Quantification and propagation of errors when converting vertebrate biomineral oxygen isotope data to temperature for palaeoclimate reconstruction

Oxygen isotope analysis of bioapatite in vertebrate remains (bones and teeth) is commonly used to address questions on palaeoclimate from the Eocene to the recent past. Researchers currently use a range of methods to calibrate their data, enabling the isotopic composition of precipitation and the air temperature to be estimated. In some situations the regression method used can significantly affect the resulting palaeoclimatic interpretations. Furthermore, to understand the uncertainties in the results, it is necessary to quantify the errors involved in calibration. Studies in which isotopic data are converted rarely address these points, and a better understanding of the calibration process is needed. This paper compares regression methods employed in recent publications to calibrate isotopic data for palaeoclimatic interpretation and determines that least-squares regression inverted to x=(y-b)/a is the most appropriate method to use for calibrating causal isotopic relationships. We also identify the main sources of error introduced at each conversion stage, and investigate ways to minimise this error. We demonstrate that larger sample sizes substantially reduce the uncertainties inherent within the calibration process: typical uncertainty in temperature inferred from a single sample is at least ±4°C, which multiple samples can reduce to ±1-2°C. Moreover, the gain even from one to four samples is greater than the gain from any further increases. We also show that when converting δ18Oprecipitation to temperature, use of annually averaged data can give significantly less uncertainty in inferred temperatures than use of monthly rainfall data. Equations and an online spreadsheet for the quantification of errors are provided for general use, and could be extended to contexts beyond the specific application of this paper.Palaeotemperature estimation from isotopic data can be highly informative for our understanding of past climates and their impact on humans and animals. However, for such estimates to be useful, there must be confidence in their accuracy, and this includes an assessment of calibration error. We give a series of recommendations for assessing uncertainty when making calibrations of δ18Obioapatite-δ18Oprecipitation-Temperature. Use of these guidelines will provide a more solid foundation for palaeoclimate inferences made from vertebrate isotopic data.We are grateful to the University of Cambridge (AJEP) and the Royal Society (RES) for financial support

Laser ablation strontium isotope analysis of human remains from Harlaa and Sofi, eastern Ethiopia, and the implications for Islamisation and mobility

This is the final version. Available on open access from Taylor & Francis via the DOI in this recordThe ancient city of Harlaa in eastern Ethiopia was occupied between the mid-6th and early 15th centuries AD and played a significant role as a trading centre with links internationally. Besides goods, these trade links also served in spreading cultural and religious ideas between continents, including Islamic traditions which became prevalent in Ethiopia during this time. Here, we present the first strontium isotope analysis of human remains from an Islamic site in Ethiopia. Results show that individuals buried following Islamic traditions include people born and raised both in Harlaa itself and also in rural communities from the surrounding hinterland, revealing a resident local Muslim community and potential co-existence of Muslim and non-Muslim individuals across economic sectors. The repeatability of results produced by laser ablation in human teeth sampled multiple times around the tooth cusp is also confirmed, although small differences between simultaneously-forming molar elements from a single individual were observeEuropean Union Horizon 202

Reflections on Gravettian firewood procurement near the Pavlov Hills, Czech Republic

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThis paper draws attention to firewood as a natural resource that was gathered, processed and consumed on a daily basis by Palaeolithic groups. Using Gravettian occupation of the Pavlovsk� Hills as a case study (dated to around 30,000 years BP), we investigate firewood availability using archaeological, palaeoenvironmental and ecological data, including making inferences from charcoal in Pavlovian hearths. The collated evidence suggests that while dead wood was likely readily available in woodland areas where humans had not recently foraged, longer term occupations - or repeated occupation of the same area by different groups - would have quickly exhausted naturally occurring supplies. Once depleted, the deadwood pool may have taken several generations (~40-120 years) to recover enough to provide fuel for another base camp occupation. Such exhaustion of deadwood supplies is well attested ethnographically. Thus, we argue that Pavlovian groups likely managed firewood supplies using methods similar to those used by recent hunter-gatherers: through planned geographic mobility and by deliberately killing trees years in advance of when wood was required, so leaving time for the wood to dry out. Such management of fuel resources was, we argue, critical to human expansion into these cold, hitherto marginal, ecologies of the Upper Palaeolithic.AJEP is grateful to The Leverhulme Trust that funded this research, which was undertaken as part of the project Seasonality, Mobility and Storage in Palaeolithic hunting societies (RPG-2013-318)

Chronology and function of a new circular mammoth bone structure from Kostenki 11

This is the author accepted manuscript. The final version is available from Cambridge University Press via the DOI in this record.We report on assemblages of charcoal, burnt bone and microlithic debitage retrieved by flotation from a new circular mammoth bone feature discovered at Kostenki 11-Ia, Russian Federation, the first time a mammoth bone circle has ever been systematically sampled in this way. New radiocarbon dates are used to provide the first coherent chronology for the site, revealing it as one of the oldest such features on the Russian Plain and confirming occupation of this region during Greenland Stadial 3 at the onset of the last glacial maximum. Implications for human activity within and around the mammoth bone feature are discussed.Leverhulme Trus

Mobility and season of death of the Arctic foxes killed by Gravettian hunters at Kraków Spadzista, Poland

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThe Late Gravettian site of Kraków Spadzista is important for understanding human behaviour and adaptation in cold, northern and marginal landscapes approaching the coldest part of the last glacial cycle. This paper focuses on the large assemblage of Arctic fox (Vulpes lagopus L.) remains found at the site, and presents new data on the mobility patterns and season of death of the animals killed by Gravettian hunters. Laser ablation strontium isotope analysis of teeth from five individuals indicates that each analysed fox was born and grew up in a different and isotopically distinct location, and had migrated tens or hundreds of kilometres into the vicinity of Kraków Spadzista before being killed by Gravettian hunters. Season of death data gathered from the dental cementum of at least 10 fox individuals demonstrate that the majority were killed in a window between late winter and late spring. Given the predictable nature of seasonal changes in Arctic fox hide quality and bodily fat reserves, we argue that the foxes were most likely killed at the start of this window, i.e. in late winter. The results are interesting for reconstructing the context to human hunting strategies in the Late Gravettian, revealing the choices made by hunters about where and when to procure these small prey.National Science Center, Polan

Material cosmopolitanism: the entrepot of Harlaa as an Islamic gateway to eastern Ethiopia

This is the author accepted manuscript. The final version is available from Cambridge University Press via the DOI in this record.The investigation of Islamic archaeology in Ethiopia has until recently been neglected. Excavations at Harlaa, a large urban centre in eastern Ethiopia, are now beginning to redress this lack of research attention. By establishing occupation and material sequences, and by assessing the chronology and material markers of Islamisation, recent work provides important new insight on the presence and role of Muslims and Islamic practice at Harlaa, and in the Horn of Africa more generally. The results challenge previous assumptions of cultural homogeneity, instead indicating the development of cosmopolitanism. They also suggest a possible historical identity for Harlaa: as Hubät/Hobat, the capital of the Hārlā sultanate.European Commissio

A Multi-Proxy Reconstruction of Environmental Change in the Vicinity of the North Bay Outlet of Pro-Glacial Lake Algonquin

We present a multi-proxy study of environmental conditions during and after the recessional phases of pro-glacial Lake Algonquin in the vicinity of the North Bay outlet, Great Lakes Basin. Data presented comes from a new sedimentary profile obtained from the Balsam Creek kettle lake c. 34 km north-east of the city of North Bay. This site lies close to the north-east margin of the maximum extent of the post-Algonquin lake sequence, which drained through the Ottawa-Mattawa valley system. Our data are presented against a Bayesian age-depth model, supporting and extending regional understanding of vegetation succession in this part of north-east Ontario. The core profile provides a minimum age for the formation of the glacial outwash delta in which the kettle is set, as well as tentative timing for the Payette (post-Algonquin) lake phase. We highlight two discrete intervals during the Early Holocene, with modelled mean ages of: 8475–8040 cal. BP (332–316 cm) and 7645 cal. BP (286 cm), when climatic aridity affected the growth of vegetation within the kettle vicinity. Association with volcanic activity is posited. Cryptotephra dating to 7660–7430 cal. BP (mean age: 7580 cal. BP) is chronologically and geochemically assigned to the Mazama climactic eruption, while an earlier ash accumulation 8710–7865 cal. BP is tentatively sourced to an unknown eruption also in the Cascades region of Oregon. Outside of these periods, the Balsam Creek sequence shows considerable habitat stability and a character akin to that seen at more southerly latitudes. On this evidence we propose that access to reliable resources within kettle features could have aided the initial colonisation of northern Ontario’s environmentally dynamic early post-glacial landscape

Proboscideans on parade: a review of the migratory behaviour of elephants, mammoths, and mastodons

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThe ecology and behaviour of woolly and Columbian mammoths and mastodons have been extensively studied. Despite this, their patterns of mobility, and particularly the question of whether or not they migrated habitually, remains unclear. This paper summarises the current state of knowledge regarding mobility in these species, reviewing comparative datasets from extant elephant populations as well as isotopic data measured directly on the ancient animals themselves. Seasonal migration is not common in modern elephants and varies between years. Nonetheless, non-migratory elephants can still have considerable home ranges, whose size is affected mainly by habitat, seasonal availability of water and food, and biological sex. Strontium isotope analyses of woolly mammoths, Columbian mammoths, and mastodons demonstrate plasticity in their migratory behaviour as well, probably in response to spatio-temporal variations in ecological conditions. However, biological sex is difficult to establish for most proboscidean fossils and its influence on the results of Sr analyses can therefore not be assessed. Advances in intra-tooth sampling and analytical methods for strontium isotope analysis have enabled research on intra-annual movement, revealing nomadic behaviour in all three species. Sulfur isotopes have been analysed from woolly mammoth remains numerous times, but its methodology is not yet developed well enough to inform on past proboscidean mobility in as much detail as strontium studies. The inter- and intra-individual variation in migratory behaviour in mammoths and mastodons implies that their role in the subsistence strategies of Palaeolithic people may have fluctuated as well. Further assessment of hominin-proboscidean predator-prey interactions will require a more detailed understanding of proboscidean habitual mobility in specific contexts and places. Strontium isotope studies based on multi-year enamel sequences from multiple individuals have the potential to provide this insight.Natural Environment Research Council (NERC

Seasonal records of palaeoenvironmental change and resource use from archaeological assemblages

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordSeasonal climate variability can affect the availability of food, water, shelter and raw materials. Therefore, robust assessments of relationships between environmental change and changes in human behaviour require an understanding of climate and environment at a seasonal scale. In recent years, many advances have been made in obtaining seasonally-resolved and seasonally-focused palaeoenvironmental data from proxy records. If these proxy records are obtained from archaeological sites, they offer a unique opportunity to reconstruct local climate variations that can be spatially and temporally related to human activity. Furthermore, the analysis of various floral and faunal remains within archaeological sites enables reconstruction of seasonal resource use and subsistence patterns. This paper provides an overview of the growing body of research on seasonal palaeoenvironmental records and resource use from archaeological contexts as well as providing an introduction to a special issue on the same topic. This special issue of Journal of Archaeological Science Reports brings together some of the latest research on generating seasonal-resolution and seasonally-focused palaeoenvironmental records from archaeological sites as a means to assessing human-environment interaction. The papers presented here include studies on archaeological mollusc shells, otoliths, bones and plant remains using geochemical proxies including stable isotopes (δ18O, δ13C, δ15N) and trace elements (Mg/Ca). The geographical scope encompasses parts of Europe, North America and the Levant, while temporally the studies range from Palaeolithic to historical times

Performance and automation of ancient DNA capture with RNA hyRAD probes

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordData Availability: The datasets generated for this study can be accessed in the ENA (Accession Number PRJEB43744). The program for piloting the Opentrons OT-2 robot can be accessed at https://github.com/TomaszSuchan/opentrons-hyRAD.DNA hybridization-capture techniques allow researchers to focus their sequencing efforts on pre-selected genomic regions. This feature is especially useful when analyzing ancient DNA (aDNA) extracts, which are often dominated by exogenous environmental sources. Here, we assessed, for the first time, the performance of hyRAD as an inexpensive and design-free alternative to commercial capture protocols to obtain authentic aDNA data from osseous remains. HyRAD relies on double enzymatic restriction of fresh DNA extracts to produce RNA probes that cover only a fraction of the genome and can serve as baits for capturing homologous fragments from aDNA libraries. We found that this approach could retrieve sequence data from horse remains coming from a range of preservation environments, including beyond radiocarbon range, yielding up to 146.5-fold on-target enrichment for aDNA extracts showing extremely low endogenous content (20-30%), while the fraction of endogenous reads mapping on- and off-target was relatively insensitive to the original endogenous DNA content. Procedures based on two, instead of a single round of capture, increased on-target coverage up to 3.6-fold. Additionally, we used methylation sensitive restriction enzymes to produce probes targeting hypomethylated regions, which improved data quality by reducing post-mortem DNA damage and mapping within multicopy regions. Finally, we developed a fully automated hyRAD protocol leveraging inexpensive robotic platforms to facilitate capture processing. Overall, our work establishes hyRAD as a cost-effective strategy to recover a set of shared orthologous variants across multiple ancient samples.University Paul Sabatier IDEX Chaire d’ExcellenceCNRSEuropean Union Horizon 2020Russian Foundation for Basic Researc