Testing Late Bronze Age mobility in southern Sweden in the light of a new multi-proxy strontium isotope baseline of Scania.

The Bronze Age of Sweden's southernmost region, Scania, is complex and intriguing. One could say that Scania represented in many ways a gateway for people, ideas and material culture connecting continental Europe with Sweden. Shedding light on the dynamics of human mobility in this region requires an in depth understanding of the local archaeological contexts across time. In this study, we present new archaeological human data from the Late Bronze Age Simris II site, located in an area of Scania showing a dynamic environment throughout the Late Bronze Age, thus likely involving various forms of mobility. Because the characterization of solid strontium isotope baselines is vital for delineating human mobility in prehistory using the strontium isotope methodology, we introduce the first environmentally based multi-proxy (surface water-, plant- and soil leachates) strontium isotope baselines for sub-regions of Scania. Our results show, that the highly complex and spatially scattered lithologies characterising Scania does not allow for a spatially meaningful, geology-based grouping of multi-proxy data that could be beneficial for provenance studies. Instead, we propose sub-regional baselines for areas that don't necessarily fully correspond and reflect the immediate distribution of bedrock lithologies. Rather than working with a Scania-wide multi-proxy baseline, which we define as 87Sr/86Sr = 0.7133 ± 0.0059 (n = 102, 2σ), we propose sub-regional, multi-proxy baselines as follows: Area 1, farthest to the north, by 87Sr/86Sr = 0.7184 ± 0.0061 (n = 16, 2σ); Area 2, comprising the mid and western part of Scania, with 87Sr/86Sr = 0.7140 ± 0.0043 (n = 48, 2σ); Area 3-4, roughly corresponding to a NW-SE trending zone dominated by horst-graben tectonics across Scania, plus the carbonate dominated south western part of Scania with 87Sr/86Sr = 0.7110 ± 0.0030 (n = 39, 2σ). Our results also reflect that the complexity of the geology of Scania requires systematic, high density, statistically sound sampling of multiple proxies to adequately constrain the baseline ranges, particularly of those areas dominated by Precambrian lithologies. The averaging effect of biosphere Sr in surface water might be beneficial for the characterization of baselines in such terranes. Our sub-regional, area-specific baselines allow for a first comparison of different baseline construction strategies (single-proxy versus multi-proxy; Scania-wide versus sub-regional). From the Late Bronze Age Simris II site, we identified six individuals that could be analysed for Sr isotopes, to allow for an interpretation of their provenance using the newly established, environmental strontium isotope baselines. All but one signature agrees with the local baselines, including the 87Sr/86Sr value we measured for a young individual buried in a house urn, typically interpreted as evidence for long distance contacts. The results are somewhat unexpected and provides new aspects into the complexity of Scandinavian Bronze Age societies.

Individual geographic mobility in a Viking-Age emporium-Burial practices and strontium isotope analyses of Ribe's earliest inhabitants.

Individual geographic mobility is a key social dynamic of early Viking-Age urbanization in Scandinavia. We present the first comprehensive geographic mobility study of Scandinavia's earliest emporium, Ribe, which emerged around AD 700 in the North Sea region of Denmark. This article presents the results of strontium isotope analyses of 21 individuals buried at Ribe, combined with an in-depth study of the varied cultural affinities reflected by the burial practices. In order to investigate geographic mobility in early life/childhood, we sampled multiple teeth and/or petrous bone of individuals, which yielded a total of 43 strontium isotope analyses. Most individuals yielded strontium isotope values that fell within a relatively narrow range, between 87Sr/86Sr = 0.709 to 0.711. Only two individuals yielded values >87Sr/86Sr = 0.711. This suggests that most of these individuals had local origins but some had cultural affinities beyond present-day Denmark. Our results raise new questions concerning our understanding of the social and cultural dynamics behind the urbanization of Scandinavia.

A strontium isotope baseline of Cyprus. Assessing the use of soil leachates, plants, groundwater and surface water as proxies for the local range of bioavailable strontium isotope composition.

In this study, a strontium isotope baseline for Cyprus is presented. The aim of the study was two-fold; first to provide an environmental multi-proxy-based baseline (water/plants/soil leachates) suitable for archaeological provenance and mobility studies, food source authentication, and forensic investigations; and second, to contribute to the debate around which proxy (or combination of proxies) might be most suitable to define bioavailable fractions of strontium in geologically complex areas also exposed to sea-spray and other Sr-bearing aerosols. Lowest bioavailable strontium isotope signatures range is found within terranes dominated by ophiolites, where 87Sr/86Sr ratios range from 0.7055 to 0.7081, however, results reveal a high degree of variability in bioavailable 87Sr/86Sr ratios, both spatially, along depth profiles and amongst the different proxies. A narrower range of bioavailable Sr isotope signatures is observed within the Circum Troodos Sedimentary Successions (C.T.S.S.), both in spatial distribution and between different proxies. Observed range is 87Sr/86Sr = 0.7079 to 0.7089 in areas dominated by pre-Quaternary C.T.S.S., and 87Sr/86Sr ratios = 0.7076 to 0.7086 in areas covered by Quaternary C.T.S.S., revealing the lithologies to be very homogenous with respect to bioavailable strontium ratios. Intra-site variations in three archaeological sites (multiple samples from each site from within a 500 m radius) within the pre-Quaternary and Quaternary C.T.S.S. are smaller than inter-site variations, suggesting that tracing studies inferred from baselines sampled within a limited spatial area could lead to erroneous conclusions regarding provenance. The study points to the necessity for conducting multi-proxy, spatially extensive sampling to adequately characterize complex geological areas, if these should serve as reliable reference areas in provenance studies.

Mapping human mobility during the third and second millennia BC in present-day Denmark.

We present results of the largest multidisciplinary human mobility investigation to date of skeletal remains from present-day Denmark encompassing the 3rd and 2nd millennia BC. Through a multi-analytical approach based on 88 individuals from 37 different archaeological localities in which we combine strontium isotope and radiocarbon analyses together with anthropological investigations, we explore whether there are significant changes in human mobility patterns during this period. Overall, our data suggest that mobility of people seems to have been continuous throughout the 3rd and 2nd millennia BC. However, our data also indicate a clear shift in mobility patterns from around 1600 BC onwards, with a larger variation in the geographical origin of the migrants, and potentially including more distant regions. This shift occurred during a transition period at the beginning of the Nordic Bronze Age at a time when society flourished, expanded and experienced an unprecedented economic growth, suggesting that these aspects were closely related.

A matter of months: High precision migration chronology of a Bronze Age female.

Establishing the age at which prehistoric individuals move away from their childhood residential location holds crucial information about the socio dynamics and mobility patterns in ancient societies. We present a novel combination of strontium isotope analyses performed on the over 3000 year old "Skrydstrup Woman" from Denmark, for whom we compiled a highly detailed month-scale model of her migration timeline. When combined with physical anthropological analyses this timeline can be related to the chronological age at which the residential location changed. We conducted a series of high-resolution strontium isotope analyses of hard and soft human tissues and combined these with anthropological investigations including CT-scanning and 3D visualizations. The Skrydstrup Woman lived during a pan-European period characterized by technical innovation and great social transformations stimulated by long-distance connections; consequently she represents an important part of both Danish and European prehistory. Our multidisciplinary study involves complementary biochemical, biomolecular and microscopy analyses of her scalp hair. Our results reveal that the Skrydstrup Woman was between 17-18 years old when she died, and that she moved from her place of origin -outside present day Denmark- to the Skrydstrup area in Denmark 47 to 42 months before she died. Hence, she was between 13 to 14 years old when she migrated to and resided in the area around Skrydstrup for the rest of her life. From an archaeological standpoint, this one-time and one-way movement of an elite female during the possible "age of marriageability" might suggest that she migrated with the aim of establishing an alliance between chiefdoms. Consequently, this detailed multidisciplinary investigation provides a novel tool to reconstruct high resolution chronology of individual mobility with the perspective of studying complex patterns of social and economic interaction in prehistory.

Tracing the dynamic life story of a Bronze Age Female.

Ancient human mobility at the individual level is conventionally studied by the diverse application of suitable techniques (e.g. aDNA, radiogenic strontium isotopes, as well as oxygen and lead isotopes) to either hard and/or soft tissues. However, the limited preservation of coexisting hard and soft human tissues hampers the possibilities of investigating high-resolution diachronic mobility periods in the life of a single individual. Here, we present the results of a multidisciplinary study of an exceptionally well preserved circa 3.400-year old Danish Bronze Age female find, known as the Egtved Girl. We applied biomolecular, biochemical and geochemical analyses to reconstruct her mobility and diet. We demonstrate that she originated from a place outside present day Denmark (the island of Bornholm excluded), and that she travelled back and forth over large distances during the final months of her life, while consuming a terrestrial diet with intervals of reduced protein intake. We also provide evidence that all her garments were made of non-locally produced wool. Our study advocates the huge potential of combining biomolecular and biogeochemical provenance tracer analyses to hard and soft tissues of a single ancient individual for the reconstruction of high-resolution human mobility.

Strontium isotope signals in cremated petrous portions as indicator for childhood origin.

Dental enamel is currently of high informative value in studies concerning childhood origin and human mobility because the strontium isotope ratio in human dental enamel is indicative of geographical origin. However, many prehistoric burials involve cremation and although strontium retains its original biological isotopic composition, even when exposed to very high temperatures, intact dental enamel is rarely preserved in cremated or burned human remains. When preserved, fragments of dental enamel may be difficult to recognize and identify. Finding a substitute material for strontium isotope analysis of burned human remains, reflecting childhood values, is hence of high priority. This is the first study comparing strontium isotope ratios from cremated and non-cremated petrous portions with enamel as indicator for childhood origin. We show how strontium isotope ratios in the otic capsule of the petrous portion of the inner ear are highly correlated with strontium isotope ratios in dental enamel from the same individual, whether inhumed or cremated. This implies that strontium isotope ratios in the petrous bone, which practically always survives cremation, are indicative of childhood origin for human skeletal remains. Hence, the petrous bone is ideal as a substitute material for strontium isotope analysis of burned human remains.