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Keywords:

  • BRONZE AGE;
  • 87Sr/86Sr;
  • δ18O;
  • ISOTOPES;
  • MIGRATION;
  • BEAKER;
  • STONEHENGE

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

Contrasting lifestyles are recorded by the isotope composition of Bronze Age Beaker people (c. 2500–2000 bc) from three burial sites (Boscombe Down, Normanton Down and the ditch around Stonehenge) at or near to the Stonehenge monument in Wiltshire, southern England. Seven individuals (three adults, a sub-adult, two juveniles and an infant) were recovered from a single grave at Boscombe Down. Strontium and oxygen isotope analysis of tooth enamel from two teeth (a premolar and third molar) from each of three of the adults in this grave (referred to as Boscombe Bowmen) show that they had all shared a pattern of mobility and migration during their lives. The three adult males spent their early childhood (as represented by data from the premolar teeth) in an area with a radiogenic 87Sr/86Sr isotope signature of around 0.7135. They each then moved, during early adolescence (as represented by the third molar results), to a less radiogenic area, where they acquired an 87Sr/86Sr signature of around 0.7112. This implies that they must then have travelled to the Stonehenge area of Wiltshire at a later time in their lives. Wales provides the closest area with rocks that supply suitable 87Sr/86Sr ratios and δ18O isotope compositions for these individuals, although other areas of Palaeozoic rock, such as Scotland and parts of Europe, cannot be ruled out.

Enamel from the two juveniles from the Boscombe Down burial yields 87Sr/86Sr ratios of 0.7098 and 0.7099, and strontium concentrations for both of 55 ppm. The very close match of the data for the two juveniles supports the possibility that they were raised in the same environment. The difference in strontium isotope data between the juveniles and three adult males described above shows that the children did not come from the same homeland as the adults with whom they share a grave.

The two adult males from the single burials at Normanton Down, and from Stonehenge itself, had static lifestyles and show no evidence of migration, in contrast to the Boscombe Bowmen. Their oxygen and strontium data are consistent with a childhood in the Stonehenge area.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

The fortuitous discovery of several Bronze Age burials in Wiltshire, England, near to Stonehenge (Fig. 1), has led to the best evidence yet recorded of migration of individuals during this period. The Bronze Age was a time of great change in Britain and is marked by new burial practices, with grave goods including a distinctive style of pottery, known as Beakers and/or artefacts of bronze, copper or gold. It is commonly believed that metalworking was introduced by immigrants from Continental Europe after 2500 bc. Archaeologists often equate the widespread distribution of this distinctive style of burial with a distinct group of people. These people are often referred to as the ‘Beaker folk’ and the earliest stages of the Bronze Age are often known as ‘the Beaker Period.’

image

Figure 1. Location map showing the positions of the burial sites described in this paper in relation to Stonehenge.

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A question commonly asked about cultural change is whether it was caused by the influx of individuals or whether it was more a social change caused by contacts with other cultures (Harrison 1980; Brodie 1998). Although there are documented examples of migration in historical times (e.g., the Anglo-Saxons), until recently is has been difficult to assess the extent of human movement during the much longer prehistoric period except through circumstantial evidence; for example, in artefactual remains or similarities in burial rites.

Isotope studies are starting to shed light on human movement and separate this from the transport of artefacts. This is because the technique can be applied directly to human remains. Montgomery et al. (2000) used strontium and lead isotopes from the tooth enamel of four Neolithic burials in Dorset (c. 3000 bc) to demonstrate mobility during the lifetime of the group, and the technique is being applied successfully to an increasing number of studies worldwide. Recent examples include Price et al. (2002) (Europe), Evans and Tatham (2004) (England), Hodell et al. (2004) (South America), Price et al. (2004) (Europe) and Montgomery et al. (2005) (England).

ARCHAEOLOGICAL DESCRIPTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

Three early Bronze Age graves in the vicinity of Stonehenge were excavated. Two of these, at Normanton Down and at Stonehenge, in the ditch of the henge, were typical ‘Beaker burials’: single adult male burials with a small number of distinctive objects.

The third grave was more unusual. It was a collective burial that contained bones from seven individuals; three adult males, a sub-adult, two juveniles, and an infant, who had been cremated. Pieces from at least seven Beaker pots and a number of other objects had been placed with the dead. Only one of the adult burials was complete and articulated. The other adult males were represented by a selection of their bones and it appears that they had been interred or exposed previously. The cremated infant was aged between 2 and 4; the two juveniles were aged between 5–6 and 6–7 years respectively. The burial of the 6–7 year old was found at a higher level in the grave and appears to have been inserted into the grave at a later date. Collective burials involving secondary burial are extremely rare in Beaker graves in southern England. Osteological evidence suggests that the adult males, the sub-adult and the oldest juvenile could have come from a common population (Fitzpatrick 2004). The presence of flint arrowheads in the grave led to the adult males being called the ‘Boscombe Bowmen’.

THE AIM OF THE STUDY

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

Our decision to use strontium and oxygen isotopes to study the possible origins of the individuals from the three burial sites was prompted by the results of an earlier study undertaken on two individuals from a nearby Bronze Age burial site (preliminary description in Fitzpatrick 2003). One individual from this study, the ‘Amesbury Archer’ (Fig. 1), was given the richest burial of this age in Britain. The δ18O drinking water values calculated from his tooth phosphate oxygen isotope composition suggested that he spent his childhood in an area that was climatically cooler than Britain, probably in central Europe. Our aim was to see if the burials from Boscombe Down, Normanton Down and the Stonehenge ditch yielded individuals with a similar non-local affinity.

THE CHOICE OF TEETH

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

Two teeth were selected (a second premolar and a third molar) from the three adults from Boscombe Down and from each of the adults from Normanton Down and Stonehenge in order to assess the environment of the individuals at two time points in their development. Unerupted premolars were taken from two of the Boscombe juveniles, but no samples were available from the sub-adult and the cremated infant. The exact time of mineralization of individual teeth is greatly debated, as is the time that it takes for each tooth to mineralize (Hillson 1996; Montgomery 2002). It is known, however, that the premolars mineralize, and therefore close isotopically, before the third molars between 3–6 years of age (Hillson 1996). The third molars exhibit the most variability. They are the last teeth to erupt and they probably mineralize between 9 and 13 years of age. What is significant for this study is that the premolars form first in early childhood and the third molars form several years later, perhaps as late as early adolescence.

MIGRATION STUDIES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

Migration studies in humans using tooth enamel are restricted to movements during childhood, as this is the period during which the teeth mineralize and lock in the isotope evidence for such studies. Each tooth is a snapshot of a particular time in the person's childhood development. Human enamel does not appear to show isotope heterogeneity. There is little data on this subject, but Montgomery (2002) showed that the Sr isotope composition of a single tooth reproduced to within ± 0.002% (2σ, n= 4) for a secondary tooth and ± 0.003–0.005% (2σ, n= 3) for deciduous teeth. In this respect, human tooth enamel differs significantly from certain animal teeth, particularly large herbivores, where the enamel continues to mineralize for several years after eruption. Ballasse (2003) has demonstrated stable isotope zonation along the growth axes of such teeth. The interpretation of human strontium isotope data is therefore based on the assumption that the teeth are snapshots of the averaged intake of strontium during the mineralization of each tooth during childhood.

THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

The oxygen isotope composition of biophosphate is directly related to that of ingested (drinking) water, and as drinking water values are known to vary with climatic zones (Longinelli 1984; Luz et al. 1984; Lécolle 1985; Rozanski et al. 1993; Darling et al. 2003), the oxygen isotope composition of tooth enamel provides information on the climatic environment in which people lived. Equations such as those in Levinson et al. (1987), Luz et al. (1984) or Longinelli (1984) can be used to take into account the metabolic fractionation effects of the body and convert the measured values in the tooth enamel into the corresponding drinking water values. However, these equations can result in significantly different drinking water values (Chenery 2005). Our approach in this paper to the interpretation of the oxygen isotope data is to make direct comparisons between the measured values of tooth enamel presented in this study and published data sets for populations from known sites and historical times. This approach is in its infancy, but as data sets are accumulated this may turn out to be a more valid approach than trying to convert back to drinking water values.

The 87Sr/86Sr composition of tooth enamel is derived from the average Sr isotope composition of the diet, which is closely related to the nature of the soil and underlying rocks (Ericson 1985; Sealy et al. 1991; Price et al. 1994; Sillen et al. 1998; Blum and Erel 1997; Evans and Tatham 2004). Unlike the oxygen and the light stable isotopes, there is no measurable metabolic fractionation reported for strontium isotopes. Young, low-rubidium rocks tend to generate low 87Sr/86Sr values around 0.706 in the biosphere, while older and/or more rubidium-rich rocks give higher values up to and above 0.72 (Åberg 1995). To date, values between 0.7066 and 0.7144 have been recorded in archaeological human tooth enamel in Britain (Montgomery 2002).

By combining oxygen isotope data on climate zones with 87Sr/86Sr isotope data that, through the geology, relates to geographical origins, it is possible to place constraints on the geographical origins of individuals. The results of strontium and oxygen analysis on the individuals from the three graves at Boscombe Down, Normanton Down and Stonehenge are documented in Table 1.

Table 1. Strontium 87Sr/86Sr ratios and concentration data, and oxygen isotope values for the seven individuals from this study. All oxygen data are relative to SMOW (standard mean ocean water)
SampleDentitionSr (ppm)87Sr/86Srδ18Ophosphate
Boscombe Down Adults: early childhood (Boscombe Bowmen)
BD-A1RP2 48.980.71343617.46
BD-A3LP2 76.650.71309316.91
BD-A2RP2 39.780.71351917.54
Boscombe Down adults: early adolescence (Boscombe Bowmen)
BD-A1RM3 58.910.71143317.3
BD-A3RM3 85.70.71174317.04
BD-A2RM3 45.190.71187117.39
Boscombe Down children: early childhood
BD-J1LP2 55.140.70972417.69
BD-J2RP2 54.670.70982517.61
Boscombe Down burial environment (dentine analysis)
BD-A1RM3183.650.707765 
Normanton Down and Stonehenge adults: early childhood
ND-A1LP2 37.850.70783717.78
SD-A1LP2 51.720.70822617.63
Normanton Down and Stonehenge Adults: early adolescence
ND-A1LM3 50.450.70804217.53
SH-A1LM3 44.160.7079117.46

METHODOLOGY

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

Strontium isotope analysis

The entire crown surface of the tooth was abraded to a depth of >100 µm using a tungsten carbide dental bur. Thin enamel slices were then cut from the tooth using a flexible diamond-coated dental saw. All sawn surfaces were mechanically cleaned with a tungsten carbide burr, and any adhering dentine was also removed. The resulting core enamel samples were then transferred to a clean (class 100, laminar flow) working area for further preparation.

In a clean laboratory, the enamel samples were first cleaned ultrasonically in high-purity water to remove dust, rinsed twice, washed in high-purity acetone, dried and then weighed into pre-cleaned Teflon beakers. Each sample was mixed with 84Sr tracer solution and the tooth sample was dissolved in Teflon-distilled 16M HNO3. Strontium was collected using conventional Dowex© resin ion exchange methods. The Sr isotope composition and concentrations were determined using a Triton multi-collector mass spectrometer, with a TaF emission enhancer (Birck 1986) on single rhenium filaments. All samples were run to an internal precision of ± 0.000007 (1 SE) or better. The international standard for 87Sr/86Sr, NBS987, gave values of 0.710237 ± 5 (2σ, n= 2). All strontium ratios have been corrected to an accepted value for the standard of 0.710240; Sr blanks are ∼100 pg.

Oxygen isotope analysis

The sample enamel was converted to silver phosphate (Ag3PO4) on the basis of the method described by O’Neil et al. (1994). The oxygen isotopes were analysed by continuous flow isotope ratio mass spectrometry (CFIRMS) similar to the method of Venneman et al. (2002). The instrumentation is comprised of a TC/EA (Temperature Conversion Elemental Analyser) coupled to a Delta Plus XL isotope ratio mass spectrometer via a ConFlo III interface (all manufactured by Thermo Finnigan). The reference material NBS120C calibrated against certified reference material NBS127 has an expected value of 21.70. Each sample was analysed in triplicate. The mass spectrometer reproducibility measured for this analytical batch was ±0.13 (1σ, n= 3). The external reproducibility, monitored by an ‘in-house’ reference material, was 0.15 (1σ, n= 3). The results of the oxygen and strontium analyses are presented in Table 1 and displayed graphically in Figures 2 and 3.

image

Figure 2. A comparison of the 87Sr/86Sr isotope composition of tooth enamel from burials near Stonehenge.

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Figure 3. A comparison of δ18O values from this study and those for other historical British populations. Sample BD-A3 is shown separately with an open symbol.

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RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

Strontium isotope results

The data from the adult individuals, from whom two teeth were analysed (Fig. 2), can be split into two groups—sedentary and migratory—on the basis of the strontium results. The two single burials (Normanton Down and Stonehenge) do not show a significant difference in their premolar and third molar teeth in strontium isotope composition, and hence appear to have remained within a single strontium isotope domain throughout their childhood. In contrast, the adults from the Boscombe Down burial show a significant difference in 87Sr/86Sr isotope composition between their premolar and third molar teeth, reflecting a change in environment between the formation of these two teeth. The children, for whom there is only one data point, cannot be classified by this method.

The two sedentary individuals from Normanton Down and Stonehenge  The tooth enamel from the two single burials (ND-A1 and SD-A1) (Fig. 2) has low strontium isotope compositions (0.7080–0.7082) for both their premolars and third molars, which suggests that they were static within the landscape during their childhood. Such values are entirely consistent with a childhood spent in an area dominated by Chalk, the base geology of the Stonehenge region (McArthur et al. 2001). The strontium isotope data for the adult males from Normanton Down and Stonehenge are consistent with both individuals having been born and raised around the Stonehenge area.

Evidence for the migratory nature of the adult males from the Boscombe burial  The three adult males from the collective burial at Boscombe Down provide the best evidence for human childhood migration yet seen in strontium isotope studies (Fig. 2). In all three cases, the premolars of adults suggest that they were raised in an area with an average biosphere value of ∼0.713–0.7135 and that they acquired this signature between the ages of 3 and 6 years. The males each moved locality after this age and by early adolescence (9–13 years) they all record a significantly lower average 87Sr/86Sr intake value of around 0.7116 in their third molar teeth. As the individuals were buried near Stonehenge on the Chalk, it is assumed that they travelled, at some point in their life, from their place of childhood domicile to what is now Wiltshire.

The migration to the Stonehenge area appears to have taken place after the formation of all tooth enamel, as there is no evidence that the Chalk environment is recorded in their tooth enamel compositions. Chalk will generate much lower biosphere values of around 0.708, such as are seen in the two men buried at Normanton Down and Stonehenge. The biosphere values from around Stonehenge are further confirmed by the 87Sr/86Sr isotope composition of dentine from individual BD-A1. Unlike enamel, dentine reacts with the burial environment and records the composition of burial fluids within the grave. In this case, it gives a good estimate for the local Chalk value of 0.7077, and the elevated strontium concentration of the dentine (183 ppm versus 49 ppm from the associated enamel) records its interaction and the uptake of the local strontium signature (Table 1).

Evidence for childhood migration, based on differences between tooth enamel values, has been recorded in Neolithic individuals from Wiltshire (Montgomery et al. 2000). However, this is the first case of a systematic, reproducible migration pathway from several individuals. The data suggest that all three adult males followed the same migration path during their childhood, but passed along it at different times. This may reflect the length of time that the migration took; a minimum of approximately 6 years. Alternatively, it may indicate an established route and pattern of residence, with men spending their childhood near their birthplace until they were about 6 years old, and then moving—for some social or age- or work-related reason—to another area, before finally travelling to Wiltshire in later life.

The relationship between the two Boscombe Down children

The strontium concentrations and the isotope composition of the tooth enamel from the two juveniles (BD-J1 and BD-J2) from the Boscombe Down grave are almost identical (Sr = 55.1 ppm, 87Sr/86Sr = 0.7097, δ18O =−5.9; and Sr = 54.6 ppm, 87Sr/86Sr = 0.7098, δ18O =−6.1), and from this it would be reasonable to speculate that these children were raised under similar conditions. The strontium isotope results are quite different from the adults’ teeth from the same burial. As we only have one tooth analysis from each child, we cannot comment on possible movement during tooth development. It is clear, however, that the children were raised in a different, less radiogenic, environment to the adults with whom they were buried.

It is unlikely that the children were raised on the Chalk near Stonehenge as their tooth enamel 87Sr/86Sr value is significantly higher than the 87Sr/86Sr isotope composition of the two men from Normanton Down and Stonehenge who provide a good estimate for the indigenous local signature. The data from the children's tooth enamel is most closely matched by 87Sr/86Sr values from tooth enamel from Neolithic individuals buried about 48 km south of Stonehenge at Monkton Up Wimbourne, Dorset (Montgomery et al. 2000).

Oxygen isotope results

Four of the adult males (BD-A1, BD-A2, ND-1 and SD-1) show a consistent pattern of oxygen isotope data between their premolar and molar teeth (Table 1). In each case the premolar is, on average, about 0.18 more enriched in δ18O than the third molar. The cause of this is not certain, but it may be a residual effect of a pre-weaning component in the diet showing in the earlier tooth, as mother's milk is enriched over drinking water because of the metabolic fractionation in the mother's body (Wong et al. 1987).

Individual BD-A3 is unusual in having a significantly lower δ18O value and an oxygen shift between the premolar and third molar that is the opposite of the individuals described above, as his premolar has a lower δ18O than his third molar. This cannot be explained within the confines of this study. The very strong relationship between individual BD-A3 and the two adults with whom he was buried (BD-A1 and BD-A2), as reflected in the commonality of their Sr isotope signatures, and the osteological evidence that supports a common stock population, argue against an origin for this individual being in a different place, climate or culture.

The measured δ18O from this study is compared with three other historical British populations; two Anglo-Saxon populations from West Heslerton in Yorkshire (Budd et al. 2002) and Ketton in Rutland (Tatham 2004) and the ‘main group’ of a Romano-British population from the Lankhill's cemetery, at Winchester in Hampshire (Evans et al. 2006) (Fig. 3). The data show that all the individuals from this study are consistent with an origin in a British or a comparable climatic zone in Europe. The majority of the data from this study match most closely with the Romano-British data from Hampshire, which is within the −6 to −7 drinking water contours of Darling et al. (2003) (Fig. 4). This is consistent with an origin around Stonehenge for the two sedentary individuals from Normanton Down and Stonehenge Ditch, and it suggests that the rest of the individuals are also from this westerly and southerly British drinking water zone.

image

Figure 4. Drinking water contours for the UK (reproduced with permission from Darling et al. 2003), with British archaeological sites from Figure 3 superimposed.

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Where did the Boscombe Bowmen come from?

What can be said about the route that these men travelled? It is difficult to identify exactly where the adult males from the Boscombe burial came from, but some parameters can be defined. The values from their teeth are quite unusual for Britain. Montgomery (2002) documents three human enamel samples with 87Sr/86Sr above 0.711 and two with 87Sr/86Sr enamel values above 0.713 out of a study of 79 tooth enamel analyses from archaeological sites in the UK. Chalk and limestone sequences (dominated by calcium carbonate) can be ruled out as a possible childhood site, as these are typified by ‘low’ values close to the rock compositional range of 0.7069–0.7092 (McArthur et al. 2001), which covers the compositional range from a minimum during the Jurassic to present-day carbonate rocks. It is much harder to estimate the Sr isotope ratio composition of biospheric components derived from silicate rocks because of their multi-mineralic nature (Blum and Erel 1997; Sillen et al. 1998), but the main types of rock that are likely to provide a suitable site for the early childhood premolar teeth of the Boscombe adult males are granites and early Palaeozoic, or older, rocks. Such rocks can be found in Britain in Scotland (Millar 1990 and references therein), the Lake District (Evans 1996b), Wales (Evans 1989, 1996a; Shand et al. 2001) and south-west England (Darbyshire and Shepherd 1985).

Of these areas, Wales is the closest to the burial site and is an attractive option, as it has known links with Stonehenge at this time. The bluestones of Stonehenge can be provenanced very accurately by petrology and chemical analyses to a small area in the Preseli Hills in south-west Wales (Thorpe et al. 1991; Green 1997; Scourse 1997; Williams-Thorpe et al. 1997), and the date at which the stones were brought to Stonehenge compares well with the date of the Boscombe individuals (Fitzpatrick 2004). Other sites would have to be assessed on their archaeological merits.

If an origin for these individuals outside Britain is considered, then the following regions are, on geological grounds, a possibility: south-east Ireland (O’Conner et al. 1988), Brittany and the Massif Central of France (Negrel et al. 2003), the Palaeozoic rocks of Portugal (Tassinari et al. 1996) and the Black Forest (Schutkowski et al. 2000). Much of northern central France can be excluded, as it is dominated by chalk and gives river water values below 0.71 (Negrel and Petelet-Giraud 2005) and Norway and Sweden can be ruled out as they are dominated by old Proterozoic rocks that give high 87Sr/86Sr values, generally above 0.72 (Åberg 1995), and are probably too radiogenic to provide a possible homeland. Oxygen isotope data would restrict possible areas of the continent to those having δ18O drinking water compositions comparable to those of this study.

In summary, the isotope features of the three adults from the burial suggests that they spent their early childhood in an area of pre-Mesozoic or granitic rocks, within an oxygen zone similar to that of west/central Britain.

Sr concentrations as dietary indicators

Finally, it should be noted that all individuals in this study have similar strontium concentrations in their tooth enamel, giving an average result of 54 ± 14 ppm (1σ). This is comparable with other Neolithic people from Monkton Up Wimbourne (69.9 ± 17 ppm; 1σ, n= 7; Montgomery et al. 2000) and modern UK teeth (51.6 ± 16 ppm; 1σ, n= 29; unpublished data). It is lower than for native Britons of the Roman period (120 ± 58 ppm; 1σ, n= 8; Evans et al. 2006) and for coastal dwellers in the Outer Hebrides (237 ± 79 ppm; 1σ, n= 13; Montgomery et al. 2003). Strontium concentrations are observed to drop with an increasing trophic level in the diet, and by comparison with the modern diet this suggests that the Bronze Age individuals had a mixed regime, consuming meat and dairy products in proportions comparable to those of modern Britons.

CONCLUSIONS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

The beginning of the Bronze Age, as represented by these seven individuals, was a time of contrasting mobility. The individuals from Normanton Down and Stonehenge were raised within the area of Stonehenge, and as they were buried in this area it would seem reasonable to assume that they were essentially non-migratory, at least during their childhood.

The data from the adult males buried at Boscombe Down paint a very different picture. The men had moved across the land, during their childhood, from an area of radiogenic rocks to a second site before journeying to what is now Wiltshire, where they were buried, together, near Stonehenge. These people record a pattern of movement, which suggests that they each made the same journey or, rather, spent the same parts of their lives in the same places. Wales is the nearest area that can supply the appropriate 87Sr/86Sr values for the early childhood values, which means that they travelled at least 150–200 km during their lives.

The Boscombe Down juveniles, whose Sr data are so similar, did not make the same journey. They came to Stonehenge from elsewhere. Strontium concentrations suggest that all of these individuals had a diet that is comparable to the modern UK diet in terms of meat/dairy content.

ACKNOWLEDGEMENTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES

We thank Julian Richards for supplying the Stonehenge sample and the BBC for allowing us to publish the data on this sample. The Normanton Down samples were made available by Wessex Archaeology in projects commissioned by Bloor Homes, Persimmon Homes, Quinetiq and the Highways Agency. Jackie McKinley is thanked for her help with the Boscombe Down individuals, George Darling for the use of his map, and Janet Montgomery and two anonymous reviewers for their constructive comments. NIGL publication no. 287.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. ARCHAEOLOGICAL DESCRIPTION
  5. THE AIM OF THE STUDY
  6. THE CHOICE OF TEETH
  7. MIGRATION STUDIES
  8. THE APPLICATION OF STRONTIUM AND OXYGEN ISOTOPES IN ARCHAEOLOGICAL STUDIES
  9. METHODOLOGY
  10. RESULTS
  11. CONCLUSIONS
  12. ACKNOWLEDGEMENTS
  13. REFERENCES
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