxa against instrumental records of climate. Values of Δ¹³C fell within mean ranges for the taxa through a period of population growth between the 7th and 10th centuries AD. During the height of the Medieval Warm Period in the 11th century AD Δ¹³C values frequently fell to low levels associated with arid conditions. At this time environmental degradation and erosion were documented. Values of Δ¹³C increased for a brief period in the early 12th century AD before the rural Lower Alentejo was largely abandoned for nearly two centuries. Another period of aridity occurred in the 16th and 17th centuries AD. Radiocarbon-derived Δ¹³C is a potentially useful paleoclimate proxy for archaeologists provided that results can be paired with observed Δ¹³C variation in studies that pair these data with instrumental climate records.     

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.     

A lake fortress,a floating chronology,and an atmospheric anomaly: the surprising results of a radiocarbon wiggle-match from Āraiši,Latvia

An Iron Age timber settlement which, in view of the defensive structures uncovered, is described as a lake fortress, on an island in Lake ārai?i, north-eastern Latvia, was excavated in 1965–69 and 1975–79 by teams led by Jānis Apals, who distinguished five construction phases. Dendrochronological analysis produced a c. 100-year floating chronology for Norway spruce (Picea abies (L.) Karst.) timbers from the earliest phase. A ¹⁴C wiggle-match was undertaken to obtain an absolute date range for the final year of the floating chronology, and thus for the construction of the settlement. Ten blocks of wood from one timber, each comprising 6-11 years and collectively spanning the whole 93-year tree-ring series, were dated by AMS. Using the IntCal13 calibration data, there is a 95% probability that the felling date of this timber falls in the range 775–784 cal AD. It appears, however, that the AD 775 spike in the atmospheric ¹⁴C level occurred within the 6-year span of the last sample. On this basis, we can narrow the date of construction to 776–780 cal AD. This date is significantly earlier than those reported in previous publications.     

Stable isotope analysis of dog,fox, and human diets at a Late Holocene Chumash village (CA-SRI-2) on Santa Rosa Island,California

Stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope analyses of dog (Canis familiaris), island fox (Urocyon littoralis), and human bone collagen from CA-SRI-2 (AD 130–1830) on Santa Rosa Island, California provide a proxy of diet and the relationships between humans and these animals. Carbon isotopic signatures indicate that Native Americans and their dogs at CA-SRI-2 subsisted almost exclusively on marine resources, while the island fox ate primarily terrestrial foods. Nitrogen isotopes and archaeofaunal remains indicate that humans and dogs also ate higher trophic level foods, including finfishes, marine mammals, and seabirds with smaller amounts of shellfish. The CA-SRI-2 island foxes appear to have eaten higher amounts of terrestrial foods, similar to the diets observed in modern fox populations. These data generally confirm the commensal relationship assumed to exist between domesticated dogs and people, but the carbon isotopic composition of dogs is enriched ∼2‰ compared to humans. We hypothesize that the difference in carbon isotopes between dogs and humans may have resulted from a higher consumption of C3 plants with lower δ¹³C values by humans, or less likely from the ingestion by dogs of significant amounts of bone collagen, which is enriched by ∼4‰ over associated muscle.     

Chronostratigraphy of an Eroding Complex Atlantic Round House,Baile Sear,Scotland

A high-resolution chronostratigraphy has been established for an eroding Atlantic round house at Sloc Sàbhaidh (North Uist, Scotland), combining detailed OSL profiling and dating of sediments encompassing the main bracketing events associated with the monument, radiocarbon AMS dates on bone recovered from excavated features and fills within it, and TL dates on pottery and burnt clay. Concordant OSL and radiocarbon evidence place construction of the wheelhouse in the first to second centuries AD, contemporary with dates from the primary occupation. Beneath the wheelhouse, clay deposits containing burnt material, attest to cultural activity in vicinity to the monument in the preceding second to first centuries BC. At a later date, the southern wall collapsed, was rebuilt, and the interior spaces to the monument re-structured. The chronology for the later horizons identified from the sediment luminescence dates extends to the second half of the first millennium AD, which goes beyond the range of the radiocarbon dates obtained. The data from ceramics encompass both periods. The juxtaposition of the dating evidence is discussed relative to short and longer chronologies for this Iron Age monument. Corollaries of this research are the implications that based on the long chronology, some of the ecofacts (bone) appear to be residual, and that the temporal duration of Hebridean Coarse Ware may extend into the second half of the first millennium AD.     

Paleoenvironmental catastrophies on the Peruvian coast revealed in lagoon sediment cores from Pachacamac

Paleoenvironmental reconstruction combining data from diatom, pollen, macrophytic, and archaeological analyses had not been attempted previously for coastal Peru. We analyzed two radiocarbon-dated sediment cores extracted from the “sacred” Urpi Kocha Lagoon at the pre-Hispanic religious center of Pachacamac (ca. AD 350-1533), near Lima, to characterize the paleoenvironment of the site. The data reveal an environmental history characterized by alternating periods of severe drought and catastrophic flood. Recurrent pulses with distinctive sediment, diatom, pollen, and macrophytic characteristics reflecting variations in water depth, substrate, turbidity and salinity, usually contain a thick basal sandy storm deposit overlain by thin organic accumulations of peat, gyttja, and snails. The most intense of these disturbance pulses, when correlated with pollen, plant macrofossils, radiocarbon dates, and regional proxy data, provide local evidence of four major floods associated with sustained, catastrophic El Niño events, tsunamis and/or severe storms in the Andean highlands over the last 2000 years.     

Climatologies of semi-diurnal and diurnal tides in the middle atmosphere (70–110 km) at middle latitudes (40–55°)

The radars utilized are meteor (2), medium-frequency (2) and the new low-frequency (1) systems: analysis techniques have been exhaustively studied internally and comparatively and are not thought to affect the results. Emphasis is placed upon the new height-time contours of 24, 12 h tidal amplitudes and phases which best display height and seasonal structures; where possible high resolution (10 d) is used (Saskatoon) but all stations provide monthly mean resolution. At these latitudes the semi-diurnal tide is generally larger than the diurnal (10–30 m s⁻¹ vs. < 10 ms⁻¹), and displays less month to month variability. The semi-diurnal tide does show significant regular seasonal structure; wavelengths are generally small (⩽50 km) in winter, large in summer (≲ 100 km), and these states are separated by rapid equinoctial transitions. There is some evidence for less regularity toward 40°C. Coupling with mean winds is apparent. The diurnal tide has weaker seasonal variations; however there is a tendency for vertical wavelengths and amplitudes to be larger during summer months. On occasions in winter and fall wavelengths may be less than 50 km. Again the seasonal transitions are in phase with reversals of the zonal wind. Agreement with new numerical models is to be shown encouraging.     

Regional ecological variability and impact of the maritime fur trade on nearshore ecosystems in southern Haida Gwaii (British Columbia, Canada): evidence from stable isotope analysis of rockfish (Sebastes spp.) bone collagen

The maritime fur trade (1785–1840s) led to the local extinction of sea otters (Enhydra lutris) in many parts of the northeast Pacific. On the basis of studies of extant sea otter populations, it has been established that they have a disproportionate effect on nearshore ecosystems by limiting sea urchin abundance and facilitating the establishment of nearshore kelp forests; in the absence of sea otters, a local reduction in kelp-derived carbon is therefore expected. We measured the isotopic composition (δ¹³C and δ¹⁵N) of rockfish (Sebastes spp.) bone collagen from late Holocene archaeological sites in southern Haida Gwaii, BC, Canada, using δ¹³C as a proxy for kelp-derived carbon in the diet and δ¹⁵N as a proxy for trophic position. We observed significant spatial variability in rockfish kelp-derived carbon (δ¹³C), but not trophic level (δ¹⁵N). Kelp-derived carbon varied largely as a function of site characteristics (wave exposure), suggesting that local oceanographic conditions are important factors with respect to consumer tissue isotopic compositions. Kelp-derived carbon decreased in post-European contact rockfish relative to pre-European contact rockfish, likely as a result of the reduction of kelp forests associated with the local extirpation of sea otters. Although we detected a reduction in kelp-derived carbon in rockfish diets, we found no shift in trophic level at sites occupied following the maritime fur trade. This implies a shift in local ecosystems, and particularly in carbon sources, following the maritime fur trade, likely due to a trophic cascade resulting from the local extirpation of sea otters. Stability in rockfish trophic levels, however, implies that rockfish continued to feed at similar trophic levels, consuming prey with similar nitrogen isotopic compositions.     

Rare Types of Trephination from Hungary Shed New Light on Possible Cross‐cultural Connections in the Carpathian Basin

Symbolic or incomplete trephinations are very common in Hungary in 9^th–11^thcentury AD skeletal series connected to early Hungarians, although they also occur in the preceding Avar Age (6^th–9^th c. AD) material. During the compilation of a database of regional cranial modification data, the authors found rare almond‐shaped symbolic trephinations in both periods, while these had formerly only been reported in Early Hungarian series. In this study, the new almond‐shaped lesions are described along with other symbolic trephinations of 14 newly found skulls from the 8^th–11^thcenturies AD in the Southern Great Plain of Hungary. The authors review the research of the phenomenon. The new findings may strengthen the theory of direct and very close cultural connections of these two ethnic groups, adding a new aspect to the debate over the origin and relationship of Late Avar (late 7^th–early 9^th c. AD) and Early Hungarian (9^th–11^th c. AD) populations. Copyright © 2013 John Wiley & Sons, Ltd.     

The Emirate of Córdoba (756–929 AD) and the introduction of the Egyptian mongoose (Herpestes ichneumon) in Iberia: the remains from Muge,Portugal

We describe new finds of Herpestes ichneumon (Egyptian mongoose) from an archaeological context in Portugal, directly ¹⁴C dated to c. 800 AD. This is at least two centuries older than a previously reported find of this species from Andalusia (southern Spain; Riquelme-Cantal et al., 2008). Our finding provides further support to the hypothesis that the Muslims introduced this animal to the Iberian Peninsula. In particular, we suggest that Berber settlers might have brought it some time during the Umayyad conquest of Iberia or with the establishment of the Emirate of Córdoba.     

Stable isotopes in human skeletons of Southern Ontario: reconstructing Palaeodiet

Most native plants of Ontario use the C₃ photosynthetic mechanism and therefore have relatively low ${}^{13}\text{C}{}^{12}\text{C}$ ratios; maize is a C₄ plant and is relatively enriched in ¹³C. The proportion of maize in the diet of a human can therefore be estimated from the ¹³C-content of collagen of fossil bone. We have used this method to follow the increase in consumption of maize in ancient native populations over the interval from AD 400 to 1650, and to quantify the amount of maize consumed. Maize consumption rose gradually to a maximum of 50% of the diet by AD 1400. These data agree with archaeologically derived data for this region, and with previous isotope studies in the northeastern U.S.A. In some of the latter, however, the maximum percentage of maize consumed has been overestimated because maize was assumed to have a δ¹³C value of ?12·5‰; our studies of archaeological specimens show the correct value to be closer to ?9‰. The introduction of beans into the native diet about AD 1100, should have caused a decrease in the ¹⁵N content of human bone collagen because legumes are deficient in this isotope, with respect to meat and fish. However, we observe no significant change in the ${}^{15}\text{N}{}^{14}$N ratio of human bone collagen over the period from 2300 BC to AD 1640. We conclude that meat and fish remained the main sources of protein even after the advent of agriculture into this region.     

Detecting the medieval cod trade: a new method and first results

This paper explores the potential of stable isotope analysis to identify the approximate region of catch of cod by analysing bones from medieval settlements in northern and western Europe. It measures the δ¹³C and δ¹⁵N values of cod bone collagen from medieval control samples collected from sites around Arctic Norway, the North Sea, the Kattegat and the Baltic Sea. These data were considered likely to differ by region due to, for example, variation in the length of the food chain, water temperature and salinity. We find that geographical structuring is indeed evident, making it possible to identify bones from cod caught in distant waters. These results provide a new methodology for studying the growth of long-range trade in dried cod and the related expansion of fishing effort—important aspects of the development of commercialisation in medieval Europe. As a first test of the method, we analyse three collections of cod bones tentatively interpreted as imported dried fish based on a priori zooarchaeological criteria. The results tentatively suggest that cod were being transported or traded over very long distances since the end of the first millennium AD.     

Applying new approaches to modeling diet and status: isotopic evidence for commoner resiliency and elite variability in the Classic Maya lowlands

Classic Maya states were characterized by a high degree of socioeconomic stratification. This paper investigates the degree to which status, as defined by grave goods and tomb construction, influenced dietary patterns of elites and commoners throughout the Classic Period (200–900/1000 AD) of the southern lowlands. We compile a database (N = 102) of previously-published stable isotope ratios (δ¹³C collagen, δ¹³C apatite, and δ¹⁵N collagen) from Maya bone mineral and collagen, and interrogate these data through two new isotopic modeling techniques: a simple carbon isotope model ( Kellner and Schoeninger, 2007; Froehle et al., 2010) and a multivariate isotope model ( Froehle et al., 2012). We find that Maya elite diet varied significantly through time in terms of maize consumption and trophic level, while commoner diet remained remarkably stable. These findings provide new information relevant to studies of ancient Maya class structure and to studies of subsistence strategies of the pre-Columbian Americas.     

Late Holocene Historical Ecology: The Timing of Vertebrate Extirpation on Crooked Island,Commonwealth of The Bahamas

We report eight new accelerator-mass spectrometer (AMS) radiocarbon (¹⁴C) dates performed directly on individual bones of extirpated species from Crooked Island, The Bahamas. Three dates from the hutia (Geocapromys ingrahami), recovered from a culturally derived bone assemblage in McKay's Bluff Cave (site CR-5), all broadly overlap from AD 1450 to 1620, which encompasses the time of first European contact with the Lucayan on Crooked Island (AD 1492). Marine fish and hutia dominate the bone assemblage at McKay's Bluff Cave, shedding light on vertebrate consumption by the Lucayans just before their demise. A fourth AMS ¹⁴C date on a hutia bone, from a non-cultural surface context in Crossbed Cave (site CR-25), is similar (AD 1465 to 1645) to those from McKay's Bluff Cave. From Pittstown Landing (site CR-14), an open coastal archaeological site, a femur of the Cuban crocodile (Crocodylus rhombifer) yielded an AMS ¹⁴C date of AD ～1050–1250, which is early in the Lucayan cultural sequence. From a humerus in a non-cultural surface context in 1702 Cave (site CR-26), we document survival of the Cuban crocodile on Crooked Island until AD ～1300–1400, which is several hundred years later than the well-documented extinction of Cuban crocodiles on Abaco in the northern Bahamas. We lack a clear explanation of why Cuban crocodiles likely survived longer on Crooked Island than on a larger Bahamian island such as Abaco. One AMS ¹⁴C date on Crooked Island's extinct, undescribed species of tortoise (Chelonoidis sp.) from 1702 Cave is BC 790 to 540 (2740 to 2490 cal BP), which is ～1500–1700 years prior to human arrival. A second AMS ¹⁴C date, on a fibula of this tortoise from McKay's Bluff Cave, is AD 1025 to 1165, thereby demonstrating survival of this extinct species into the period of human occupation.     

Chronologies in wood and resin: AMS C dating of pre-Hispanic Caribbean wood sculpture

This paper establishes a chronological framework for selected pieces of Caribbean (Taíno/Lucayan) wooden sculpture, enabling previously ahistoric artefacts to fit back into the wider corpus of pre-colonial material culture. Seventy-two ¹⁴C AMS determinations from 56 artefacts held in museum collections are reported, including 32 ceremonial duhos, or seats. Far from being constrained to the last few centuries prior to contact, the dates for these objects extend back to ca. AD 250, and include the artistic legacies of various cultures. Duhos in both low and high back styles are present from about AD 600, if not earlier, in a distribution that spans the Antillean island chain from Trinidad to Cuba. Complex, drug-related paraphernalia and elaborate ancestral reliquaries are in evidence by AD 1000, as are some distinctive regional styles – such as the unique iconography from the Bahamas and Turks and Caicos islands. This paper explores relevant methodological issues – from the challenges of working with museum pieces (e.g., uncertain provenance, discrete sampling techniques, impact of previous conservation treatments on dating results), to dealing with potential ‘in-built’ age in tropical hardwoods.     

Cultural and trade practices in Sincu Bara (Senegal): a multi-proxy investigation

The Sincu Bara site in Senegal is one of the most famous archeological sites in Western Africa. Here we present the results of a multi-proxy study that combined microscopic analyses, carbon content, stable carbon isotope (δ¹³C) and radiocarbon (¹⁴C) measurements. This investigation exhibits a chronological framework in two phases: from 400 yr AD to 650 yr AD and 650 yr AD to 900 yr AD. Furthermore, it shows that besides basic potteries, some potsherds are notable for a temper exclusively made with human-harvested C4 plants. Finally, the ¹⁴C analysis performed on the organic slip strongly indicates the use of bitumen or bitumen-derived products for red slip preparation. This suggests the establishment of trade relationships with Nigerian and/or Trans-Saharan populations as early as 400 yr AD.     

Isotopic investigation of pre-Hispanic macaw breeding in Northwest Mexico

The pre-Hispanic settlement of Paquimé (ca. 1200–1450 AD) lay outside of urban Mesoamerica in arid northern Chihuahua, Mexico, yet the excavated remains of 322 scarlet macaws, tropical parrots whose northernmost habitat is 500 km to the south, suggest that Paquimé had relationships with distant communities. Here, carbon and oxygen stable isotope analysis of 30 macaw bones determines whether the Paquimeños actively bred these parrots or traded with Mesoamerican groups to obtain the birds. The δ¹³C values indicate that the macaws ate a diet of C₄ plants, foods that were unavailable to wild macaws. In addition, δ¹⁸O data suggest that the majority of the macaws spent their entire lives at Paquimé. We conclude that the ancient Paquimeños were in fact breeding scarlet macaws, although one bone with δ¹⁸O values outside the local range suggests that the breeders also maintained exchange ties with the source areas of the birds. By confirming that Paquimeños implemented a system of local macaw reproduction outside the Mesoamerican region itself, this analysis provides new evidence about the economic and ideological interdependence of pre-Hispanic societies in the Americas. It is also suggestive of the pre-industrial capabilities of humans to extend the natural ranges of animal species.