A strontium and oxygen isotope assessment of a possible fourth century immigrant population in a Hampshire cemetery, southern England Jane Evans a , Nick Stoodley b, * , Carolyn Chenery a a NERC Isotope geosciences Laboratory, Keyworth, Notts NG12 5GG, UK b Department of Archaeology, University Park, University of Nottingham, Nottingham NG7 2RD, UK Received 4 May 2004; received in revised form 29 June 2005; accepted 21 July 2005 Abstract The aim of the project was to test the hypothesis, using oxygen and strontium isotopes, that a group of burials in the Late Roman cemetery of Lankhills, Winchester, southern England, were migrants from the Danube region of central Europe. The method as- sumes that the oxygen isotope composition of immigrants from this locale would be significantly more depleted that any one British origin and that the restricted range in Sr isotope compositions produced by chalk in the overlying biosphere of southern England would discriminate between the local population and settlers from elsewhere. As a control for the immigrant group a sample of Romano-British individuals were examined to provide a comparative data set. The results showed that the majority of the individ- uals used to define the ‘‘local’’ control group plotted in a restricted field of strontium and oxygen isotope composition that was con- sistent with the values expected for the Hampshire area of southern England. By contrast, the ‘‘exotic’’, putatively immigrant population generated a much more dispersed field including four with d 18 O drinking water values of ÿ10& or less, which supports a non-British origin for these individuals. The study shows that the archaeological data suggesting that there is an exotic population buried at the Lankhills cemetery is generally supported by the isotope work, although the ‘‘exotic’’ group appears to a rather dis- persed set of individuals rather than a single population from a restricted overseas location. Ó 2005 Published by Elsevier Ltd. Keywords: Oxygen isotopes; Strontium isotopes; Migration; Burial ritual; Lankhills 1. Introduction Strontium and oxygen isotopes are increasingly used to assess human populations with respect to their struc- ture and diversity and this is done in a number of ways. The first method is to make a statistical assessment of the individuals within a group in order to understand the population dynamics: are there outliers, bimodality or relationships between compositions and status/gender. The second approach is to relate isotope measurements to external measurements of climatic zone (oxygen isotopes) and biosphere compositions (strontium iso- topes) in order to assess the relationship of the individu- als to the area in which they where buried. This latter option is harder as it requires a good understanding of climatic zonation and biosphere variations within the areas of interest. However, it is possible to comment on the origins of individuals especially when tested against special claims from the archaeological record. At the Lankhills cemetery in Hampshire such an opportunity exists as, within the site, there is a group of individuals whose burial rites are clearly unique, different from the local population within the cemetery (Romano-British) and, tantalisingly, have, after extensive archaeological research, been assigned an origin in central Europe [5]. * Corresponding author. E-mail address: [email protected](N. Stoodley). 0305-4403/$ - see front matter Ó 2005 Published by Elsevier Ltd. doi:10.1016/j.jas.2005.07.011 Journal of Archaeological Science 33 (2006) 265e272 http://www.elsevier.com/locate/jas
Transcript
Journal of Archaeological Science 33 (2006) 265e272
http://www.elsevier.com/locate/jas
A strontium and oxygen isotope assessment of a possiblefourth century immigrant population in a Hampshire
cemetery, southern England
Jane Evans a, Nick Stoodley b,*, Carolyn Chenery a
a NERC Isotope geosciences Laboratory, Keyworth, Notts NG12 5GG, UKb Department of Archaeology, University Park, University of Nottingham, Nottingham NG7 2RD, UK
Received 4 May 2004; received in revised form 29 June 2005; accepted 21 July 2005
Abstract
The aim of the project was to test the hypothesis, using oxygen and strontium isotopes, that a group of burials in the Late Romancemetery of Lankhills, Winchester, southern England, were migrants from the Danube region of central Europe. The method as-sumes that the oxygen isotope composition of immigrants from this locale would be significantly more depleted that any one British
origin and that the restricted range in Sr isotope compositions produced by chalk in the overlying biosphere of southern Englandwould discriminate between the local population and settlers from elsewhere. As a control for the immigrant group a sample ofRomano-British individuals were examined to provide a comparative data set. The results showed that the majority of the individ-
uals used to define the ‘‘local’’ control group plotted in a restricted field of strontium and oxygen isotope composition that was con-sistent with the values expected for the Hampshire area of southern England. By contrast, the ‘‘exotic’’, putatively immigrantpopulation generated a much more dispersed field including four with d18O drinking water values of �10& or less, which supports
a non-British origin for these individuals. The study shows that the archaeological data suggesting that there is an exotic populationburied at the Lankhills cemetery is generally supported by the isotope work, although the ‘‘exotic’’ group appears to a rather dis-persed set of individuals rather than a single population from a restricted overseas location.� 2005 Published by Elsevier Ltd.
Strontium and oxygen isotopes are increasingly usedto assess human populations with respect to their struc-ture and diversity and this is done in a number of ways.The first method is to make a statistical assessment of theindividuals within a group in order to understand thepopulation dynamics: are there outliers, bimodality orrelationships between compositions and status/gender.The second approach is to relate isotope measurementsto external measurements of climatic zone (oxygen
0305-4403/$ - see front matter � 2005 Published by Elsevier Ltd.
doi:10.1016/j.jas.2005.07.011
isotopes) and biosphere compositions (strontium iso-topes) in order to assess the relationship of the individu-als to the area in which they where buried. This latteroption is harder as it requires a good understanding ofclimatic zonation and biosphere variations within theareas of interest. However, it is possible to comment onthe origins of individuals especially when tested againstspecial claims from the archaeological record. At theLankhills cemetery in Hampshire such an opportunityexists as, within the site, there is a group of individualswhose burial rites are clearly unique, different from thelocal population within the cemetery (Romano-British)and, tantalisingly, have, after extensive archaeologicalresearch, been assigned an origin in central Europe [5].
266 J. Evans et al. / Journal of Archaeological Science 33 (2006) 265e272
In this paper we therefore use strontium and oxygenisotopes to test the hypothesis that individuals buriedwith unique burial rites, at Winchester’s (Hants) lateRoman cemetery of Lankhills were a mixed-sex immi-grant population raised in the Hungarian basin whohad travelled to southern Britain during the second halfof the fourth century AD, with the Roman army, possi-bly following an event which saw the depopulation oftheir homelands [5].
2. Application of Sr and O isotopes in
archaeological studies
Oxygen isotope composition of bio-phosphate can bedirectly related to that of ingested (drinking) water usingphosphate oxygen e drinking water equations such asthat of Levinson et al. [12] that take into account meta-bolic fractionation. The calculated drinking water valuecan be compared against well-documented modern oxy-gen isotopes zones across the UK [6] and, to a less well-constrained level, into continental Europe [11].
The modern day range of measured groundwater inthe UK is between �4 and �9 [6]. This is likely to bea reasonable estimate of the UK range of values into his-torical times as it is based on aquifer samples that aretens to hundreds of years old [6]. Pollen based palaeocli-mate studies suggest that the climate in west centralEurope has remained essentially stable for the last 5000[7] and such observations are supported by direct mea-surements from 5200 BP tooth enamel from a humanmummy (the Iceman) and from speleotherm data fromthe Alps [16].
Although it is possible to subdivide direct measure-ments of drinking water in UK into clearly defined zones[6], it is not known how distinctive and restricted in val-ues the drinking water values calculated from humantooth enamel are likely to be. Archaeological studiesprovide some evidence for the range of values expectedwithin a population. The drinking water data from theAnglo-Saxon population of west Hesleton in Yorkshiregive d18OdwZ�7.76G 2.76& (2s, nZ 24) for the com-munity [3]. The site at West Hesleton may containa mixed population increasing the diversity of the dataset, however, a study on static rural Anglo-Saxon com-munities at Ketton and Empingham in central Englandgave similar values of KettonZG2.9& (2s, nZ 25)and EmpinghamZ 2.8& (2s, nZ 17) [25,26]. Usinga figure of 2.8& (2s) as a reasonable estimate of localpopulation diversity, and the mid range value forgroundwater in the Winchester area of �6.5&, it seemlikely that a community living around Winchester undersimilar climatic conditions to modern times would bedefined as d18OdwZ�6.5G 2.8& (2s).
The 87Sr/86Sr composition of tooth enamel is derivedfrom the average Sr isotope composition of the diet,
which is closely related to the nature of the soil and un-derlying rocks [1,2,8,9,18,23]. Young, low rubidiumrocks tend to generate low 87Sr/86Sr values around 0.706in the biosphere, while older and/or more rubidiumrich rocks give higher values, ca. 0.715. To date, valuesbetween 0.7066 and 0.7144 have been recorded in ar-chaeological human tooth enamel in Britain [15].
3. Approach to the problem of defining
the local Sr conditions
The area of southern England, around Winchester,where the Lankhills cemetery is located, is dominatedby chalk with Oligocene and Eocene sands, clays andlimestone. Direct measurements of the composition ofthe overlying biosphere in this area are not available,however, two methods are used to constrain the rangeof 87Sr/86Sr values found in the region of interest. A firstapproximation is that the values will range between thecompositions of chalk (0.7072) [13] and rainwater(0.7092) but because this is a rather poorly constrainedestimate, a second approach was used: to analyse thetooth enamel of individuals from the area who are inter-preted as of local origin. This approach has advantagesand disadvantages; in its favour, it means that the pop-ulation statistics, in terms of diversity and range, can bedirectly compared with another human population. Thedisadvantage it that we are dependant upon archaeolog-ical evidence for defining a ‘‘local’’ population.
By combining oxygen isotope data on climate zoneswith 87Sr/86Sr isotope data that through the geology re-lates to geographic origins for both the exotic and con-trol population, we aim to test the hypothesis for theorigins of the exotic group outlined above.
4. Description of site and archaeology
The late Roman cemetery of Lankhills is locatedwithin the modern city of Winchester in Hampshire,southern England (Fig. 1). It was excavated during1967e1972 by Clarke [5] and is one of several large burialgrounds that surrounded Roman Winchester, VentaBelgarum. The vast majority of the interments followedburial customs that are probably to be viewed as reflect-ing a religious adherence which was essentially pagan:the paraphernalia associated with provisioning for thejourney to the afterlife, e.g. vessels containing drink,food offerings, footwear and coins to afford passageacross the Styx; though for a more cautious discussion,see Salway [21]. Lankhills is notable because of the con-tinuance of these customs right up until the abandon-ment of the cemetery at some point in the early fifthcentury, while in contemporary cemeteries accompaniedburial was being phased out, e.g. Poundbury, Dorchester,
267J. Evans et al. / Journal of Archaeological Science 33 (2006) 265e272
Dorset [10] e an act which possibly took place underthe influence of Christianity [20,27]. Within the ceme-tery is a group of individuals that do not conform tothe predominant modes and rituals of burial at the siteand these have been suggested to be an exotic on immi-grant population [5].
5. A comparison of the burial details of the two groups
The suggestion of an exotic population, thought to beforeign migrants, within the burial ground at Lankhillswas based on the distinctively different nature of theirburials [5]. The group comprises 16 individuals fromthe second half of the fourth century. They are notedfor their uniformity of burial ritual and its significantdifference from the much larger corpus of burialsbelonging to the native Romano-Britons interred inLankhills. The differences are summarised below andpresented in Table 1.
The purported migrant group is characterised by therelatively large quantities of objects deposited with thedead. Furthermore, these objects comprised artefactsthat could be grouped according to several different cat-egories: personal ornaments (mainly jewellery), vesselsand items of personal equipment. A key defining featurewas the remarkable consistency in the position of theobjects in relation to the body, especially the strict reg-ularity demonstrated in the positioning of the personalornaments, many of which were actually adorning thedeceased. This is especially apparent for the female bur-ials. Other diagnostic features include a tendency for
Lankhills
Pannonia
Vienna
Belgrade
Fig. 1. A sketch map of parts of Europe showing the location of
Roman Pannonia and the Lankhills cemetery.
vessels and other types of offerings to be placed closeto the right foot and for a lack of practices usually asso-ciated with native burials, i.e. the placing of coins in themouth or hand and the deposition of hobnailed foot-wear in the grave.
The corpus of native burials does demonstrate cleardifferences in terms of artefact numbers and types, andtheir positioning in relation to the deceased. The major-ity of burials were not accompanied with any type of ob-ject. When objects are present they are usually restrictedto single items or small collections of artefacts. What isimportant to understand is that the practice of furnish-ing these burials does not appear to have any obviousstructure to it. Objects of the same type are not repeat-edly found in combination nor are their position withinthe grave characterised by any uniformity. This is clearlyshown by the jewellery in the native burials, which insharp contrast to ‘‘exotic’’ group, were not worn at thetime of burial, especially the bracelets, but were placedas a separate offering alongside or over the body. Thisconforms to late Roman burial practice in Britain gener-ally and is taken to indicate that the individual was notclothed at burial, but was interred in a shroud or gown.Other practices that are indicative of late Roman burialin Britain include the well-known practices of placinga coin about the deceased to afford passage to the Oth-erworld and the habit of including hobnails in the grave.The majority of individuals at Lankhills demonstrateone or more of these traits.
6. Details of the ‘‘exotic’’ group
The group of nine individuals are a mixed sex andmixed age group (Table 2). Two of the individuals areconfirmed as males (13 and 322), and two are probablymales on the basis that the objects found with them areassociated with soldiers (81 and 426). The remaining fiveindividuals (326, 351, 63, 333, and 323) have objectswith their graves that would be associated with females,such as beads and necklaces. This group includes two ju-veniles (333 and 323). The range in ages is from the old-est individual, an adult male of 45C years, to three adult
Table 1
Description of the principle differences in burial type used to define the
‘‘local’’ and ‘‘exotic’’ populations [5]
‘‘Exotic’’ group Control group
Numerous artefacts Artefacts are scarce
Numerous artefact types Restricted artefact types
Personal ornaments
worn at burial
Personal ornaments not worn
Vessels and animal offerings
by right foot
Vessels and animal offerings
in area of feet
Coins (but not in mouth) Coins placed in mouth/hand
The designation of sex (M? and F?) is based on the nature of the accompanying grave goods.
males between 25 and 35 years old. The (probable)women include a ca. 25 years old, two unassigned agesand the juveniles are 3.5 and 5e6 years old.
7. Suggested origins for the ‘‘exotic’’ group
The exotic group are suggested to be of Samartianorigin from the area of Hungary, east of the Danube,known in Roman times as Pannonia (Fig. 1). Theymay have travelled to southern Britain during the sec-ond half of the fourth century AD with the Romanarmy, possibly following an event which saw thedepopulation of their homelands [5]. This suggestionhas found recent support by Swift [24] who demon-strates that some of the objects accompanying theseindividuals have their closest parallels in modern dayHungary, such as the buckle and plate in grave 234,which is of a type mainly found in Pannonia and Dalma-tia. Hexagonal blue cylinder beads, as found in graves323 and 336, are predominantly found along the Romanfrontier on the Upper Danube [24] and the practice ofwearing bracelets finds a parallel in some Pannonianburial grounds. The manner in which the bracelets areworn on each arm closely matches the custom in theDanube region: copper alloy bracelets are only foundon the right wrist, while bracelets of various materialscould be combined on the left one. Moreover, this is arite with an age-related dimension to it: younger womenand girls have greater quantities of bracelets and theseare confined to the left wrist, while older women woreone or two on the left wrist and occasionally one on therighte this distinction is also replicated at Lankhills [24].
8. Isotope characteristics of south central Europe
The area of Roman Pannonia is bordered to thenorth and east by the Danube, northern Italy to the westand has a border to the south with the Dalmatian coast(see Fig. 1). Geologically, the area is dominated bya thick sequence of Neogene-Quaternary sediments,
which comprise turbidites, deltas, shallow lake andbraided river deposits carrying debris from the erosionof the Alps [14]. The best estimate biosphere valueswithin this area is provided by a recently published sum-mary of tooth enamel analysis from Beaker People insouthern Europe (Germany, Austria, Czech Republicand Hungary) by Price et al. [19]. The 87Sr/86Sr of 81individuals gives a mean value of 0.7097G 0.0026 (2s,nZ 81).
In terms of climate, the oxygen isotope compositionof drinking water in the area of Pannonia (central Eu-rope) has significantly more depleted d18O drinking wa-ter than Britain and hence could provide an importantdiscriminant in this study. Values are likely to be lowerthan d18OdwZ�9.0& on the basis of Lecolle [11] andcould be even more depleted in mountainous areas.
In summary, the area of Roman Pannonia shouldhave a more depleted (more negative) d18O groundwatersignature than the British Isles making oxygen isotopesa potentially good discriminant. 87Sr/86Sr values forPannonia are predicted to be within the range of0.7097G 0.0026 (2s) which is slightly higher than thevalues predicted for the local British environment.
9. Methodology
9.1. Sr analysis
The tooth enamel was cleaned ultrasonically for5 min in high purity water and rinsed twice to removeloosely adhered material. The entire crown surface hadbeen abraded from the surface to a depth of O100 mmusing a tungsten carbide dental bur and the removedmaterial discarded. Thin enamel slices were then cutfrom the tooth using a flexible diamond edged rotarydental saw. All saw surfaces were mechanically cleanedwith tungsten carbide bur, and any adhering dentinewas also removed. The resulting core enamel sampleswere then provided to staff at NIGL, sealed in cleancontainers where they were transferred to a clean (class100, laminar flow) working area for further preparation.
269J. Evans et al. / Journal of Archaeological Science 33 (2006) 265e272
In a clean laboratory, the enamel sample were firstcleaned ultrasonically in high purity water to removedust, rinsed twice, dried down in high purity acetoneand the weighed into pre-cleaned Teflon beakers. Aknown amount of 84Sr tracer solution was added to eachsample which was dissolved in Teflon distilled 16 MHNO3. The sample was converted to chloride usingQuartz distilled in 6 M HCl and then taken up in2.5 M HCl. The Sr was extracted using conventionalion exchange methods.
Sr isotope composition and concentrations were de-termined using a 262 Finnigan mat Multicollector massspectrometer which typically gave a value of 0.710285G27 (nZ 5, 2s), for the international standard for87Sr/86Sr, NBS987. There was some drift during the pe-riod of analysis so all strontium ratios have been correctto an accepted value for the standard of 0.710240.Sr blanks are !100 pg.
10. Oxygen isotopes
The prepared enamel samples were converted to sil-ver phosphate using the method of O’Neil et al. [17]and is briefly summarised here with further detail avail-able in Chenery [4]. The samples were crushed to a finepowder and cleaned in hydrogen peroxide for 24 h to re-move organic material. The peroxide was evaporated todryness and the sample dissolved in 2 M HNO3. The
sample solutions were transferred to clean polypropyl-ene test tubes and each sample was treated with 2 MKOH followed by 2 M HF to remove Ca from the solu-tion by precipitation. The samples were centrifuged andthe solution was added to beakers containing ammonia-cal silver nitrate solution and heated gently to precipitatesilver phosphate. The silver phosphate was filtered,rinsed, dried andweighed into silver capsules for analysis.Oxygen isotopemeasurements on each sample weremadein triplicate by thermal conversion continuous flow iso-tope ratio mass spectrometry (TC/EA-CFIRMS) usingthe method of Vennemann et al. [28]. NBS 120C gavea value of 21.56G 0.5& nZ 5, during this study. Dataare corrected to a value of 21.7& which is the acceptedNIGL value for this standard: NBS 120CZ 21.7G0.7&, 2 SD, nZ 81, analysis over a 6-month period,calibrated against certified reference material NBS127.Details in Chenery [4]. The external precision of the oxy-gen analysis, based on the analysis of in-house stan-dard ACC1 (commercial hydroxy-apatite converted toAg3PO4) was G0.3& (2s). All the data are presentedin Table 3.
11. Results
The results of the O and Sr isotope analyses are plot-ted in Fig. 2. The oxygen data are given as drinkingwater values calculated using Levinson et al. [12]
Table 3
The 87Sr/86Sr data measured d18O and calculated drinking water values using Levinson for the two populations at Lankhills, Hampshire
Sample number Tooth Sr (ppm) 87Sr/86Sr d18OSMOW G1 SD d18Odw
270 J. Evans et al. / Journal of Archaeological Science 33 (2006) 265e272
-14.0
-12.0
-10.0
-8.0
-6.0
-4.0
-2.0
0.706 0.707 0.708 0.709 0.710 0.711 0.712
The “exotic” individualsIndividuals taken to define the local signature
δ180 range from Anglo Saxons (northern England)
Probable range of δ18O values for Anglo Saxonsin southern England
87Sr/
86Sr ratio
δ18O
d
rin
kin
g w
ater
The main field
“Exotic group” deciduous teeth
Modern individuals from the Alps (Muller et al 2003.)
X
X
Lower limit of average British
δ18O drinking water composition.
Fig. 2. d18O plotted against 87Sr/86Sr isotope composition for tooth enamel from individuals from the Lankhills burial site. Data from central Eng-
land are from Budd et al. (2003). The ‘expected range for southern England’ is constructed using the central value for the area e 6.5 based on Darling
(2003) with 2.8& (2s) error which is currently the best estimate for variation in static UK population [25]. Data from modern continental individuals
[16] have been recalculated using Levinson et al. [12] and give d18O Z �11.5G 2.6& (2s, nZ 18).
calibration. There is a clear contrast between the controland exotic groups of data. The majority of the controlgroup defines a restricted field within d18Odw vs 87Sr/86Srspace within the range of predicted values for southernEngland whereas the ‘‘exotic’’ population generatesa dispersed field with a wide range of both d18Odw and87Sr/86Sr values. From the dispersed nature of the datafrom the ‘‘exotic’’ population, it can be concluded thatthese people are not local to southern Britain and thatif all these individuals are immigrants they cannotrepresent a group of people from a single localisedcommunity.
12. Discussion
12.1. The main control group
The data from the control groups of individuals de-fined as Romano-British, and taken to be raised nearthe burial site in Hampshire, form a cluster of data thatappears to support this assumption. Seven of the nineresults give an average value of 87Sr/86SrZ 0.7085G0.0004 (2s, nZ 7), and drinking water oxygen valuesof d18OdwZ�6.7G 2.0& (2s, nZ 7). These are veryclose to the predicted values for this part of Hampshireand provide a good control set of data against which tocompare the putative Pannonians. Two of the controlgroups plot apart from the main group (55 and 357).These two individuals are classified, on their burial rites,as Romano-British, and are not part of the ‘‘exotic’’group [5], however, their oxygen isotope composition
(d18OdwZ�9.61&, �9.92&) is too depleted to be fromsouthern Britain and suggests that they are of continen-tal origin although not from the culturally ‘‘exotic’’group defined as ‘‘intrusive’’ by Clarke [5].
12.2. The ‘‘exotic’’ group
This exotic population shows a very wide range ofoxygen and strontium isotope compositions which sup-port the argument that they are not, predominantly,from the southern Britain, but equally, it is unlikelythat, with such diverse data, that they are from a singlepopulation. Four of the samples, three males (81, 426,and 13) and one ?female (351), have continental oxygenisotope drinking water values (d18OdwZ�13.2&,�12.38&, �10.8& and �10.4&) that exclude a child-hood in Britain and are consistent with a childhood incontinental Europe. The most negative values withinthis group could indicate an upbringing in mountainousregions as drinking water becomes more depleted withaltitude. They compare well with data from the 3rdmolarof modern individuals from the area of the Italian/Austrian Alps who have values1 of d18OdwZ�11.5G2.6& (2s, nZ 18) [16]. Within this group three individ-uals (81, 426, and 351) have 87Sr/86Sr values of 0.7093.0.7094 and 0.7090, respectively, within a range pre-dicted for southern central Europe (0.7097G 0.0026,2s, nZ 81) on the basis of Bell Beaker data [19].
1 Values given by Muller et al. [16] have been recalculated using
Levinson et al. [12] calibration to make them comparable with data
271J. Evans et al. / Journal of Archaeological Science 33 (2006) 265e272
One individual (13) has a low 87Sr/86Sr ratio of 0.7064with an elevated Sr concentration of 255 ppm. Suchdata are consistent with a childhood spend in an areaof young un-radiogenic rocks. Such rocks can be foundin several areas in Europe including parts of Hungarywhere Quaternary and younger volcanic rocks give anaverage 87Sr/86Sr value of 0.7066G 0.004, (2s, nZ 19)[22]. The oxygen isotope data from these four individualsexclude them from a British origin and the strontiumisotopes suggest that three may have come from a similararea but that one, 13, probably comes from an area ofyoung volcanic rocks within central southern Europe.
A further four of the ‘‘exotic’’ group are within thefield of ‘‘locals’’ (two adult ?females, 66, 326, and two ju-veniles, 323 & 333). These four individuals all have Sr 87/Sr86 isotope values within the field of the ‘‘local’’ group.The two adults plot within this field in terms of oxygenisotope composition. The oxygen isotope data from thejuvenile’s teeth are the least depleted in this study(d18OdwZ�4.2& and �4.4&), however, this is an arte-fact of having analysed deciduous teeth from these chil-dren. Teeth that form before weaning are influenced bythe composition of the mothers milk, which is enrichedin d18O relative to the drinking water she consumes[29]. Hence, the oxygen data from the deciduous teethof these two juveniles cannot be compared directly withthe data from permanent teeth, but it is likely that with-out the metabolic pre-weaning effects their tooth enamelwould plot within the field of locals. The isotope data donot, therefore, show that these are immigrant, they sup-port an upbringing in southern England, however, whencombined with ritual evidence from the burials it is mostlikely that they are second-generation immigrants re-vealing their birthplace through their isotope composi-tion but retaining all the cultural behaviour of theirupbringing. This is particularly likely for juveniles whoare perhaps, less likely than the adults to have madea journey from Southern Europe.
The last obvious outlier is the 25C-year-old male(322) which has a drinking water oxygen value ofd18OdwZ�7.63G 0.16& (1s) and a strontium valueof 0.7116. The oxygen value is within the range of UKvalues and is typical of much of Britain and parts ofHolland, France and west Germany. The Sr isotope sig-nature is too high for someone raised on a chalk. It isdifficult to say more than that he is probably from anarea of western Europe that is not founded on a chalk/limestone-dominated substrate.
Finally, it is noted that the two ‘‘local’’ Romano-Britons, who fall outside the ‘‘main group’’ of composi-tion, plot very close to the immigrant ?female 315 and allthree could reasonably be said to form a cluster. Wecannot provide any explanation for this beyond the pos-sibility that these two individuals could be from thesame continental region as 351 but were buried usingRomano-British customs.
13. Conclusions
This study aimed to compare the origins of two cul-turally distinct populations, both represented withinthe Lankhills burial ground, using the isotope composi-tion of tooth enamel to determine the geological/geo-graphic and climatological childhood environments ofboth populations. The two populations, one Romano-British and believed to be indigenous, and one exoticand believed to be from the Hungarian region of Europe[5], did not, on the basis of strontium and oxygen iso-topes, fall into two clearly separate groups, suggestingthat our starting assumptions about origin were oversimplified. However, several important conclusions canbe derived from the study.
The population diversity of the two groups differs. Theindigenous group of Romano-Britons predominantlyforms a cluster of data, which can reasonably be takento represent the realistic extent of variation in a staticpopulation. The range of Sr isotopes values is consistentwith biosphere values on a chalk-based substrate and thecalculated drinking water oxygen isotope values are con-sistent with modern day data from southern England. Incontrast, the population defined as ‘‘exotic’’, on the basisof burial customs, shows a much greater diversity in iso-tope data. This supports a non-indigenous origin for atleast some members of this group of people but doesnot support the suggestion that these people were fromthe same place of origin in southern Europe.
Oxygen and strontium isotopes have provided sup-port for the ritual based subdivision of these two burialgroups but have provided new evidence about the diver-sity of the population in Winchester during this period.Such studies provide valuable insights into human diver-sity, which can be compared and contrasted with thecultural diversity represented by grave goods and histor-ical data.
Acknowledgements
We thank Winchester Museums Service and TheWinchester Research Unit for access to skeletal materialand Prof. J. Henderson D. Poore Annie Bingham, andEllen Swift for discussion and access to data.
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