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The lay of land: Strontium isotope variability in the dietary catchment of the Late Iron Age proto-urban settlement of Basel-Gasfabrik, Switzerland
Abstract
Basel-Gasfabrik (Switzerland) comprises an extensive La Tène (chiefly Lt D, 150–80 BCE) settlement and two associated cemeteries at which strontium (87Sr/86Sr) isotope analysis of human and animal teeth investigated regional and supra-regional contacts. The interpretation of the analytic data, however, requires information on the isotopic baseline values around the site. Using 102 modern vegetation and 9 water samples from 51 localities, this study characterizes the isotopic ratios of the biologically available strontium of geological units and watercourses around Basel and compares these to 28 human infant, 6 pig, and 5 dog teeth from the site. Furthermore, pedological criteria evaluate the suitability of landforms for crop and pasturelands. The 87Sr/86Sr ratios of the environmental samples from geological units in up to 50 km distance varied between 0.70776 and 0.71794. Human infant teeth exhibited much more homogeneous 87Sr/86Sr ratios (0.70847–0.70950), which coincided largely with those of potential arable soils around Basel and indicate targeted exploitation of landscapes for agriculture. The more variable values of the faunal teeth suggest more widely ranging habitats or imports from the site's hinterlands. Two local isotope ranges were defined based on archaeological enamel samples and modern vegetation data from a confined radius around Basel. The study documents the complexity of distinguishing local and non-local individuals in a geologically heterogeneous region as well as the potential of isotope analyses to explore prehistoric land-use patterns.
... The two bones exhibited a ratio of 0.7090 and 0.7091 respectively, which is very similar to the isotope composition of the sampled deciduous teeth as well as the first and third molar of the female Figure 3). 57 iScience Article from grave 4 and to the third molar of the male from grave 9 (mean value: 0.7090 G 0.0001; see Table 1). These samples perfectly match the so-called local I baseline range (0.7083-0.7093) estimated by D. Brö nnimann, C. Knipper, and colleagues 57,58 (Figure 7). ...
... Nonetheless, these values still fit in the so-called local II Sr isotope baseline range (0.7093-0.7114). 57,58 The range is thought to correspond with the arable land in the surroundings of Basel-Gasfabrik -including the surroundings of Basel-Waisenhaus. However, this wide range resulting from the heterogeneous environmental settings in the area ( Figure 3) is not just specific for Basel but can be found in surrounding regions [66][67][68][69][70][71] and other areas across Europe. ...
... 59 The model was used to assess if the Sr isotope baseline suggested by Brö nnimann and colleagues for the Iron Age site Basel-Gasfabrik, located 1.8 km away to the north-west (Figure 3), could equally be used for this study. 57 We used various environmental parameters to identify suitable settlement spots based on geological and pedological attributes, groundwater level anomalies, landscape accessibility, and permeability, as well as the potential premodern hydrologic system in a 1.5 km distance around the site. This activity sphere was thought to predict a self-sufficient crop cultivation strategy best. ...
The Basel-Waisenhaus burial community (Switzerland) has been traditionally interpreted as immigrated Alamans because of the location and dating of the burial
ground – despite the typical late Roman funeral practices. To evaluate this hypothesis, multi-isotope and aDNA analyses were conducted on the eleven individuals buried there. The results show that the burial ground was occupied around AD 400 by people belonging largely to one family, whereas isotope and genetic recordsmost probably point toward a regionally organized and indigenous, instead of an immigrated, community. This strengthens the recently advanced assumption that the withdrawal of the Upper Germanic-Rhaetian limes after the ‘‘Crisis of the Third Century AD’’ was not necessarily related to a replacement of the local population by immigrated Alamannic peoples, suggesting a long-lasting continuity of occupation at the Roman periphery at the Upper and High Rhine region.
... However, the analyses require the determination of local isotope baselines, whose reliability is closely linked to the size, type, availability, and preservation of the baseline sample (Gerling, 2015;Makarewicz and Sealy, 2015). Because the bioavailable strontium composition depends mostly on the geological and pedological settings, soil samples and published 87 Sr/ 86 Sr ratios of the geological units are widely used to determine a local strontium isotope baseline (Brönnimann et al., 2018;Giblin, 2009;Heinrich-Tamáska and Schweissing, 2011;Knudson et al., 2014;Shaw et al., 2009;Whittle et al., 2013). However, other environmental parameters such as sea-spray-effect in coastal areas can impact the local strontium composition, rendering reliance on only geological data unreliable (Alonzi et al., 2020;Bentley, 2006;Makarewicz and Sealy, 2015;Montgomery, 2010;Naumann et al., 2014;Price et al., 2002;Wong et al., 2018). ...
... Because plants absorb the biologically available strontium and their strontium isotope composition is crucial for the isotope abundance within the human tissues, they could be considered a substantially more suitable sample category (Corti et al., 2013;Knipper, 2004;Wong et al., 2018). However, the samples should be taken in considerable distance from modern arable fields or in forested areas to avoid contamination by modern fertilizers (Alt et al., 2014;Brönnimann et al., 2018). ...
... Major advances in strontium isotope sampling strategies and baseline determination have been proposed by manifold authors (Bentley et al., 2004;Hoogewerff et al., 2019;Maurer et al., 2012). For example, Brönnimann et al. (2018) minimized the bias in the data by the integration of a large number and variety of samples, including mineral, botanical, faunal, and human samples from both an archaeological and modern context (Brönnimann et al., 2018). However, limited time availability, financial resources, or access to the data would not allow for fulfilling these requirements. ...
Strontium isotope analysis has recently proven to be a useful tool to elucidate population movements and
subsistence strategies in ecological and archaeological sciences. The interpretation depends on the size, type,
availability, and preservation of the sample and the reliability of the produced strontium isotope baseline.
However, collecting quantitatively and qualitatively suitable baseline samples is considered a challenging task in
archaeological research. To meet these challenges, we introduce an innovative analytical technique, which enables
the analysis of small sample sizes from heterogeneous site distribution and environmental settings. This
article integrates multivariate environmental modelling and bioarchaeological data of 49 sites to establish the
first scale-based differentiation between site-specific and micro-regional strontium isotope baselines with various
sample sizes in Hungary. In future mobility studies, this approach will allow distinguishing human and faunal
movement ranges on different geographical scales.
... Strontium isotope analyses ( 87 Sr/ 86 Sr ratios) are now well-established for assessing whether animals were raised locally or in other geological areas, as they provide direct evidence of geological origin during the period of enamel mineralisation (e.g. Balasse et al. 2002;Evans et al. 2007;Bendrey, Hayes, and Palmer 2009;Viner et al. 2010;Minniti et al. 2014;Brönnimann et al. 2018;Madgwick et al. 2019). In order to explore the degree of livestock mobility and the possible arrival of domestic animals from overseas, strontium isotopic analyses were performed on 57 caprine teeth (sheep and goats) from seven Bronze Age sites of different functionalities from Mallorca and Menorca. ...
... Previous comprehensive studies characterising biogenic strontium isotopic ratios (e.g. Evans et al. 2010;Brönnimann et al. 2018) suggest that present-day leaves from trees with deep roots located in undisturbed forests offer reliable data to characterise bioavailable strontium isotopic data. In the present study, however, the lack of undisturbed vegetation at the archaeological sites prevented us from collecting reliable leaf samples. ...
... Valenzuela- Oliver et al. 2016;Valenzuela-Lamas et al. 2018), as well as other comprehensive studies analysing Miocene, Triassic and Jurassic bedrocks from inland Europe (e.g. Brönnimann et al. 2018;Willmes et al. 2018;Bataille et al. 2020). All these works consistently indicate a range between 0.7080 and 0.7100 for the bedrocks present in Mallorca and Menorca. ...
This study presents the 87Sr/86Sr ratios from the tooth enamel of 57 sheep and goat specimens, in order to explore animal mobility in the Middle and Late Bronze Age society of the Balearic Islands (Naviform period). Seven archaeological sites from Mallorca and Menorca located in different biotopes and with different functionalities were selected. The results provide some of the first data on the geographic range of meat provisioning at each site. In addition, several present-day leaves, as well as tooth dentine and bones were analysed to assess local strontium isotopic ratios in different geological layers existing in the Balearic Islands. The results suggest that most caprines were sourced from the neighbouring areas of each site, but also suggest a correlation between strontium isotope variability and site function: domestic settlements and sites related with maritime exchanges had significantly more variability compared to fortified sites. In addition, the ritual cave of Cova del Camp del Bisbe had the highest diversity of strontium isotopic ratios, thus suggesting that caprines were brought here from a variety of different locations.
... Human dental enamel sampled of strontium and oxygen isotope analyses and related results. individual was probably mobile or changed its dietary habits during its life (Bentley, 2006;Brönnimann et al., 2018;Maurer et al., 2012). Baseline samples originated directly from the sites and were not collected from the surroundings. ...
... It illustrates that at ALE, BAL, BAM and MORT, human bone samples show slightly higher 87 Sr/ 86 Sr ratios compared to shell and faunal dental enamel samples. The human bone samples, which are influenced by the filling material of the grave-pit, are not necessarily representative for the bioavailable strontium of a whole catchment area (Brönnimann et al., 2018;Kempf, in preparation). The faunal samples mostly correspond to Sus domesticus, which might have been kept within a small-scale spatial distance around the Neolithic sites or in the wetlands of the river Sárvíz -at least in the case of ALE. ...
... The faunal samples mostly correspond to Sus domesticus, which might have been kept within a small-scale spatial distance around the Neolithic sites or in the wetlands of the river Sárvíz -at least in the case of ALE. The human bone and faunal tooth enamel samples are therefore assumed to provide complementary data regarding strontium isotope baselines (Bentley, 2006;Brönnimann et al., 2018;Depaermentier, in preparation;Slovak and Paytan, 2011). When considered separately, BAL shows a very different site-specific baseline compared to BAM (see Fig. 3E). ...
A variety of interdisciplinary research on mobility and migration patterns in Neolithic Hungary has recently contributed to the explanatory models of the Neolithisation across Europe. Most of these models were based on a combination of the spatial distribution of material culture or bioarchaeological and genetic analyses to determine large-scale migration and social or population-dynamic development. This paper aims at contributing to the current discussion by introducing a comprehensive and interdisciplinary multivariate environmental and multiproxy strontium and oxygen isotope analyses in combination with detailed archaeological interpretation of unique Neolithic site-complexes in southern Transdanubia. The integration of historical and modern environmental attributes, bioarchaeological data, and material typology allows for the determination of small-and large-scale mobility patterns and subsistence strategies in southern Hungary.
... All in all, the rare combination of an extensive, well investigated settlement with large numbers of diverse archaeological finds and Table 2 (Background map: Geology of Switzerland 1:500,000; Bundesamt für Landestopographie swisstopo. Data after: Brönnimann et al., 2018, Kloppmann, 2003Kloppmann et al., 2013). associated human skeletal remains from various contexts offers ideal conditions for in-depth integrative analyses. ...
... D). Their strontium isotope composition and implications for baseline variations in the wider surroundings of the site are discussed in a separate publication (Brönnimann et al., 2018). The comparative samples represent the major geological units in an area from the Kaiserstuhl hills in the north to the Swiss Jura in the south and from the Vosges in the west to the Black Forest in the East. ...
... Such terraces and alluvial sediments accompany the water course on both sides. To the northeast of the Basel-Gasfabrik site, the low mountain Fig. 3. Estimation of local strontium isotope baselines at Basel-Gasfabrik using human infants' deciduous teeth and permanent first molars (range I), Iron Age pig and dog teeth from the site (range II) as well as modern water (this study /Brönnimann et al., 2018, Kloppmann, 2003, Kloppmann et al., 2013, modern vegetation (Brönnimann et al., 2018), and Neolithic human enamel samples from Mulhouse-Est and Ensisheim from Bickle et al. (2013). The classification of the sampling locations of modern vegetation based on Brönnimann et al. (2018). ...
The Basel-Gasfabrik site (Switzerland) is among the largest and best investigated proto-urban centres of the La Tène period (chiefly La Tène C2/D1; 200/150–80 BCE). Excavations revealed evidence of an urban lifestyle, crafts production as well as a multitude of imported goods. Human skeletal remains were recovered both from two cemeteries and from various settlement features. Strontium (87Sr/86Sr) and oxygen (δ18Op) isotope analyses aimed at an assessment of the role of residential changes in the makeup of the site's population, the positioning of Basel-Gasfabrik in local, regional, and long-distance networks, and the exploration of possible correlations between the complex mortuary practices and the individuals' residential history. The study involved 94 enamel samples from 54 human individuals, while archaeological animal teeth and modern vegetation and water samples provided baseline information. The 87Sr/86Sr and the δ18Op ratios of the human teeth varied widely between 0.70755 and 0.71655 and 14.7 and 19.3 ‰, respectively, with more variation among adult males and females than among juveniles. Both the archaeological setting and the isotope data attest to lively contacts of the central site to its hinterland, but also to distant regions, such as the Mediterranean. Differences in the isotope data of successively formed tooth crowns of some of the adult population point to residential changes in childhood. Possible explanations include fosterage as an important element in strengthening regional and interregional ties among Iron Age communities, settlement centralization, and mobile animal husbandry practices. However, areas of origin or patterns of mobility were not among the key factors which shaped the complex mortuary practices.
... These enhanced inter-site and intra-site variations clearly reflects the heterogeneous geological background, which demand a denser sampling of multi-proxy archives to better constrain a statistically defined baseline range in these terranes. The larger variations of bioavailable strontium isotopic ratios in areas characterized by older crystalline rocks, compared to areas dominated by sedimentary carbonates, have been previously observed and reported in baseline studies (Britton et al., 2020;Brönnimann et al., 2018;Evans et al., 2010;Frank et al., 2021a,b;Frei & Frei, 2013;Hodell et al., 2004;Snoeck et al., 2020;Willmes et al., 2018). Such increased compositional variations do also occur in areas dominated by ophiolites as shown in the study by Ladegaard-Pedersen et al. (2020). ...
... The baseline constraints are often given by two standard deviation bands around a mean value (Alt et al., 2014;Brönnimann et al., 2018;Frei & Frei, 2011;Hodell et al., 2004;Ladegaard-Pedersen et al., 2020). Given that the distribution of proxy data is normal, the calculated baseline range will include c. 95% of the data. ...
The evidence of prehistoric long-distance exchange networks in northern Italy is overwhelming, attested by several finds of non-local raw materials in Bronze Age pile-dwelling settlements of Lake Garda and eastern Po plain, like amber beads and bronze artefacts. Metals are dispersed throughout Bronze Age Europe from mining communities within the Alpine regions, and possibly local artefacts, like the Peschiera-type daggers, are known from archaeological records throughout Europe. This positions the region as part of organized networks of trade and communication connecting prehistoric Europe from north to south. This, however, does not in itself indicate a similar long-distance mobility of prehistoric individuals. To investigate individual, human provenance and mobility, the strontium (Sr) isotope methodology compares strontium isotope analysis of human remains to bioavailable strontium isotope baselines characterizing the regions of interest. We present here environmentally based, multi-proxy (water, soil leachates and plants) Sr baselines from the Lake Garda region. Our results show two separate baselines, roughly corresponding to the geographical distribution of rock types and erosional products thereof. One baseline is valid for the Lake Garda region, where Mesozoic carbonates are a dominant surface-near strontium source, and for the central Po plain north of River Po. We constrain this to ⁸⁷Sr/⁸⁶Sr = 0.7088 ± 0.0014 (2σ; n = 44) when including 9 compatible samples reported previously. The second Sr-baseline is valid for Alpine areas dominated by magmatic (basalts excluded) and metamorphic bedrock around the Fersina valley. We constrain this to ⁸⁷Sr/⁸⁶Sr = 0.7146 ± 0.0058 (2σ; n = 22) when including 11 compatible samples reported in previous studies. The baselines are compatible with previously reported results of other Sr proxies such as snails, archaeological fauna, and agricultural soils and products from the region.
... The classification of 87 Sr/ 86 Sr ratios as non-local requires comparative data that characterize the isotope ratios of the biologically available strontium. Samples to establish Sr isotope baselines can include enamel of supposedly locally fed animals from archaeological contexts, modern water or vegetation as well as archaeological bones [43][44][45][46][47]. ...
... Combined evidence of the isotope, archaeological, and anthropological data identified twelve individuals of supposedly shared origin and cultural tradition [graves 29,34,43,46,51,69,72,73,74,77,80,82]. They had radiogenic strontium isotope ratios above the local range (c. ...
The decline of the Roman rule caused significant political instability and led to the emergence of various ‘Barbarian’ powers. While the names of the involved groups appeared in written sources, it is largely unknown how these changes affected the daily lives of the people during the 5th century AD. Did late Roman traditions persist, did new customs emerge, and did both amalgamate into new cultural expressions? A prime area to investigate these population and settlement historical changes is the Carpathian Basin (Hungary). Particularly, we studied archaeological and anthropological evidence, as well as radiogenic and stable isotope ratios of strontium, carbon, and nitrogen of human remains from 96 graves at the cemetery of Mözs-Icsei dűlő. Integrated data analysis suggests that most members of the founder generation at the site exhibited burial practises of late Antique traditions, even though they were heterogeneous regarding their places of origin and dietary habits. Furthermore, the isotope data disclosed a nonlocal group of people with similar dietary habits. According to the archaeological evidence, they joined the community a few decades after the founder generation and followed mainly foreign traditions with artificial skull modification as their most prominent characteristic. Moreover, individuals with modified skulls and late Antique grave attributes attest to deliberate cultural amalgamation, whereas burials of largely different isotope ratios underline the recipient habitus of the community. The integration of archaeological and bioarchaeological information at the individual level discloses the complex coalescence of people and traditions during the 5th century.
... The Sr isotopic ratio ( 87 Sr/ 86 Sr) varies in different geological formations according to the age and original rubidium (Rb) /strontium (Sr) ratio of the bedrock, leading to high radiogenic 87 Sr/ 86 Sr ratios in old or crustal rocks, and low 87 Sr/ 86 Sr ratios in young or mantle rocks [23,36]. The 87 Sr/ 86 Sr isotope composition of plants reflects the strontium isotopic ratios of the underlying bedrock, as biologic processes involved during plant growth do not entail isotopic fractionation of strontium isotopes [37][38]. Other factors affecting strontium ratios in plants include a significant contribution of rainfall water [39] atmospheric pollution and the use of modern fertilizers [40][41][42][43][44]. ...
... The porosity of bones makes their strontium signature susceptible to diagenetic alteration, but the isotopic signature of tooth enamel bioapatite reflects the period of tooth formation with little subsequent change [47][48]. Therefore, strontium isotope ratios from tooth enamel indicate the type of geological formation from which food and water were sourced during the period of mineralization of the tooth analysed [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]49]. ...
Animal mobility is a common strategy to overcome scarcity of food and the related over-grazing of pastures. It is also essential to reduce the inbreeding rate of animal populations, which is known to have a negative impact on fertility and productivity. The present paper shows the geographic range of sheep provisioning in different phases of occupation at the Iron Age site of Turó de la Font de la Canya (7th to 3rd centuries BC). Strontium isotope ratios from 34 archaeological sheep and goat enamel, two archaeological bones and 14 modern tree leaves are presented. The isotopic results suggest that sheep and goats consumed at the site were reared locally (within a few kilometres radius) during the whole period of occupation. The paper discusses the isotopic results in light of the socio-political structure of this period, as complex, strongly territorial societies developed during the Iron Age in the north-east Iberian Peninsula.
... Lacking vegetation or soil samples from the analyzed area we estimated the local strontium isotopic range based on three archaeological pig teeth from Cornaux. Pigs, as well as micromammals and terrestrial snails, are often used in provenience studies as a proxy of the local isotopic values due to the fact that they are often kept and fed locally 100,101 . The diet of domestic pigs is indeed similar to that of humans 102 , including typically remnants of human activities like decomposing vegetables, food leftovers and waste from both humans and animals 100 . ...
Cornaux/Les Sauges (Switzerland, Late Iron Age) revealed remnants of a wooden bridge, artifacts, and human and animal skeletal remains. The relationship between the collapsed structure and the skeletal material, whether it indicates a potential accident or cultural practices, remains elusive. We evaluate the most plausible scenario for Cornaux based on osteological, taphonomic, isotopic, and paleogenomic analysis of the recovered individuals. The latter amount to at least 20 individuals, mostly adult males. Perimortem lesions include only blunt force traumas. Radiocarbon data fall between the 3rd and 1st c. BCE, although in some cases predating available dendrochronological estimates from the bridge. Isotopic data highlight five to eight nonlocals. No close genetic relatedness links the analyzed skeletons. Paleogenomic results, the first for Iron Age Switzerland, point to a genetic affinity with other Central and Western European Iron Age groups. The type of skeletal lesions supports an accidental event as the more plausible explanation. Radiocarbon data and the demographic structure of the sample may suggest a sequence of different events possibly including executions and/or sacrifices. Isotopic and paleogenomic data, while not favoring one scenario over the other, do support earlier interpretations of the last centuries BCE in Europe as a dynamic period from a biocultural perspective.
... Previous comprehensive studies characterizing biogenic strontium isotopic ratios (e.g. Evans et al. 2010, Brönnimann et al. 2018, Willmes et al. 2018 suggest that present-day leaves from trees with deep roots located in undisturbed forests offer reliable data to characterise bioavailable strontium isotopic data. As the archaeological site of Can Roqueta is surrounded by motorways and industrial buildings, we used three dentine samples in addition to two present-day oak leaves in order to assess the strontium isotopic variability at the site (Fig. 3). ...
Equids played an important role in the development of communication in past societies, and were part of the
exchanges between populations. The multi-isotopic study (strontium, carbon and oxygen isotopes) conducted on
equid teeth from Bronze and Early Iron Age Can Roqueta suggests that animals originate from diverse locations
and their diet was carefully managed. The enriched oxygen and carbon isotopic ratios in equid teeth compared
with other taxa from the same site suggest that equids may have drunk from water troughs, thus creating a 13C
and 18O isotopic enrichment and partial covariance, similar to a “lake” effect. This is the most comprehensive
study on equid mobility in Iberia so far.
... A number of studies draw inferences directly from human data using the distribution of human enamel data to determine the local range of 87 Sr/ 86 Sr (e.g. [69][70][71][72][73]). The main peak of the distribution of the data can be interpreted as the local 87 Sr/ 86 Sr ratio for humans [74], provided by some temporal depth of the data and the absence of evidence that most of the population was non-local (e.g., [75]). ...
During the transition from Late Antiquity to the Middle Ages, the Roman Empire dissolved in the West and medieval empires were founded. There has been much discussion about the role that migration played in this transition. This is especially true for the formation of the Baiuvariian tribe and the founding of this tribal dukedom, which took place from the 5th to the 6th century in what is now Southern Bavaria (Germany). In this study, we aimed to determine the extent of immigration during the beginning of this transformation and to shed further light on its character. To achieve this goal, we analyzed stable isotope values of strontium, carbon, and nitrogen from the teeth and bones of over 150 human remains from Southern Germany, dating from around 500 AD. This group of individuals included women with cranial modifications (ACD) which can be found sporadically in the burial grounds of this period. Our results showed an above-average migration rate for both men and women in the second half of the 5th century. They also indicate that a foreign background may also be assumed for the women with ACD. The demonstrably different origins of the immigrants from isotopically diverse regions, and the identification of local differences in detectable migration rate, as well as indication for different timing of residential changes, highlight the complexity of immigration processes and the need for more studies at the regional level.
... This consequently has a contaminant effect on Sr in the respective soils, potentially rendering these an inappropriate biosphere proxy archive for baselines in such areas/regions. Besides soil, plants and fauna, surface water is one of the proxies used to characterize the average bioavailable Sr isotope baselines of areas/regions (Brennan et al., 2014;Brönnimann et al., 2018;Frank et al., 2021b;Frei and Frei, 2011;Frei and Frei, 2013;Ladegaard-Pedersen et al., 2020;Ladegaard-Pedersen et al., 2021;Pacheco-Forés et al., 2020;Wang et al., 2018). While surface waters from larger water bodies might have the advantage to average out the bioavailable Sr of areas characterized by a complex bedrock geology and covered with glaciogenic sediments, like it is the case in southern Sweden (Ladegaard-Pedersen et al., 2021), recent studies questioned the significance of such surface waters as a reliable baseline proxy in Denmark (Thomsen and Andreasen, 2019). ...
Strontium (Sr) isotope based provenance and mobility studies of ancient humans and animals necessitate representative isoscapes/baselines. However, regions/terranes that were shaped and affected by glaciers during the last Ice Ages and are covered by glaciogenic sediments present a challenge with regards to the choice of suitable surface proxy archives. Recent studies proposed that only ⁸⁷Sr/⁸⁶Sr signatures from pristine areas are relevant for this purpose.
To test this theory, 160 new Sr concentrations [Sr] and ⁸⁷Sr/⁸⁶Sr signatures composed from ~960 subsamples of soil leachates and plants, complemented with 55 surface waters from agriculturally unaffected pristine forest sites from all over Denmark (island of Bornholm excluded) were analyzed. The results reveal that average ⁸⁷Sr/⁸⁶Sr signatures of all three proxies (plants: 0.7115 ± 0.0025; 2σ, n = 162; soil leachates: 0.7118 ± 0.0037; 2σ; n = 161, surface waters: 0.7104 ± 0.0030; 2σ, n = 55) are elevated compared to larger water bodies (creeks, rivers, lakes). In mixing diagrams, the data converge in a shared high [Sr] low ⁸⁷Sr/⁸⁶Sr endmember, which points to either remnant natural carbonates and/or organic components retaining carbonate Sr in the studied Podzols/Luvisols. The indications for more abundant carbonates in the past, compared to today's acid leached soils, implies that ⁸⁷Sr/⁸⁶Sr values measured from pristine forest locations and heathlands do not adequately reflect the biosphere compositions that prevailed ~12,000–2000 thousand years ago. Consequently, pristine forests in Denmark seem to be unsuitable proxy archive environments for constructing Sr isotope baselines for determining the provenance and mobility of ancient humans and animals. Hence, ⁸⁷Sr/⁸⁶Sr values measured in these pristine areas are non-representative and inadequate, and their use will lead to wrong interpretations.
Finally, our study sheds light on the complexity of defining relevant and representative isoscapes/baselines in significantly changing environments and areas where the surface biosphere conditions do not necessary reflect the underlying geology.
... A difference between the 87 Sr/ 86 Sr ratio of the dental enamel and burial place is interpreted as evidence of a change of residence or at least a change in the source of food during an individual's life. Such conclusions require a reliable determination of the biologically available strontium in the local (or regional) habitat of the individuals [45,48,49]. In this study, strontium isotope analysis followed methods previously described by C. Knipper and colleagues [50,51]. ...
The complexity of Neolithic population movements and their interpretation through material culture have been the subject of archaeological research for decades. One of the dominant narratives proposes that groups from the Starčevo-Körös-Criş complex spread from the central towards the northern Balkans in the Early Neolithic and eventually brought the Neolithic lifestyle into present-day Hungary. Broad geographical migrations were considered to shape the continuous expansion of Neolithic groups and individuals. However, recent archaeological research, aDNA, and isotope analyses challenged the synchronous appearance of specific material culture distributions and human movement dynamics through emphasizing communication networks and socio-cultural transformation processes. This paper seeks to retrace the complexity of Neolithic mobility patterns across Hungary by means of strontium and oxygen stable isotope analyses, which were performed on a total of 718 human dental enamel samples from 55 Neolithic sites spanning the period from the Starčevo to the Balaton-Lasinja culture in Transdanubia and from the Körös to the Tiszapolgár cultural groups on the Great Hungarian Plain (Alföld). This study presents the largest strontium and oxygen isotope sample size for the Neolithic Carpathian Basin and discusses human mobility patterns on various geographical scales and throughout archaeological cultures, chronological periods, and sex and gender categories in a multiproxy analysis. Based on our results, we discuss the main stages of the Neolithisation processes and particularly trace individual movement behaviour such as exogamy patterns within extensive social networks. Furthermore, this paper presents an innovative differentiation between mobility patterns on small, micro-regional, and supra-regional scales, which provides new insights into the complex organisation of Neolithic communities.
... Indeed, the 87 Sr/ 86 Sr values of modern plants are quite often used in archaeological mobility studies to define the isotopic signature of the local area (e.g. Brönnimann et al. 2018;Willmes et al. 2014). ...
In this paper, we examine the exchange of crops and livestock through the application of
strontium (87Sr/86Sr) isotope analysis on cereal grains and faunal tooth enamel from the
regional center of Uppåkra and three nearby settlements in Scania, southern Sweden, dating
to the first millennium AD. Around a third of the fauna have non-local 87Sr/86Sr values,
indicating the import of livestock from several different regions. After cleaning, almost all of
the cereal grains have non-local 87Sr/86Sr values, which is surprising given the nearby
abundance of fertile agricultural soils. We therefore suggest considering non-locally grown
crops to be those whose 87Sr/86Sr values fall outside the normal distribution; if this
approach is used, around 20% of the analyzed crop samples are interpreted as having
grown non-locally. This study demonstrates the potential of combining strontium isotopic
data of archaeobotanical and zooarchaeologica
... Baselines have previously been produced for e.g. the British Isles [28,29], France [30], Denmark [31][32][33], the Netherlands [34], Switzerland [35], parts of the North Atlantic regions [36] and in parts of Mesoamerica [37]. ...
The inland area of southwestern Sweden is well known for its well-preserved archaeological animal and human remains dating back to the Mesolithic and Neolithic (10000–4000 and 4000–1700 BC). They allow application of multiple bioarchaeological methods, giving insights into various and complementary aspects of prehistoric human life, as well as economic and social structures. One important aspect concerns human mobility and its relation to social networks and to circulation of objects. Here, strontium isotope analysis plays a crucial role. The present study aims to construct a strontium isotope baseline of southwestern Sweden with considerably greater coverage and higher resolution than previously published data. As the region has been affected by glacial events, the relation between bedrock geology and isotope signals of the bioavailable strontium in such areas is given special attention. We determined strontium isotope ratios for 61 water and five archaeological animal samples, and combined the data with previous measurements of two water and 21 non-domestic faunal samples. The results reveal a complex pattern. Several areas with distinct baseline ranges can be distinguished, although with overlaps between some of them. Overall, the bioavailable strontium isotope signals mirror the basement geology of the region. The highest ratios occur in the geologically oldest eastern parts of the Precambrian terrain, while lower ratios are found in the western part, and the lowest ratios occur in the youngest Paleozoic areas. At the same time, there are minor deviations compared to the underlying bedrock, due to glacial transport, overlying sediments, and local intrusions of younger rocks. The background data set now available allows for more nuanced and detailed interpretations of human and animal mobility in the region, in particular by identification of subregions with differing strontium isotope ratios within the Precambrian province. Also, we can now identify long distance mobility with greater confidence.
This paper presents the most extensive 87Sr/86Sr datasets from Late Prehistory contexts in addition to bioavailable 87Sr/86Sr values for baseline characterization on the Balearic Islands. A total of 149 caprine dental enamel samples from Mallorca, Menorca, and Formentera islands (Spain), and 35 environmental baseline samples covering the main geologies of these islands are presented here. In addition, a combination of strontium and oxygen sequential analysis was performed on seven individuals from two sites that showed some of the most diverse 87Sr/86Sr values to better understand their mobility patterns. The main goal of this research is to provide more information about isotopic variability of bioavailable strontium on the Balearic Islands and livestock management during the Bronze and Iron Ages, thus allowing us to understand how human communities exploited their landscape and interacted with other populations.
The Basel-Waisenhaus burial community (Switzerland) has been traditionally interpreted as immigrated Alamans due to the location and dating of the burial ground – despite the typical late Roman funeral practices. To evaluate this hypothesis, multi-isotope and aDNA analyses were conducted on the eleven individuals buried there. The results show that the burial ground was occupied around 400 AD by people belonging largely to one family, while isotope and genetic records most probably point towards a regionally-organized and indigenous, instead of an immigrated, community. This strengthens the recently advanced assumption that the withdrawal of the Upper Germanic-Rhaetian limes after the “Crisis of the Third Century AD” was not necessarily related to a replacement of the local population by immigrated Alamannic peoples, suggesting a long-lasting continuity of occupation at the Roman periphery at the Upper and High Rhine region.
Point pattern analysis (PPA) has gained momentum in archaeological research that models large-scale distributions of sites and explanatory covariates. As such, there has been increased interest in the bias of archaeological distributions, which mostly have an impact due to modern land-use change. These interactions, however, have not yet been fully explored. In order to better understand archaeological point patterns as functions of explanatory covariates, we offer three different approaches: (i) environmental preference modelling of archaeological records in different chronological phases; (ii) a custom bias surface that represents the variability of the regional landscape; (iii) an R-package (rbias) allowing the generation of a fuzzified bias surface based on Open Street Map (OSM) data.
Der Tätigkeitsbericht des Kantonsarchäologen bietet einen Überblick über die wichtigsten Kennzahlen und die Arbeiten in den verschiedenen Abteilungen der Archäologischen Bodenforschung im Jahr 2018.
Urbanization is one of the most important settlement shifts in human history and has been the focus of research within bioarchaeology for decades. However, there have been limited attempts to synthesize the results of these studies in order to gain a broader perspective on whether or how urbanization affects the biology, demography, and behavior of humans, and how these potential effects are embodied in the human skeleton. This paper outlines how bioarchaeology is well‐suited to examine urbanization in the past, and we provide an overview and examples of three main ways in which urbanization is studied in bioarchaeological research: comparison of (often contemporaneous) urban and rural sites, synchronic studies of the variation that exists within and between urban sites, and investigations of changes that occur within urban sites over time. Studies of urbanization, both within bioarchaeology and in other fields of study, face a number of limitations, including a lack of a consensus regarding what urban and urbanization mean, the assumed dichotomous nature of urban versus rural settlements, the supposition that urbanization is universally bad for people, and the assumption (at least in practice) of homogeneity within urban and rural populations. Bioarchaeologists can address these limitations by utilizing a wide array of data and methods, and the studies described here collectively demonstrate the complex, nuanced, and highly variable effects of urbanization.
Strontium isotope ratio (⁸⁷Sr/⁸⁶Sr) has been widely used to trace human migrations across geologically distinct landscapes in archaeological, ecological, food and forensic sciences. ⁸⁷Sr/⁸⁶Sr-based provenance studies require a detailed strontium reference map to make valid interpretations of mobility patterns for a given region. In this study, we first review the previous development for ⁸⁷Sr/⁸⁶Sr isoscapes relevant to research on migration and then present the first map of bioavailable ⁸⁷Sr/⁸⁶Sr values for China, based on 1935 measurements on biosphere samples collated from published research and supplemented by our targeted collection strategy. The results show that ⁸⁷Sr/⁸⁶Sr ratios in China span a large range and exhibit regional patterns largely dependent on the divergent geological conditions of each of China's tectonic blocks. We further combined river water ⁸⁷Sr/⁸⁶Sr values with lithology, integrated elemental data, and chemical weathering rates, to determine which dominant weathering patterns (e.g. silicate, carbonate or evaporite) have the most significant influence on ⁸⁷Sr/⁸⁶Sr ratios. The low ranges of ⁸⁷Sr/⁸⁶Sr ratios (< 0.711) are predominately present in the Xing'an-Mongolian orogenic belt, which is composed of mafic-ultramafic silicate rocks, as well as in the Yangtze Block and the Junggar terrane-Tian Shan-Tarim Block, which are both influenced by the weathering of carbonate rocks. The intermediate ranges of Sr isotopes (0.711–0.7125) are mainly found in the North China Block, the northern Tibetan Plateau, and the southern Tarim Block, which may be because of evaporite dissolution and silicate/carbonate weathering processes. The high ranges of Sr isotope ratio (> 0.7125) appear in the Cathaysia Block as well as some orogenic belts and the southeastern margin of the Tibetan Plateau, likely due to the influence of the metamorphic rocks and granitoid sources. Additionally, topography, differential weathering among lithologies, and eolian deposits (e.g. loess) are also significant factors that influence ⁸⁷Sr/⁸⁶Sr ratios in China. Our study reveals that the large variation of ⁸⁷Sr/⁸⁶Sr ratios across China is predominately driven by geological conditions, revealing that future Sr isotope provenance studies can shed on ancient and historical migrations in China.
Aus der Schweiz liegen erst wenige archäobotanisch bearbeitete eisenzeitliche Fundstellen vor. Unter ihnen kann die spätlatènezeitliche Siedlung Basel-Gasfabrik zu recht als die bislang am dichtesten beprobte und somit als die am besten untersuchte Fundstelle gelten. Im Rahmen der Dissertation von Peter Jud bestand erstmals die Möglichkeit, einen Teil der entnommenen Proben auszuwerten und Ernährung, Landwirtschaft und Umwelt der spätlatènezeitlichen Siedlung Basel-Gasfabrik zu beleuchten.
Die Inhalte von 12 spätlatènezeitlichen Gruben aus der Fundstelle Basel-Gasfabrik wurden mikromorphologisch untersucht, um Hinweise zur Genese und Taphonomie der Sedimente zu erhalten.
This paper presents the strontium (Sr) isotope composition of the teeth of Neolithic individuals from the Linearbandkeramik (LBK) pit-enclosure of Herxheim (South Palatinate, Germany). The Sr isotope analyses are vital for the comprehension of the extraordinary site of Herxheim with the abundant human bone modifications found there. The large number of dead individuals, as well as the various exotic styles of high quality pottery of the latest LBK phase, found with the fragmented human skeletons, support movement from foreign places to Herxheim. Sr isotopes of tooth enamel have been analyzed to establish the possible origins of the individuals at Herxheim. Initial results for individuals found in the regular Bandkeramik burial position and for samples from a concentration of fragmented skeletons indicate the presence of a significant amount of nonlocal individuals, in a proportion higher than reported for other LBK settlements to date. None of the modified skeletal remains from the site investigated thus far belong to indigenous individuals. The observed Sr isotope ratios often indicate basement rock signatures. A subgroup of individuals has high ⁸⁷ Sr/ ⁸⁶ Sr ratios of 0.712-0.715, suggesting similarities to a group of five juveniles found in the Neolithic settlement of Nieder-Mörlen/Hesse.
The late Iron Age (150–80 BC) proto-urban site of Basel-Gasfabrik, Switzerland, yielded numerous human skeletal remains, with individuals of all ages and both sexes being found in two cemeteries and in various features of the settlement itself. About 200 inhumations and two cremation burials as well as isolated skulls and bones attest to complex mortuary practices. Stable carbon and nitrogen isotope analyses of 90 human, 48 faunal, and seven cereal samples provide a rich database for dietary reconstruction. The results point to a diet that was largely based on C3 plants with a limited contribution of herbivore or pig meat and/or dairy products. Divergent isotope ratios can be attributed to the consumption of chicken meat/eggs or seasonally available salmon. Moreover, the contribution of C4 plants, supposedly millet, to human diets is well documented at Basel as well as at other central European Iron Age sites. We found no significant dietary distinctions between males and females. In children, indications for breastfeeding terminate between 1.5 and about 4 years of age, with isotopic differences emerging with regard to the investigated skeletal elements. The stable isotope data from different burial contexts, forms of mortuary practice, and presence or type of funerary objects overlap widely, providing only tentative indications for dietary differentiation within the living population. These findings distinguish Basel-Gasfabrik from other Iron Age sites and call for further integrative studies for deciphering the complex mechanisms behind the highly differentiated mortuary practices in the late Iron Age.
Development of agriculture is often assumed to be accompanied by a decline in residential mobility, and sedentism is frequently proposed to provide the basis for economic intensification, population growth and increasing social complexity. In Britain, however, the nature of the agricultural transition (ca 4000 BC) and its effect on residence patterns has been intensely debated. Some authors attribute the transition to the arrival of populations who practised a system of sedentary intensive mixed farming similar to that of the very earliest agricultural regimes in central Europe, ca 5500 BC, with cultivation of crops in fixed plots and livestock keeping close to permanently occupied farmsteads. Others argue that local hunter-gatherers within Britain adopted selected elements of a farming economy and retained a mobile way of life. We use strontium and oxygen isotope analysis of tooth enamel from an Early Neolithic burial population in Gloucestershire, England, to evaluate the residence patterns of early farmers. Our results are consistent with the hypothesis that early farming communities in Britain were residentially mobile and were not fully sedentary. Results highlight the diverse nature of settlement strategies associated with early farming in Europe and are of wider significance to understanding the effect of the transition to agriculture on residence patterns.
Im ersten Teil des Aufsatzes werden quartärgeologisch-bodenkundliche Untersuchungsergebnisse an Aufschlüssen der linksrheinischen Niederterrasse bei Basel vorgelegt. Im zweiten Teil werden Resultate mikromorphologischer Analysen an archäologischen Sedimenten der Fundstelle Basel-Gasfabrik diskutiert. Aufgrund der künstlich gekappten Bodenprofile steht fest. dass zu Beginn der latenezeitlichen Besiedlung ein beträchtlicher Abtrag von Bodenmaterial stattgefunden hat. An der Basis der archäologischen Schichtenfolge liess sich indessen mehrfach ein Stampflehmboden beobachten, der mit Hausstrukturen in Verbindung gestanden haben muss.
The discovery of the mortal remains of King Richard III provide an opportunity to learn more about his lifestyle, including his origins and movements and his dietary history; particularly focussing on the changes that Kingship brought. We analysed bioapatite and collagen from sections of two teeth which formed during Richard's childhood and early adolescence, and from two bones: the femur (which averages long-term conditions), and the rib (which remodels faster and represents the last few years of life). We applied multi element isotope techniques to reconstruct a full life history. The isotopes initially concur with Richard's known origins in Northamptonshire but suggest that he had moved out of eastern England by age seven, and resided further west, possibly the Welsh Marches. In terms of his diet, there is a significant shift in the nitrogen, but not carbon isotope values, towards the end of his life, which we suggest could be explained by an increase in consumption of luxury items such as game birds and freshwater fish. His oxygen isotope values also rise towards the end of his life and as we know he did not relocate during this time, we suggest the changes could be brought about by increased wine consumption. This is the first suggestion of wine affecting the oxygen isotope composition of an individual and thus has wider implications for isotope-based palaeodietary and migration reconstructions.
Strontium isotope ratios (87Sr/86Sr) are a key
geochemical tracer used in a wide range of fields including archaeology,
ecology, food and forensic sciences. These applications are based on the
principle that the Sr isotopic ratios of natural materials reflect the
sources of strontium available during their formation. A major
constraint for current studies is the lack of robust reference maps to
evaluate the source of strontium isotope ratios measured in the samples.
Here we provide a new dataset of bioavailable Sr isotope ratios for the
major geologic units of France, based on plant and soil samples (Pangaea
data repository doi:10.1594/PANGAEA.819142 ).
The IRHUM (Isotopic Reconstruction of Human Migration) database is a web
platform to access, explore and map our dataset. The database provides
the spatial context and metadata for each sample, allowing the user to
evaluate the suitability of the sample for their specific study. In
addition, it allows users to upload and share their own datasets and
data products, which will enhance collaboration across the different
research fields. This article describes the sampling and analytical
methods used to generate the dataset and how to use and access of the
dataset through the IRHUM database. Any interpretation of the isotope
dataset is outside the scope of this publication.
Der vielgestaltige Umgang mit Toten ist ein auffälliges Charakteristikum der Spätlatènezeit. Die protourbane Siedlung Basel-Gasfabrik bietet mit zwei Körpergräberfeldern sowie vollständigen Skeletten und isolierten Knochen aus Siedlungskontexten ideale Vorraussetzungen, Hypothesen zur Totenbehandlung zu entwickeln und zu überprüfen. Die demographische Struktur der Individuen von den Gräberfeldern zeigt, dass hier ein repräsentativer Ausschnitt der ehemaligen Lebendbevölkerung vorliegt. Zahlreiche Kindergräber belegen eine hohe Kindersterblichkeit. Beigaben wie Keramikgefässe, eiserne Fibeln, Glasperlen usw. finden sich häufiger in Gräbern von Kindern als von Erwachsenen. In der Siedlung sind unter den vollständigen Skeletten aus Gruben und Brunnen ebenso wie unter den isolierten Knochen jüngere Individuen unterrepräsentiert. Zahlreiche isolierte Skelettelemente weisen Spuren peri- und postmortaler Manipulationen wie Carnivorenverbiss, Schnitt- und Brandspuren auf. Andere Knochen wurden dagegen schnell einsedimentiert, so dass sich Hinweise auf unterschiedliche Prozesse ergeben, die in den Verbleib menschlicher Skelettreste in Siedlungskontexten münden. Untersuchungen der archäologischen Befundkontexte sowie molekulargenetische und geochemische Analysen sollen Aufschluss darüber geben, welche Selektionskriterien der differentiellen Totenbehandlung zu Grunde liegen. Es soll versucht werden, wiederkehrende Handlungsmuster zu rekonstruieren und Rückschlüsse zu ziehen auf die ehemalige Lebendgemeinschaft in der Spätlatènezeit.
One striking characteristic of the Late La Tène period is the variegated handling of the dead. The Basel-Gasfabrik Late La Tène site has two inhumation cemeteries as well as complete burials in pits and wells and numerous isolated human skeletal remains from a variety of settlement features, making it possible to develop and test hypotheses on the differential handling of the dead. The demographic profile of the individuals interred in the burial grounds shows these to represent a valid segment of the former population. Infant mortality was high. Grave goods such as ceramic vessels, iron brooches and glass beads are more frequent in childrens graves. Among the human remains found in settlement contexts individuals below the age of 20 are underrepresented. Numerous isolated bones exhibit marks of peri- and postmortem manipulations like carnivore gnawing, cut- or scorch marks. In contrast, other bones were embedded quickly. This hints at the existence of several processes which resulted in the presence of human skeletal remains in settlement features. The examination of archeological contexts associated with human remains as well as molecular and geochemical analyses look at possible criteria for selecting individuals submitted to the differential handling. They also aim at identifying recurring patterns of behavior, thus attempting to draw conclusions on the former living community of the late Iron Age.
The mean depth of Sr and water uptake in mixed Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) stands was investigated, using natural variations of 87Sr/86Sr and 18O/16O in soils in relation to depth. Three spruce-pine pairs were studied on a podzol and a peat site in Northern Sweden. Tree leaf and wood, as well as soils, soil solutions and roots below each tree were analysed for Sr and Ca concentrations and 87Sr/86Sr ratio. The 18O/16O ratio was also determined in xylem sap and soil solutions in relation to depth. Soil solution 18O/16O decreased in relation to depth. Comparing with xylem sap 18O/16O data indicated a deeper uptake of soil water by pine than spruce on the podzol site and a superficial uptake by both species on the peat. The 87Sr/86Sr ratio of bioavailable Sr generally increased in soils in relation to depth. Contrastingly, the 87Sr/86Sr ratio in spruce wood was generally higher than in pine wood suggesting a deeper uptake of Sr by spruce. But the 87Sr/86Sr ratio and concentrations of bioavailable Sr were systematically higher below spruce than below pine. In order to explain these unexpected results, we built a simple flux model to investigate the possible effects of interspecific variations in Sr cycling, soil mineral weathering and depth of Sr uptake on soil and tree 87Sr/86Sr ratio. At the study sites, spruce cycled in litterfall up to 12 times more strontium than pine. The use of the model showed that this difference in Sr cycling could alone explain higher isotopic signatures of trees and topsoils below spruce. Besides, high isotopic signatures of roots in the A/E horizons below spruce led us to hypothesise a species-specific weathering process. Finally, the comparison between the 87Sr/86Sr ratios in wood and root or soil solutions below each species suggested that the average depth of Sr and water uptake were close, but irregular variations of the Sr isotopic ratio with depth reduce the accuracy of the results. Tree species strongly influence Sr isotopic ratios in boreal forest soils through differences in Sr cycling, and possibly through specific mineral weathering.
The response of fluvial systems to tectonic activity and climate change during the Late Pleistocene influenced sedimentary
processes and hence the conditions of river terraces formation. The northern Alpine foreland is well adapted for such studies
due to the high sediment input and the variety of depositional environments. This study focuses on sediments of a part of
the Rhine River in the area of Basel, at the Border between Switzerland, Germany and France. A detailed evolution of the Lower
Terrace is inferred from sedimentological, geomorphologic and pedological observations as well as historical documents, and
calibrated using different dating methods (optically stimulated luminescence, uranium series disequilibrium, radiocarbon).
The Lower Terrace was deposited during two periods (30–15 ka and 13–11 ka), which correlate with two cold climatic phases,
representing the Last Glaciation of the Alps and the Younger Dryas. These ages underline that main incision of the Lower Terrace
braidplain in the area of Basel is restricted to post Younger Dryas times, as sediments of that age (13–11 ka) are found atop
the highest levels. From then on, a flight of cut-terraces were formed with minor re-accumulation due to Holocene flood events.
These findings demonstrate that the surface of a terrace does not always represent the age of sediment aggradation, and this
should be remembered when using terraces to reconstruct the tectonic history of an area.
The two main sources of Ca in forest ecosystem are the mineral weathering release and atmospheric inputs. We use the 87Sr/86Sr isotopic ratio (Sr is a proxy for Ca) to determine the Ca contribution from rain input in two forest ecosystems (beech stands) growing on soils formed from parent materials with distinct total Ca contents and contrasted isotopic ratios: Pleistocene loess in Central Belgium (leached brown soil) with present-day 87Sr/86Sr =0.72788 and Lower Devonian shales and sandstones in Ardennes (ochreous brown earth) with 87Sr/86Sr = 0.76913. The 87Sr/86Sr ratios and the Ca and Sr contents were measured in rainwater, vegetation (beech wood growth rings and leaves) and main soil horizons (total, labile and HCl 0.1 M soluble forms). The relative contributions of atmospheric input and soil mineral weathering to vegetation were calculated using mixing equations. Calculations based on the Sr isotope ratios of rainwater (endmember 1; 87Sr/86Sr close to seawater: 0.7090), labile soil fraction (endmember 2; 87Sr/86Sr: 0.71332 to 0.71785) and beech wood (mixing compartment) indicate that about 50 % (Central Belgium) to 35 % (Ardennes) of Ca uptake originate from atmospheric inputs. The choice of the appropriate 87Sr/86Sr ratio for the weathering endmember is however critical. The isotopic composition of the mineral source is theoretically determined by the mineralogical composition of the soil and the relative weatherability of the Sr-bearing minerals. Due to soil processes (weathering and clay illuviation), the distribution of minerals in both soil profiles is not homogeneous and varies from horizon to horizon. Which horizons are relevant and which kind of soil extract (labile soil fraction, acid soluble fraction, total soil,...) should be selected for isotopic measurement of weathering endmember, is therefore questionable. The different ways of estimation are discussed. Quantitative mineralogical reconstitutions of soil horizons and isotopic data indicate preferential weathering of plagioclase (high Sr content with low 87Sr/86Sr) rather than mica or K-feldspar (high 87Sr/86Sr). Our results emphasize the importance of the Ca atmospheric contribution to the tree mineral nutrition in these forest ecosystems. It is plausible that acid depositions associated with decreasing input of atmospheric cations ("acid rains") could increase the depletion of soil available cation pool at a short-time scale.
There are two main models for the spatial organization of Linearbandkeramik (LBK, Old Neolithic, ca. 5.500—4.900 BC) animal husbandry that postulate either feeding domestic animals – especially cattle – in areas close to the settlement in combination with an intensive horticulture economy, or extensive animal tending with seasonal mobility (transhumance) to the low mountain ranges. The hypotheses rely on archaeobotanical data (macro remains and pollen), theories from economic history, archaeological results, and the emains of LBK domestic animals themselves. The following example from southwest Germany systematically examines these multiple perspectives and evaluates them in conjunction with current hypotheses about the spatial organization of LBK animal husbandry.
The main focus of the study is the oxygen and strontium isotope analysis of cattle teeth from three LBK settlements and human teeth from a cemetery. These samples provide information about seasonality (δ18O is temperature dependent) and location (87Sr/86Sr varies depending on geologic foundation).
The combination of the two different isotope systems from the enamel of the same tooth allows for a differenciation between seasonal mobility and a more sedentary pattern of animal husbandry, and a determination of the time of year and pasture locations used.
The cattle teeth from Vaihingen/Enz – one of the largest LBK settlements – mainly reflect a sedentary animal husbandry practice on fixed local loess or occasional (mostly summer) pasture in river valleys (or Muschelkalk areas). Evidence for seasonal pasture transhumance in the low mountain ranges is rare.
In Stuttgart‐Mühlhausen, one of the smaller settlements in the Neckar area, where surrounding regions have a strong loess character, animal husbandry was concentrated in river and stream valleys. Evidence for seasonal mobility and low mountain range use was not found.
The cattle from Hilzingen “Forsterbahnried” (Hegau region) were also largely sedentary, but
only some of them were kept on the locally typical Tertiary volcanic rock formations. A different portion of the cattle were either exclusively fed on Moraine formations near the settlement, or traded from a neighboring settlement without local volcanic rocks.
The results of the oxygen isotope analyses show a distribution of cattle births throughout the
year, which would minimize risk at birth, balance the use of summer and winter feed, and allow for year‐round slaughtering.
In addition to the investigation of animal teeth, the completed analyses of human teeth from the LBK cemetery at Stuttgart‐Mühlhausen “Viesenhäuser Hof” show a significant difference between men and women of the older LBK (Flomborn), as well as between burials of the older and younger LBK. Especially prominent are the systematic differences of Sr isotope ratios between tooth crowns with different mineralization times (early vs. late childhood) of the same individual. These results are discussed in terms of residence patterns and their connection with the individual’s absence from the settlement in late childhood and youth in the role of herdsmen.
Altogether, the results of the isotope analysis of LBK cattle teeth reflect heterogeneity in the animal husbandry and landuse strategies of LBK peoples. At the same time evidence for use of the low mountain ranges as specified in the model for seasonal transhumance is more rare, and evidence for the use of local resources in various habitats (loess areas or river valleys) dominate. These results are in agreement with a more intensive local economic orientation with narrower integration of cultivation and animal husbandry.
Human skeletal remains from Bell Beaker graves in southern Germany, Austria, the Czech Republic, and Hungary were analyzed for information on human migration. Strontium isotope ratios were measured in bone and tooth enamel to determine if these individuals had changed ‘geological’ residence during their lifetimes. Strontium isotopes vary among different types of rock. They enter the body through diet and are deposited in the skeleton. Tooth enamel forms during early childhood and does not change. Bone changes continually through life. Difference in the strontium isotope ratio between bone and enamel in the same individual indicates change in residence. Results from the analysis of 81 Bell Beaker individuals indicated that 51 had moved during their lifetime. Information on the geology of south-central Europe, the application of strontium isotope analysis, and the relevant Bell Beaker sites is provided along with discussion of the results of the study.
Strontium isotopes are a powerful tool for investigating the geographical origins of people and animals but assignment of provenance requires reference maps and databases. This paper presents a map of strontium isotope variations across Britain for use in archaeological and other studies, and is produced by direct measurement of strontium isotope compositions of biosphere components, predominantly plants. The map characterizes the biosphere signature of specific lithologies: a technique that is applicable worldwide. Marine-derived strontium, from both rainwater and coastal sea-splash and spray, is an important contribution to the British biosphere, particularly on the western seaboard, which is subject to high rainfall and prevailing westerly winds.
Supplementary material
Methods, full data table, and full-size version of Figure 1b are available at http://www.geolsoc.org.uk/SUP18388 .
Residential changes of people during the Migration Period are crucial for archaeological research. Within an extensive study of the migration of the Langobards, strontium isotope analysis was carried out on tooth enamel taken from 48 burials from the Thuringian cemeteries of Rathewitz and Obermöllern (Burgenlandkreis, Sachsen-Anhalt, Germany), which date to the late 5th–mid 6th century. Modern vegetation and water samples provided detailed information about the isotopic composition of the biologically available strontium of geological units in the area. Although the rich furnishing of the burials provides evidence for contacts with many different regions, only one individual (7.1 %) in Rathewitz and three (12.5 %) in Obermöllern are isotopically nonlocal to the sites. These individuals were buried among the locals and their graves were similarly equipped. In contrast, many nonlocal grave goods were found with isotopically local individuals, often in combination with local items or pieces indicating several different source areas. This suggests the existence of strong interregional ties among the members of the local elites. The cemeteries cannot overall be associated with newly arriving groups; rather, they resulted from a change of funeral customs of the indigenous population from cremation to inhumations or small-scale changes of the burial places. They reflect individual residential changes rather than large-scale movements of groups.
Many studies made in Europe and North America have shown an increasing depletion of exchangeable base cations that may cause tree nutritional deficiencies in sensitive soils. We use radial variation of strontium isotope in tree-rings (87Sr/86Sr ratio) to monitor possible changes in Ca sources for tree nutrition (Sr is used as an analog to Ca). The two main sources of Ca in forest stands are mineral weathering release and atmospheric inputs. Measurements in several forest stands in temperate regions show a steep decrease from pith to outer wood of the Sr isotope ratio from∼1870 to∼1920 except for stands developed on soils with a higher Ca status. This suggests a decrease of the weathering contribution (high 87Sr/86Sr ratio) when cations are displaced from the soil exchange complex by acid deposition at a rate faster than the replenishment of the cation pool by mineral weathering. This displacement enhances the atmospheric contribution, which is characterized by a low 87Sr/86Sr ratio. Tree-ring chronologies are an exceptional historic-timing record of chemical changes in the soil environment induced by atmospheric pollution. The reliability of the tree-ring recorder has been verified with a well-controlled nutritional perturbation in the context of a limed forest stand (with a known liming Sr isotopic signature). Our data suggest that forest ecosystems were affected by atmospheric inputs of strong acids earlier than previously thought.
The two main sources of Ca in forest ecosystems are mineral weathering release and atmospheric inputs. We use the 87Sr/86Sr isotopic ratio (Sr is used as a proxy for Ca) to determine the Ca contribution from atmospheric deposition input in two forest ecosystems (beech stands) growing on soils formed from parent materials with contrasting total Ca contents and isotopic ratios: Pleistocene loess in Central Belgium (acid leached soil) and Lower Devonian shales in the Ardenne Massif of High Belgium (ochreous brown earth). The 87Sr/86Sr ratio and the Ca and Sr contents were measured in bulk precipitation, in vegetation (beechwood growth rings and leaves) and in main soil horizons (total, acid-extractable and labile pools). The relative contributions of atmospheric input and soil mineral weathering to vegetation were calculated using mixing equations.
The natural Sr isotope composition of acid leached soils developed on loess, under beech forest, in central Belgium was used as a tracer of soil forming processes, in conjunction with physico-chemical and quantitative mineralogical investigations. Attention was focused on weathering and exchange processes, with special emphasis on the origin of the current soil exchangeable fraction and the influence of the atmospheric deposition and biological cycling on the calcium exchangeable pool (Sr acts as a proxy for Ca). The determination of 87Sr/86Sr ratios was made on the bulk soil, on the clay- and silt-size soil separates, on 0.1 m HCl extracts, on the labile pool, on the soil solution and on the bulk precipitation. The acid leached soil profiles are characterized by a sequence of weathering processes that is highlighted by both mineralogical and isotopic changes. From the calcareous unweathered loess (pH 7.5) to the uppermost soil horizons (pH < 4.0) the evolution of the 87Sr/86Sr isotope ratio clearly reflects: (i) the selective weathering of Ca-plagioclase (small 87Sr/86Sr ratio) and the increasing proportion of resistant K- and Rb-rich minerals (large 87Sr/86Sr ratio) in the uppermost soil horizons; and (ii) a downward translocation of clay minerals with a large isotopic ratio, a physical breakdown of muscovite and a non-congruent chemical weathering of K-feldspar. The influence of organic restitutions or atmospheric deposition is not significant. The comparison between the Sr isotopic signature of the soil solution, and the exchangeable and HCl-extractible soil fractions provides information about cation exchange efficiency, soil–water interaction and the origin of the exchangeable pool.
The total dissolved load of the Rhine river increases downstream due to the combined impact of natural and pollution loads. The natural background, controlled by geology, is soon swamped by pollution, particularly from salt and coal mining activities in Alsace and the Ruhr area. The Rhine is also a net source of CO2 from oxidation of excess organic productivity that is fuelled by nutrient pollution, a problem even more serious for some of its tributaries.
Strontium isotope analysis of archaeological skeletons has provided useful and exciting results in archaeology in the last 20 years, particularly by characterizing past human migration and mobility. This review covers the biogeochemical background, including the origin of strontium isotope compositions in rocks, weathering and hydrologic cycles that transport strontium, and biopurification of strontium from to soils, to plants, to animals and finally into the human skeleton, which is subject to diagenesis after burial. Spatial heterogeneity and mixing relations must often be accounted for, rather than simply ``matching'' a measured strontium isotope value to a presumed single-valued geologic source. The successes, limitations and future potential of the strontium isotope technique are illustrated through case studies from geochemistry, biogeochemistry, ecology and archaeology.
Depletion of calcium from forest soils has important implications for forest productivity and health. Ca is available to fine feeder roots from a number of soil organic and mineral sources, but identifying the primary source or changes of sources in response to environmental change is problematic. We used strontium isotope and alkaline earth element concentration ratios of trees and soils to discern the record of Ca sources for red spruce at a base-poor, acid deposition-impacted watershed. We measured 87Sr/86Sr and chemical compositions of cross-sectional stemwood cores of red spruce, other spruce tissues and sequential extracts of co-located soil samples. 87Sr/86Sr and Sr/Ba ratios together provide a tracer of alkaline earth element sources that distinguishes the plant-available fraction of the shallow organic soils from those of deeper organic and mineral soils. Ca/Sr ratios proved less diagnostic, due to within-tree processes that fractionate these elements from each other. Over the growth period from 1870 to 1960, 87Sr/86Sr and Sr/Ba ratios of stemwood samples became progressively more variable and on average trended toward values that considered together are characteristic of the uppermost forest floor. In detail the stemwood chemistry revealed an episode of simultaneous enhanced uptake of all alkaline earth elements during the growth period from 1930 to 1960, coincident with reported local and regional increases in atmospheric inputs of inorganic acidity. We attribute the temporal trends in stemwood chemistry to progressive shallowing of the effective depth of alkaline earth element uptake by fine roots over this growth period, due to preferential concentration of fine roots in the upper forest floor coupled with reduced nutrient uptake by roots in the lower organic and upper mineral soils in response to acid-induced aluminum toxicity. Although both increased atmospheric deposition and selective weathering of Ca-rich minerals such as apatite provide possible alternative explanations of aspects of the observed trends, the chemical buffering capacity of the forest floor-biomass pool limits their effectiveness as causal mechanisms.
The Basel-Gasfabrik site (Switzerland) is among the largest and best investigated proto-urban centres of the La Tène period (chiefly La Tène C2/D1; 200/150–80 BCE). Excavations revealed evidence of an urban lifestyle, crafts production as well as a multitude of imported goods. Human skeletal remains were recovered both from two cemeteries and from various settlement features. Strontium (87Sr/86Sr) and oxygen (δ18Op) isotope analyses aimed at an assessment of the role of residential changes in the makeup of the site's population, the positioning of Basel-Gasfabrik in local, regional, and long-distance networks, and the exploration of possible correlations between the complex mortuary practices and the individuals' residential history. The study involved 94 enamel samples from 54 human individuals, while archaeological animal teeth and modern vegetation and water samples provided baseline information. The 87Sr/86Sr and the δ18Op ratios of the human teeth varied widely between 0.70755 and 0.71655 and 14.7 and 19.3 ‰, respectively, with more variation among adult males and females than among juveniles. Both the archaeological setting and the isotope data attest to lively contacts of the central site to its hinterland, but also to distant regions, such as the Mediterranean. Differences in the isotope data of successively formed tooth crowns of some of the adult population point to residential changes in childhood. Possible explanations include fosterage as an important element in strengthening regional and interregional ties among Iron Age communities, settlement centralization, and mobile animal husbandry practices. However, areas of origin or patterns of mobility were not among the key factors which shaped the complex mortuary practices.
This chapter summarizes the results achieved in an attempt to contribute to bioarchaeological research aiming at the reconstruction of migration and culture transfer in a region of eminent archaeological importance in Europe, namely, the Inn-Eisack-Adige passage via the Brenner Pass in the European Alps. 219 archaeological animal bone samples of three residential species (Bos taurus, Sus scrofa, Cervus elaphus) from 30 archaeological sites covering the transalpine passage have been analysed in terms of δ¹⁸Ophosphate, ⁸⁷Sr/⁸⁶Sr, ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁸Pb/²⁰⁷Pb and ²⁰⁶Pb/²⁰⁷Pb, thus generating a multi-isotope fingerprint. All measurement data and the laboratory processing methods are reported in detail. The isotopic map based on the spatial distribution of isotopic signatures in the bone finds is augmented by modern reference samples (water, soil, vegetation) to verify whether the choice of animal skeletal samples was appropriate and to perform a pilot study leading to a predictive model for ⁸⁷Sr/⁸⁶Sr isotopic ratios in local bioarchaeological specimens. Univariate statistics for each single isotopic signature and the related maps with the respective spatial distribution are presented.
For a few decades archaeologists have been measuring 87Sr/86Sr in human teeth to explore human mobility, mostly by inferring that 87Sr/86Sr outliers represent individuals who immigrated into archaeological sites. Although the utility of the method is incontestable, the applications are beginning to outrun their theoretical foundations. Enormous efforts are currently being made to match specific isotope ratios with broad geographic regions, or “isoscapes,” connecting the underlying geology with the ratios in human teeth. However, a close examination of the distribution of 87Sr/86Sr reveals that there is enormous local variation in the geosphere, that biological ratios can differ significantly from those expected from the geology, that human ratios can vary according to diet, and that diet can include isotope inputs from beyond the place of birth. Thus a direct, empirical assessment of the human data can yield a more accurate “local” human value than can isoscape models. An appreciation of such details can help avoid erroneous inferences of mobility and yield more anthropologically nuanced results.
An overview of the analyses and archaeometric interpretations of isotopic compositions of bones as tracers of the geographic origin of individual vertebrates are given. The application of oxygen and strontium isotope ratios as tools for the determination of habitat and reconstruction of migration are demonstrated for an early medieval equid skeleton from deposits of the Rhine river near Frankenthal, Germany. The geochemical results are compared to those of skeletal remains from late Pleistocene mammals of the Rhine gravels. In this context, postmortem diagenetic alteration of primary elemental and isotopic compositions of bone will be discussed and conclusions made on the analyses of chemical indicators most suitable for archaeometric interpretations.
The Early Bronze Age necropolis of Singen (Hohentwiel), located near Lake Constance, represents a population from a period of technological transition in southwestern Germany. The site contains several graves with metal artefacts that originated in other parts of Central and Western Europe, and therefore these could be interpreted as being the graves of non‐local individuals. The purpose of this study was to investigate this possibility through the application of isotopic analysis. The ratios of strontium and oxygen isotopes in human enamel reflect the geological origin of food and drinking water consumed during enamel formation in early life stages. Additionally, the ratio of sulphur isotopes from bone collagen reflects the origin of foods consumed during the last 10–20 years of life of an adult individual. We used these three isotope systems to attempt to identify local and non‐local individuals at the site. We found that the isotope ratios of Sr, O and S of the humans were relatively homogeneous and generally correspond to the isotope signature of the local geology, climate and environment. We conclude that the sampled population is of local origin and does not show patterns of individual mobility, even though there is evidence for long‐distance trade and exchange of the metal artefacts at this site.
Every scientific field evolves its own terminology to accomodate (more or less) its particular interests and requirements (Swales 1990). In order to facilitate a dialog within and among disciplines, it is necessary to use an accepted nomenclature as well as standardized abbreviations and signs. Nonetheless, an “officially” implemented nomenclature is not always recognized by all members of the scientific community. This leads to the unsatisfying situation wherein several different terminologies are in parallel use, thus often causing misunderstandings. In anatomy, for example, a standard Latin nomenclature was compiled for the first time in 1895 (Baseler Anatomische Nomenklatur [Basle Nomina Anatomica, B.N.A.]). In an attempt to improve upon the B.N.A., the Anatomical Society of Great Britain and Ireland presented a Birmingham Revision in 1933 (in Latin and English), which had been widely used in the English-speaking world, while the German Anatomical Society (Deutsche Anatomische Gesellschaft) adopted its own revision in 1935 (in Latin) which became known as the Jena Nomina Anatomica (J.N.A.) (Kopsch 1941).
The investigation of prehistoric human migration from the measurement of Sr-isotope ratios within preserved tissue is critically dependent on the preservation of biogenic Sr. A number of recent studies have involved isotope ratio measurements on samples of archaeological tooth and bone, but doubt remains as to the extent of diagenesis in various skeletal tissues and the effectiveness of procedures designed to decontaminate them. The authors have compared Sr abundance and isotope ratios in enamel and dentine from archaeological teeth in order to assess the integrity of the biogenic Sr signal preserved within the respective tissues. It is concluded that enamel appears, in most cases, to be a reliable reservoir of biogenic Sr, but that dentine, and by implication bone, is not. The diagenesis of dentine is highly variable even between burials within a single site. For the majority of teeth, dentine diagenesis was not simply by addition of soil-derived Sr, but involved substantial, sometimes complete, turnover of the original biogenic material. It is suggested that, for most of the samples investigated, current decontamination techniques may not have been effective in isolating biogenic Sr from dentine. Similar considerations are likely to apply to archaeological and fossil bone, but the possibility arises to use dentine and enamel measurements to assess the effectiveness of decontamination procedures which may then be used for bone.
87Sr/86Sr of archaeological skeletal tissues are increasingly used to reconstruct residential mobility and migration, but the post mortem preservation of biogenic Sr is often uncertain. Sample pre-treatment regimes, notably ‘solubility profiling’, have been used to remove diagenetic Sr prior to analysis, but doubts remain over their effectiveness. The investigation examines the effectiveness of solubility profiling by comparing the Sr content and 87Sr/86Sr composition of bone, dentine and enamel from two archaeological juveniles (Blackfriars, UK) before and after attempted decontamination. For both individuals leached samples of cortical bone and dentine had similar 87Sr/86Sr to those of soil leachates from the burial site, and are therefore thought to represent diagenetic 87Sr/86Sr. For both individuals samples of treated dental enamel have 87Sr/86Sr considerably more or less radiogenic than the soil leachates and other tissues. These are considered representative of biogenic Sr, i.e. Sr acquired in vivo. In effect, solubility profiling should have resulted in 87Sr/86Sr that were similar for all 3 tissues types and close to those of the untreated enamel. Experimental results show that tooth enamel 87Sr/86Sr remained largely unaffected by solubility profiling, and the process did not significantly alter the final 87Sr/86Sr of either dentine or cortical bone. It is concluded that the technique was ineffective in facilitating the recovery of biogenic Sr from these tissues.
To assess the contribution of deep soil horizons to the mineral supply of trees, we investigated the natural variation in the87 Sr/86Sr isotopic ratio of plant-available strontium with soil depth. In three sites of North-western Spain, this ratio increased with soil depth. The comparison of isotopic ratios of tree leaves and roots at different depths showed that most of the Sr accumulation in Eucalyptus globulus and Pinus pinaster growing on shallow and poor soils in this rainy climate originated from the upper soil layers. As Ca and Sr behave similarly in the soil-plant system, this conclusion can be applied to Ca. This superficial uptake is attributed to the low availability of Sr and Ca in the soil as well as to the shortness of the drought period as compared to the length of the growth period. This technique appears to offer a promising way of studying relative root distributions in soils and plant competition for nutrients.
Strontium isotope ratios (87Sr/86Sr) are used as a geochemical tracer in
a wide range of fields including archaeology, ecology, soil, food and
forensic sciences. These applications are based on the principle that
strontium isotopic ratios of materials reflect the geological sources of
the strontium, which were available during its formation. Geologic
regions with distinct strontium isotope ranges, which depend on their
age and composition, can be differentiated. A major constraint for
current studies is the lack of robust reference maps to evaluate the
strontium isotope ratios measured in the samples. The aim of the
IRHUM (isotopic reconstruction of human migration) database is to
provide a reference map of bioavailable strontium isotope ratios for
continental France. The current dataset contains 400 sample locations
covering the major geologic units of the Paris and Aquitaine Basin, the
Massif Central, and the Pyrenees. At each site soil and plant samples
have been collected to cover the whole range of strontium ratios at a
specific location. The database is available online at
www.rses.anu.edu.au/research-areas/archaeogeochemistry and contains the
bioavailable strontium isotope data as well as major and trace element
concentrations for soil and plant samples. Strontium isotopes were
analysed using a Neptune multi-collector inductively-coupled plasma mass
spectrometer (MC-ICP-MS) and elemental concentrations with a Varian
Vista Pro Axial ICP-AES (inductively-coupled plasma atomic emission
spectrometer). In addition, IRHUM provides spatial context for each
sample, including background geology, field observations and soil
descriptions. This metadata allows users to evaluate the suitability of
a specific data point for their study. The IRHUM database fills an
important gap between high resolution studies from specific sites (e.g.
archaeological sites), to the very broad geochemical mapping of Europe.
Thus it provides an excellent tool to evaluate the regional context of a
sample and complement more closed spaced studies. New results will be
added to the database continuously with the aim of covering all major
geologic units of France within the next year.
We used 87Sr/86Sr as a proxy for Ca to apportion the contribution of atmospheric deposition and soil mineral
weathering sources to the Ca pools in trees in a small forested watershed of southern Quebec. The effects of
topography and forest stand composition were assessed by dividing the watershed into three study zones
representing two elevations and differences in tree species. Apportionment calculations show that all tree
species studied contained Ca that is dominantly sourced from soil mineral weathering (averaging 85%), due
to the presence in the soils of easily weathered Ca-bearing minerals such as calcite and apatite as well as the
relatively deep rooting habits (reaching the mineral soil) of the tree species. Calcium pools in trees are shifted
towards the atmospheric component on hilltops due to the filtering of dry aerosols of the tree canopies which
are more exposed to atmospheric circulation than trees at the bottom of the slopes, although some variability
in soil bulk chemistry and mineralogy in the watershed obscures the full extent of this phenomenon. The
buildup and recycling of Ca in the soil-vegetation system, with the forest floor acting as the major accessible
Ca pool for the tree roots, must be considered when interpreting apportionment calculations. This work
supports other Ca cycling models in forests suggesting that topography can influence the balance of Ca
captured from atmospheric sources by trees, even in cases where mineral weathering is the dominant source
of Ca nutrition in trees.
This paper determines the weathering and atmospheric contributions of Ca in surface water from a small spruce forested silicate catchment (N–E France) receiving acid atmospheric inputs. The bedrock is a granite with K-feldspar and albite as dominant phases. The calcium content in plagioclase is low and the Ca/Na ratio in surface water is high, reflecting other sources of calcium from those expected from the weathering of major mineral phases. The biotite content is low. Only traces of apatite were detected while no calcite was found in spite of a major hydrothermal event having affected the granite. The strontium isotopic ratio 87Sr/86Sr and Sr content was used as a tracer of weathering and was determined in minerals and bulk bedrock, open field precipitation, throughfall, soil solution, spring and stream water. The Sr isotopic ratio of the reacting weathering end-member was predicted by simulating the alteration of the granite minerals by incorporating strontium into the water–rock interaction kinetic code KINDIS. In the early stages of water–rock interaction, K-feldspar and biotite strongly influence the isotopic composition of the weathering solution whereas, the Na-rich plagioclase appears to be the main long-term reactive weathering end-member. Approximately 50% of dissolved Sr in streamwater are atmospherically derived. The 87Sr/86Sr ratios of exchangeable Sr in the fine fraction at 1-m depth from a soil profile indicate that the amount of exchangeable Sr seems essentially controlled by atmospheric inputs. The exception is the deep saprolite where weathering processes could supply the Sr (and Ca). Na-Plagioclase weathering obviously control the chemistry and the isotopic composition of surface waters. The weathering of trace mineral plays a secondary role, the exception is for apatite when plagioclase is absent. Our hydrochemical, mineralogical and isotopic investigations show that a major part of the strong Ca losses detected in catchment hydrochemical budgets that result from the neutralization of acid precipitation has an atmospheric origin. Consequently, in the long term, in such areas, the availability of such an exchangeable base cation might be strongly limited and surface waters consequently acidified.
Strontium isotope analysis of bone and tooth enamel from prehistoric human skeletons is an important new technique used to address questions regarding migration. Two problems arise in such investigations: (1) levels of strontium isotope ratios in local bedrock, soil, water, plants and animals are variable; and (2) a range of values in human bone and enamel data make it difficult to distinguish some migrants from locals. Analysis of the bones of small animals provides a robust measure of local strontium isotope ratios and a reliable, if conservative, means for determining confidence limits for distinguishing migrants. Data from various geographical areas are presented here in a discussion of variability in strontium isotope values. Examples are provided using modern and prehistoric materials. We conclude with the recommendation that studies involving strontium isotope analysis should incorporate small animal samples for comparative purposes whenever possible.
In this paper Sr isotope signatures are reported for 192 surface water (lakes/ponds and rivers/creeks) samples from within Denmark and an isotope distribution map is presented that may serve as a base for provenance applications, including archaeological migration studies, ground water – surface water – seawater interaction/contamination monitoring, and potentially for agricultural applications, including cases of authenticity proof for particular food products. The Sr isotopic compositions of surface waters range from 87Sr/86Sr = 0.7078 to 0.7125 (average 0.7096 ± 0.0016; 2σ). This average value lies above the range of 87Sr/86Sr values between 0.7078 and 0.7082 expected from Late Cretaceous to Early Tertiary (Oligocene) limestones which form the dominant bedrock type in a NW–SE trending belt in Denmark. The elevated 87Sr/86Sr signatures >∼0.7095 are explained by additions to the surface waters of radiogenic Sr predominantly derived from the near-surface weathering and wash-out of Quarternary glaciogenic tills and soils deposited and formed during and after the last two ice age stages (Saale and Weichsel). The Sr isotopic compositions and concentrations of the surface waters can, therefore, best be modeled by a two-component mixing involving carbonaceous bedrock and glaciogenic cover sediments as the two predominant Sr sources. A feasibility study for using Sr isotopic compositions of surface waters as a proxy for bio-available Sr signatures was conducted in a representative test area on Zealand (Land of Legends, Lejre) where there is no use and application of commercial fertilizers. It is demonstrated that the Sr isotopic signatures of lake waters from within this area are slightly higher (but statistically still indistinguishable) from the average value defined by snail shells and soil leachates considered to characterize the true bio-available Sr. In combination with results from other studies, this is interpreted to reflect the wash-out of Sr with a higher 87Sr/86Sr signature released by weathering in the topsoils into the saturated water tables, a component which is consequently not readily transferred into the shallow-rooting plants and into small herbivores feeding on them. Since drinking water is a likely important source of Sr uptake of humans and larger animals, the contention is that a surface water isotopic composition can potentially characterize the bio-available component relevant for human and carnivorous large animals. Spline functions and ordinary linear kriging were used for modeling the geographic distribution of bio-available Sr isotopes over territorial Denmark. As expected, based on the two-source mixing scenario, the water 87Sr/86Sr ratio contour maps (with some notable exceptions) neither mirror the pre-Quarternary bedrock geology nor a (Pleistocene) soil-type distribution map of Denmark.As a conservative suggestion, the use of the average 87Sr/86Sr ratio of 0.7096 ± 0.0015 (2σ) is recommended as an average for bio-available Sr from within Denmark (Bornholm excluded) for human and larger animals and as a confidence band for distinguishing “local” from “non-local” signatures in archaeological provenance studies. The study also reveals that the average 87Sr/86Sr ratio of ∼0.7088 defined from soil extracts and small herbivores lies approximately 0.15% lower than that defined by the surface waters. The authors recommend using this lower value as a “local”–“non-local” discriminator for food and plant authenticity control in agricultural applications.Research highlights► Strontium isotope data of 192 surface waters from Denmark. ► Geographic baseline distribution of bio-available fractions. ► Applicable for provenance studies within archaeology, geology, agriculture and hydrology. ► Proposal of a band of strontium isotope values to characterize “local” Danish signatures.
(87)Sr/(86)Sr reference maps (isoscapes) are a key tool for investigating past human and animal migrations. However, there is little understanding of which biosphere samples are best proxies for local bioavailable Sr when dealing with movements of past populations. In this study, biological and geological samples (ground vegetation, tree leaves, rock leachates, water, soil extracts, as well as modern and archeological animal teeth and snail shells) were collected in the vicinity of two early medieval cemeteries ("Thuringians", 5-6th century AD) in central Germany, in order to characterize (87)Sr/(86)Sr of the local biosphere. Animal tooth enamel is not appropriate in this specific context to provide a reliable (87)Sr/(86)Sr baseline for investigating past human migration. Archeological faunal teeth data (pig, sheep/goat, and cattle) indicates a different feeding area compared to that of the human population and modern deer teeth (87)Sr/(86)Sr suggest the influence of chemical fertilizers. Soil leachates do not yield consistent (87)Sr/(86)Sr, and (87)Sr/(86)Sr of snail shells are biased towards values for soil carbonates. In contrast, water and vegetation samples seem to provide the most accurate estimates of bioavailable (87)Sr/(86)Sr to generate Sr isoscapes in the study area. Long-term environmental archives of bioavailable (87)Sr/(86)Sr such as freshwater bivalve shells and tree cores were examined in order to track potential historic anthropogenic contamination of the water and the vegetation. The data obtained from the archeological bivalve shells show that the modern rivers yield (87)Sr/(86)Sr ratios which are similar to those of the past. However, the tree cores registered decreasing (87)Sr/(86)Sr values over time towards present day likely mirroring anthropogenic activities such as forest liming, coal mining and/or soil acidification. The comparison of (87)Sr/(86)Sr of the Thuringian skeletons excavated in the same area also shows that the vegetation samples are very likely anthropogenically influenced to some extent, affecting especially (87)Sr/(86)Sr of the shallow rooted plants.
In order to interpret strontium and oxygen isotope values in Neolithic human skeletons analysed previously, we begin to map the biologically available strontium, carbon and oxygen isotopic signatures of prehistoric southern Germany by analysing tooth enamel of pigs from archaeological sites distributed around the region. The mapping shows a marked upland–lowland difference in biologically available87Sr/86Sr values, ranging between 0.7086 and 0.7103 in the sedimentary lowlands, and from 0.710 to as high as 0.722 in the crystalline uplands of the Odenwald, the Black Forest and the Bavarian Forest. In addition, carbon isotopes in the carbonate fraction of pig enamel were generally about 1–2 more enriched in13C in the uplands. Despite the expected depletion of18O with altitude, oxygen isotopes in pig enamel showed little correlation with site altitude, although for pig samples not older than the Iron Age there was some geographical correlation withδ18O patterns in modern precipitation.