Mobility of Bell Beaker People Revealed by Strontium Isotope Ratios of Tooth and Bone: a Study of Southern Bavarian Skeletal Remains

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Mobility of Bell Beaker people revealed by strontium isotope ratios of tooth and bone: a study of southern Bavarian skeletal remains

Gisela Grupe Institut fur Anthropologic und Humangenetik, Richard-Wagner-StraBe 10, Munich D-80333, Germany

T. Douglas Price Department of Anthropology, 1180 Observatory Drive, University of Wisconsin, Madison, WI 53706-I 393, U.S.A.

Peter Schriiter Anthropologische Staatssammlung, Karolinenplatz 2a, Munich D-80333, Germany

Frank Siillner Institut fur Allgemeine und Angewandte Geologie, LuisenstraDe 37, Munich D-80333, Germany

and

Clark M. Johnson and Brian L. Beard Department of Geology and Geophysics, 1215 W. Dayton St., Madison, WI 53706-1393, U.S.A.

(Received 1 August 1996; accepted in revisedform 29 January 1997)

Abstract-In order to contribute to the continuing discussion of the mobility of the late neolithic Bell Beaker people, 69 skeletons from southern Bavaria were analyzed for the 87Sr/86Srisotope ratios in tooth enamel and compact bone. Whereas Sr isotope ratios in the enamel of the first permanent molar match the Sr isotopic composition at the place of early childhood, the respective value in the adult femoral bone matches the Sr isotope ratio characteristic of the place of residence over the last few years prior to death. Significant differences between *‘Sr/*?Sr in these tissues indicate that 17.525% of these individuals changed residence during their lifetime. The overall direction of the migration, according to archaeological finds from the area, was toward the southwest. A relative surplus of migrating females and two cases ofevidence for migration in children argue for the movement of small groups; exogamy might explain the higher numbers of immigrating females. With regard to current information on migration rates in prehistory, the southern Bavarian Bell Beaker people were indeed highly mobile, especially since the archaeometric method used in this study is likely to underestimate movement. 0 1997 Elsevier Science Ltd

INTRODUCTION River, followed by a split into 3 “regional groups”: the southern Bell Beaker with finds from Spain, Portugal, Bell Beaker and residential mobility southern France and Italy; the western Bell Beaker with sites in central and northern France, Great During the earlier Neolithic, central Europe was Britain and Ireland, the Benelux countries, the Rhine divided into a variety of regional cultures. Prestige region, and the north German lowlands; and finally objects, made of Cu and other materials, were the eastern group in Hungary, the Czech Republic and distributed by trade; thus, the existence of specialized Slovakia, Austria, and southern Bavaria. craftsmen by the late Neolithic is assumed (De Laet, Human skeletal materials associated with Bell 1994; Lfining, 1994). In the course of only a few Beaker artifacts are morphologically distinct from centuries between 2500 and 2000 B.C. at the end of the those of the indigenous people of the earlier Neolithic Neolithic, Bell Beaker pottery, and presumably and exhibit a new, short-headed “morphotype” people, spread over large parts of Europe, from (Gerhardt, 1978). In addition, there were very few Portugal and Ireland to Hungary and from Scotland known settlement sites or house structures from the to Sicily and North Africa. period. The widely distributed Bell Beaker pottery, the It is difficult to characterize the Bell Beaker as a absence of settlement, and the new physical type, thus culture in the formal sense. Particularly during the required explanation and generated much speculation early part of the period, there is an absence of (Sangmeister, 1972). The Bell Beaker people, for common house types, burial customs, or even utilitar- example, were considered to have been metal pro- ian pottery. An early expansive Bell Beaker phase is spectors, itinerant tinkers, or even warriors (Gerhardt, assumed to have appeared along the Lower Rhine 1978). Other interpretations of the phenomenon

517 518 G. Grupe et al. involved a highly mobile population that split into in terms of bulk composition (affecting *‘Rb/*‘Sr several groups as it moved across Europe. This ratios) and age, 87Sr/86Sr ratios on the surface are population was thought to be specialized in prospect- quite variable. ing, manufacturing, and trading prestige goods. It should be possible, therefore, to trace changes in Continuing archaeological investigations, however, residence in animals through analysis of Sr isotope raised new questions about the Bell Beaker. For ratios in hard tissues that formed at different ontoge- example, the materials were not spread continuously netic stages (Ericson, 1985; Price et al., 1994a,b; Sealy across Europe, but rather were found in patchy, er al., 1991, 1995). For this purpose, compact femoral island-like concentrations, as in southern Bavaria. bone and the dental enamel of the first permanent From this perspective, Engelhardt (1991), for exam- molar is used for analysis. Because of its rather low ple, prefers to view the Bell Beaker people as elite in a rate of turnover, compact femoral bone in adults society in which social strata crystallized as the contains Sr, which has been incorporated during the culmination of regional differentiation in the earlier last 5-10 a of life. Dental enamel, however, as a cell- Neolithic. free tissue does not undergo turnover after formation, Thus, the debate about Bell Beaker continues, and Thus, the Sr in the enamel of the first permanent molar the question of residential mobility remains unre- contains Sr that has been incorporated from birth to solved. Styles of pottery and other artifacts have been approximately 4 a of age (Hillson, 1989). Differences used instead of human remains to examine the in the Sr isotope signature between enamel and bone question of mobility and diffusion. The goal of the are therefore indicative of a change in residence during research described here is to examine the question of the individual’s lifetime. Such difference8 mean that Bell Beaker mobility from an archaeometric perspec- the individual was born in a place geologically and tive using the actual human skeletal remains for direct isotopically different from the place where it died. information on changes in residence. The question for Strontium isotope ratios in animal hard tissue have our research is whether or not Bell Beaker people been used, for example, to identify the origin of moved significant distances, or remained in the same illegally exported elephant ivory (Van Der Merwe et area, during their lifetime. The focus of our investiga- al., 1990; Vogel et al., 1990) or to reconstruct tions is Bell Beaker burials in southern Bavaria. More migration in salmon with appositional bone growth than 100 Bell Beaker sites have been excavated in this (Koch et al., 1992). Studies of humans have been area, with the majority found between the Danube reported for prehistoric American Indian groups in and the Alps. the Southwest United States (Price er al., 1994b; Ezzo The remainder of this paper describes the approach et al., 1997) and aboriginal populations in South that we are using-the characterization of bone and Africa (Sealy et al., 1991). A preliminary study of tooth using Sr isotope ratios, the geology and Bell Beaker skeletons, demonstrating the applicability archaeology of southern Bavaria, the results of our of the method, was reported by Price et al. (1994b). analyses, and some conclusions regarding the question of Bell Beaker mobility. The geology of Bavaria

The archaeometric approach Geologically, Bavaria can be divided into several zones. The Danube River separates a southern and The mineral matrix of hard human tissues (bones northern half (Fig. 1). The region northeast of the and teeth) consists mainly of largely insoluble Ca river is characterized by granites and gneisses with phosphate hydroxyapatite [Cais(PG&,(GH)z]. isotopic ratios exceeding 0.71. A rather detailed Sr Common substitution of Sr for Ca in this mineral isotopic map already exists for this area (Sollner, pers. produces high Sr concentrations in the order of 102- commun.). Sediments south of the Danube are partly IO3 ppm in hard tissue. In nature, Sr occurs in the glacial in origin, resulting in loess deposits close to the form of 4 stable isotopes (Faure, 1986): the most river. This area south of the river has not been abundant is **Sr (approximately 82.53%), followed by geologically mapped for Sr isotope ratios, but is *‘Sr and *‘?Jr (approximately 7.04% and 9.87%, characterized by lower values. For this reason, soil respectively), whereas 84Sr is least abundant (approxi- samples were collected from several sites, and Sr mately 0.56%). We present relative variations in *‘Sr isotope ratios were measured in the sediments. The abundances in materials by calculating a ratio with the values for these samples ranged between 0.70899 and non-radiogenic isotope, *‘jSr, following standard 0.70992 (Table 1); the mean and standard deviation convention (Faure, 1986). Since the relative mass for the four samples were 0.70938 and 0.00047, differences between *‘Sr and 86Sr is so small, no respectively. isotopic fractionation takes place during Sr transport The area covered by sediments along the Danube in any ecosystem (Graustein, 1989). For non-mobile has been inhabited since. the earlier Stone Age. The individuals, the 87Sr/86Sr ratio in hard tissue will sites of the Bell Beaker period are also indicated in Fig. therefore match the Sr isotopic composition of their 1, demonstrating the distribution of materials along habitat. Because the earth’s surface is highly variable the Danube River. The archaeological evidence leaves Mobility of Bell Beaker people, use of Sr isotopes 519

Fig. 1. Geology of Bavaria divided into zones. The Danube River separates a southern and northern half

no doubt that the Bell Beaker people came from the tissues were preserved. The skeletons had been found either (N)E and spread to the (S)W, following the rivers that in small burial sites (l&30 individuals: bsburg, hlbach, K+zing-Bruck, Landau, C&terhofen, Bichering) or as provided water, food, and transport. Bell Beaker single burials or very small groups of burials (no more than individuals, migrating from NE to SW through this 5 individua!s: <dorf, Landau, mnching, &mmelsbrunn, area, should show differences in isotopic ratios &aubing-Oberau, T&kelhausen). The underlined letters are between bone and enamel. used to designate each site in Fig. 1. Bone and enamel samples were washed and the surfaces removed mechanically (in Madison) or by ultrasonic etching (5 min in 99% HCOOH, Munich), ashed for 12 h at 500°C to METHODOLOGY remove the organic fractions, and finally homogenized To about 100 mg of homogenized sample was added a spike of The Bell Beaker skeletal material analyzed for this study is Sr (National Bureau of Standards, Washington, DC) with a housed in the Anthropological Collection, Munich, Ger- ratio of Sr:spike of 1:50. Samples were then solubilized many. The first permanent molar and compact cortical bone overnight in 3 ml of concentrated HNOs (Madison) or by was sampled from all Bell Beaker skeletons where both wet-ashing under pressure for 6 h at 160°C in 1 ml concentrated HNOs (Munich). After evaporation of the acid at 80°C the remnants were solubilized again in 3 ml of HCl and passed through a cation exchange column (20@-400 mesh, HCl as mobile phase) to separate Rb from Sr. The *‘Sr/*?3r Table 1. Sr ppm and s’Sr/*?Sr ratios for soil samples from ratio was determined by mass spectrometry. Standard the study area. The values from Straubing and Osterhofen reference material SRM 987 (National Bureau of Standards, are averages of samples Washington, DC) served as a quality control. In addition to 87Sr/86Sr ratios, the Sr content was also measured in the Site Sr ppm s7Sr/s6Sr samples using the isotope dilution method. The study was undertaken as a joint project between the Kiinzing-Bruck 159 0.70902 Universities of Munich (Germany) and Wisconsin-Madison Ktinzing-Bruck 163 0.70899 (U.S.A.). Approximately half the samples were analyzed at Straubing 166 0.70968 each locality. Several samples were analyzed in duplicate at Osterhofen 164 0.70992 the two laboratories for comparison of results. This compar- 520 G. Grupe et al.

Table 2. Comparison of non-standardized values from 1997). Because of the variation that is present in soil identical samples analyzed in Munich and Madison and bone data, any cut-off value to distinguish migrants is regionally specific and somewhat arbi- Sr ppm s7Sr/86Sr trary. In this paper, we present and discuss two Sample Munich Madison Munich Madison methods of determining the significance level for distinguishing immigrants: Landau, G.4,B 218 219 0.709164 0.708972 Weichering, G.D,T 126 131 0.712305 0.712821 (1) a value based on geological differences in the Weichering, G.D,B 292 251 0.708740 0.708847 area, and G: grave; B: bone; T: enamel. (2) a value based on bone Sr isotope ratios as an indicator of indigenous values in tooth enamel. Although the geochemical differences in 87Sr/*aSr ison was made to evaluate possible differences between ratios for the geology of this area appear to be small, laboratories in terms of instruments or procedures. These results (Table 2) demonstrate that the inter-laboratory results they are in fact highly significant. Modern mass are directly comparable. However, because of instrument spectrometers have a measurement error of between problems in Madison (3 different sets of collectors on the f 0.00003 and f 0.00001 for Sr isotope ratios. Thus, Madison mass spectrometer), all data have been standar- a difference of 0.001 (0.710-0.709) is the equivalent of dized to base Madison measurements (Table 3). Contamination of bone and tooth samples, or diagenesis, between 33.3 and 100 measurement units, depending is a well-known problem in trace element analysis of human on the precision. Migration from a granite/gneiss skeletal material (Price et al., 1992). However, diagenesis is area into a region dominated by carbonate-rich soils not a substantial problem in Sr isotope analysis. Acid thus should be reflected in the *‘Sr/*‘Sr ratios in bone cleaning of bone samples is generally effective in removing and enamel. Using a cut-off of 0.001 between the most contaminants (Price et al., 1994b). In addition, any contaminants remaining in bone or enamel samples would bone and enamel measurements, likely immigrants exhibit 87Sr/8sSrratios of the local geology. Thus, any values can be identified. Figure 3 shows burials from the that indicate residential changes and different geogieal source Augsburg site. Immigrants are readily detected, and materials are clearly not heavily contaminated. the geological boundary between granitelgneiss and carbonate soils, marked by the Danube River, is distinctive. Augsburg is located some distance from RESULTS this boundary; approximately 220 km in the migration route was along the river valleys. Using the cut- The results of our analyses of tooth and bone from off point of 0.001, 16 of the total of 69 burials from Bell Beaker burials in Bavaria are presented in Table the Bell Beaker period are distinguished as immi- 3. This table includes site and burial number, age and grants. Since, in those individuals where only a tooth sex of the burial, s7Sr/*6Sr ratios and Sr ppm for tooth specimen was available for analysis, the respective and bone samples from the burial. A total of 77 isotopic ratio agrees with the isotopic characteristic individuals are listed in the table. Two burials from the of the burial site, these individuals were not con- site of Weichering (Burials A and D) later were sidered as mobile. There was, however, one excep- discovered to be younger, from the La Terre period tion: The Bell Beaker child from Straubing in grave 1 of the Iron Age. Samples of bone or tooth were not (Table 3) has a Sr isotope ratio in tooth enamel of available from 6 of the individuals. Thus, the Bell 0.71621 (no compact femoral bone was available). Beaker sample includes 69 individuals analyzed for This child must have moved a substantial distance in both bone and tooth enamel. This is the largest sample the early years of its life. Thus, a total of 17 of the 69 of *7Sr/86Sr ratios in human tissues available any- Bell Beaker individuals, almost 25%, moved resi- where to date. dence to new geological regions during their life- The number of burials and number of bone/tooth times. pairs of samples per site is given in Table 4. Age and We also report a second cut-off value, the mean + 2 sex information on the burials is summarized in standard deviations of all bone 87Sr/s6Sr values, or Tables 5 and 6. These tables do not include the two 0.709041 f(2 x 0.000616). Bone values should repre- Iron Age burials from Weichering. sent a reasonable estimate for long-term residents of Mean values for 87Sr/86Sr ratios and Sr ppm for the area. The bone mean + 2 S.D. value is 0.7103. This tooth and bone samples are also presented in Table 3. bone value is used as a cut-off point in the enamel Strontium values in tooth enamel (X-99) are sig- 87Sr/86Sr data to distinguish immigrants. This value nificantly lower than in bone (X= 256) (cf. Figure 2). substantially exceeds the maximum *7Sr/86Sr value for Mean values for 87Sr/86Sr ratios are higher in enamel soil samples from the project area (0.70992) and is a (0.70967) than in bone (0.70904) as would be expected very conservative estimate of immigration. In addi- in a population with residential mobility, where tion, this value falls in a natural break in the individuals change their place of residence during life distribution of enamel ratios (Fig. 3), supporting its in a geologically variable area. use as a cutoff point. 13 samples lie beyond the cut-off Several approaches could be used to distinguish value of 0.7103, or 17.5% of the total number of immigrants using the Sr isotope data (cf. Ezzo et al., enamel samples that were analyzed. Thus, our best Mobility of Bell Beaker people, use of Sr isotopes 521

Table 3. Archaeological, anthropological and archaeometrical data

Tooth ppm Tooth Bone ppm Bone Bone-Tooth Tooth-Bone Site Grave Age Sex Sr 87Sr/86Sr Sr “Sr/‘% Lab ref. Sr s7Sr/%r

Al 17112 Juvenile Male 62 0.71001 128 0.71009 4 66 -0.00008 Al 180/3 Adult Male 63 0.70849 190 0.70962 4 127 -0.00113 Au 1 Adult Male 170 0.70864 303 0.70837 2 133 0.00027 Au 2 Adult Male 98 0.70882 440 0.70806 342 0.00076 Au 3 Adult Male 261 0.70826 368 0.70806 : 107 0.00020 Au 4 Adult Female 142 0.70861 274 0.70821 132 0.00040 Au 5 Adult Male 127 0.70866 296 0.70821 : 169 0.00045 Au 8 Adult Male 150 0.70838 390 0.70814 240 0.00024 Au 9 Juvenile Female 78 0.71169 451 0.70818 : 373 0.00350 Au 10 Adult Male 133 0.71638 378 0.70825 1 245 0.00813 Au 13 Child - 78 0.70840 3 Au 14 Adult Male 113 0.70858 372 0.70822 3 259 0.00036 Au 15 Juvenile Male 125 0.70842 341 0.70826 2 216 0.00015 Au 16 Adult Female 189 0.70832 306 0.70822 3 117 0.00810 Au 17 Adult Female 160 0.70853 402 0.70831 2 242 0.00022 Au 19 Child - 96 0.70846 3 Au 20 Male 103 0.70837 376 0.70833 3 273 0.00005 Au 21 Child - 70 0.70975 3 Au 22 Adult Female 158 0.70868 348 0.70858 3 190 0.00010 Ir 1 Adult Female 60 0.71001 0.71092 4 -0.08091 Ir 3 Adult Male 110 0.70955 332 0.70952 4 222 0.00003 Ir 4 Child Female 91 0.70963 4 Ir 6 Adult Female 252 0.70913 252 -0.70913 Ir 7 Child - 12 0.70956 44 Ir 9 Adult Female 197 0.70955 328 0.70932 4 131 O.ooO23 II 10 Adult Male Ill 0.7093 1 294 0.70938 4 183 -0.ooOo7 Ir 14 Adult Male 106 0.70932 254 0.70914 4 148 0.00018 Ir 16 Adult Male 109 0.71150 276 0.70933 4 167 0.08217 Ir 20 Adult Male 136 0.70973 349 0.70922 4 213 0.00051 Ir 21 Adult Female 85 0.70991 281 0.70901 4 202 0.00090 Ir 22 Adult Female 78 0.70964 328 0.70929 4 250 0.00035 Kti 278 Adult Male 65 0.70882 227 0.70928 3 161 -0.00045 Kti 332 Adult 77 0.70886 248 0.70879 171 o.OoOO7 Ku 335 Adult Male 0.70938 281 0.70902 : 226 0.00036 Ku 338 Adult Male !z 0.70892 204 0.70925 3 112 -0.00032 Kii 349 Adult Male 43 0.70960 227 0.70905 3 184 0.00055 Kii 372 Female 61 0.70951 320 0.70866 253 0.00085 La 2 Child - 70 0.70949 : La 3/l Child - 54 0.70944 3 La 4 Adult Female 49 0.71081 219 0.70897 394 171 0.00184 La 5 Adult Female 51 0.71124 140 0.70957 3 89 0.00168 La 7 Adult Female 99 0.70926 174 0.70884 3 15 0.00041 La Child - 47 0.70990 3 La ; Adult Female 302 0.10861 211 0.70912 3 -92 -0.00045 La 101 Adult - 0.71108 121 0.70978 76 0.00130 La 103 Adult - :: 0.71014 201 0.70913 : 136 0.00101 Ma 1 Adult Male 64 0.70923 179 0.70871 3 114 0.00051 Ma 2 Adult Male 196 0.70846 220 0.70871 23 - 0.00026 Ma 4 Adult Female 0.71122 210 0.70899 : 128 o.OQ223 OS Adult Male ;: 0.70924 178 0.70935 3 85 -0.00011 OS : Adult Male 50 0.70986 233 0.70918 3 183 0.00068 OS 10 Adult Female 256 0.70915 228 0.78904 3 -28 0.00011 OS 21 Adult Male 100 0.70928 185 0.70911 3 85 0.00017 OS 25 Adult 42 0.70960 236 0.70903 193 0.00057 OS 28 Adult Female 55 0.71077 262 0.70904 : 207 0.00172 OS 29 Adult Female 118 0.70893 209 0.7094s 3 92 -0.00051 OS 30 Adult Male 0.71060 208 0.70938 3 150 0.00122 PO 1 Adult Male :; 0.71054 64 0.70998 33 0.00056 Str 1 Child - 149 0.71624 t str 4 Juvenile - 55 0.70986 24: 0.70997 4 186 -0.00011 Adult Male 104 0.71006 237 0.71008 4 133 -0.00002 strStr 178 Adult Male 0.70919 225 0.71039 161 -0.00120 Str 18 Adult - z 0.71061 194 0.71001 44 160 O.OQO60 Tii Eo Adult Male 147 0.70972 225 0.70985 4 78 -0.09013 TiJ Eu Juvenile Male 0.70964 215 0.70978 4 137 -0.00014 We 3 Adult Male ;: 0.70938 255 0.70870 171 0.00068 We 4 Child - 68 0.70917 : 522 G. Grupe et al.

Table 3. (Continued)

Tooth Bone ppm Bone Bone-Tooth Tooth-Bone Toot;rppm 87Sr,86Sr Site Grave Age Sex Sr 87Sr/86Sr Lab ref. Sr 87Sr/86Sr

We 4 Child - 68 0.70917 3 We 5 Juvenile Male 90 0.70888 266 0.70870 I 176 0.00018 We 10 Adult Male 70 0.70886 282 0.70867 3 212 0.00019 We 12 Child - 91 0.70913 3 We 13 Child - 80 0.70910 3 We 14 Adult Female 102 0.70868 322 0.70872 3 220 -0.00004 We 17 Adult Male 89 0.70958 306 0.70857 1 217 0.00102 We 18 Adult Male 79 0.70861 289 0.70905 3 210 -0.00044 We 19 Adult Male 57 0.71066 284 0.70885 3 227 0.00181 We A Adult Female 120 0.70992 368 0.70861 I,4 248 0.00131 We D Adult Female 131 0.71288 251 0.70891 1,4 121 0.00397 Average: 99 0.70967 266 0.70904 Maximum: 302 0.71638 451 0.71092 Minimum: 31 0.70826 64 0.70806

Lab ref no. 1: UW Madison, December 1992, NBS-987 =0.71020 (2SD of 0.00008; n=4). Old collectors. Lab ref no. 2: UW Madison, March 1994, NBS-987=0.71023 (2SD of 0.00010; n= 13). Old collectors. Lab ref no. 3: UW Madison, 1995, NBS-987 = 0.7 1026 (2SD of 0.00002; n = 100 +). New collectors. Lab refno. 4: German lab, NBS-987=0.71023 (f0.00001; n= 10). All data normalized to NBS-987 =0.71026.

Table 4. Number of analyzed Bell Beaker burials per estimate for the number of immigrants in the Bell cemetery and tooth/bone samples from the same individual Beaker burials from southern Bavaria ranges between 17.5 and 25%. More detailed analysis of the data also Cemetery Number of burials T/B pairs provides interesting information. Examination of the individual sites indicates a tendency for more migra- Altdorf 2 2 Augsburg 17 14 tion in the older part of the Bell Beaker period (Table Irlbach 12 9 7). The larger sites of Irlbach, Augsburg, and K&zing-Bruck 6 6 Weichering are dated to the younger phase of the Landau 9 6 Bell Beaker period. The larger cemeteries of the Manching 3 3 Osterhofen 8 8 younger phase contain more burials, 20-30 inhuma- Pommelsbrunn 1 1 tions, perhaps an indication of a more sedentary Straubing-oberau 5 4 population. Ttickelhausen 2 2 Weichering 10 7 Histogram

Table 5. Age of Bell Beaker burials

Age Number of burials

Child 12 0 Juvenile 7 50 100 150 200 250 300 350 400 450 500 Adult 53 Bone Sr ppm Unknown 1 Histogram

IO 6 g 8 Table 6. Sex of Bell Beaker u 6 burials 4 Sex Number of burials 2 n Male 38 0 50 100 I50 200 250 300 350 Female 24 Tooth Sr ppm Unknown 13 Fig. 2. Histograms of Sr ppm for bone and tooth enamel. Mobility of Bell Beaker people, use of Sr isotopes 523

500

450 ,Oo

?? Au tooth 0 Au bone - cut-off 400 ., 0 * Soils - all teeth ?? all bones Ck

0 , 0.708 0.709 0.710 0.711 0.712 0.713 0.714 0.715 0.716 0.717 8lSrl86Sr Fig. 3. Strontium isotope. ratios in all Bell Beaker buriah with the Augsburg site as a special example, plotted against Sr ppm.

With regard to sex, females were somewhat more DISCUSSION mobile than males. Some 62 of the skeletons could be sexed either anthropologically or archaeologically; 38 Since the skeletal morphology of the Bell Beaker were males, and 24 were females. An equal number of skeletons is distinct from the earlier Neolithic people males and females (8 each) were mobile using the 0.001 in the region of southern Bavaria, it could be assumed cutoff value. Thus, a higher proportion of females that the Bell Beaker people were indeed migrants into appear to be immigrants; this pattern is present at the this area. However, morphology alone is not proof of individual sites as well. migration since the underlying genetic controls of The overall direction of migration for the Bell bone size and shape are still unknown. At present, Sr Beaker people, based on the Sr isotope data is from isotope analysis is the only means for a direct NE to SW. The next adjacent region to the SW is the assessment of residence change during a lifetime southern alpine area, which lacks Bell Beaker sites. A capable of distinguishing migrant individuals from southern origin is possible for the two La T&e Iron indigenous ones. Age burials from Weichering. The proportion of migrant individuals in our samples lies between 17.5 and 25%. Does this represent a high or low rate of migration? The number of living individuals at a given burial site is calculated from life table data based on the number of dead encountered, using the formula p Dxes Table 7. Sample size and immigrants at individual Bell =-+k, Beaker sites t Number of Number of Percentage where P = number of living individuals; D = number Site samples immigrants immigrants of excavated burials; e,”= average life expectancy at birth; t = time during which the burial site was in use; Irlbach 12 2 16.7 and k = correcting factor (Herrmann et al., 1990). This Augsburg 14 2 14.3 Osterhofen 8 3 37.5 correction factor, k, equals 10% of D x ei/t and is Altdorf 2 1 50.0 based on historical data, considering that members of Landau 9 4 44.4 the population may have died and been buried at a Straubing 5 2 40.0 different place. Thus, an average emigration rate of Manching 1 33.3 Weichering : 2 33.3 10% is assumed. Although emigration and immigration rates need not be identical, both figures should be Cut-off value of 0.001 is used to identify immigrants. balanced somehow in a given region as long as there is 524 G. Grupe et al. an absence of indicators for gross population growth early childhood and the last years before death. If or decline. If this “rule of thumb” of 10% emigration values for both tooth and bone are similar, as is the also holds for the late Neolithic, the mobility of the case for 75% or more of the population that we Bell Beaker people with 17.5525% mobility was analyzed, no movement is signalled. We are unable to indeed very high. We should also note that the Sr determine, however, whether an individual moved isotope technique will only identify those individuals back and forth between areas during its lifetime, or moving between geologically distinct regions. Inter- whether an individual changed residence, but only regional movement will not be distinguished. In this within the same geological province. For these context, the Sr isotope technique underestimates the reasons, our results likely underestimate the amount amount of mobility in the population. It will be of residential mobility in the Bell Beaker period. We important to examine s7Sr/86Sr values in other conclude, therefore, that Bell Beaker people in south- populations to determine rates of migration in ern Bavaria were indeed highly mobile bearers of their prehistory. culture. We can only roughly estimate the minimal distances traversed by some migrant individuals since a rela- Acknowledgements-This research was supported in large part by the Deutsche Forschungsgemeinschaft to Gisela tively high 87Sr/86Sr value in tooth enamel only Grupe. Additional funding from the National Science indicates an origin NE of the Danube River but does Foundation to T. Douglas Price (BNS-8702731), to T. not indicate how far from this geochemical boundary Douglas Price, James H. Burton, and Clark M. Johnson the individual was raised. Graves 9 and 10 at (BNS-9111680), and to Clark M. Johnson (EAR-9105966, Augsburg contained two migrant individuals at the EAR-9406684. and EAR-9304455). Samole oreoaration and laboratory work in Madison was done’in’fin~ fashion by maximum distance from the granitic deposits north- Kathie Evans and Bill Middleton, in Munich by Dirk east of the Danube. If those two individuals traveled Weickmann. along the rivers, first to the W and then to the S, the total distance involved was at least 220 km. Editorial Handling: Prof. P. Fritz. For a pioneering population moving into an unknown region, it may have taken years or even generations to cover such a distance (Hassan, 1981). REFERENCES However, for migration into an already settled region, such as southern Bavaria in the late Neolithic, this De Laet S. J. (1994) Europe during the Neolithic. In History distance of 220 km may have been covered in a few of Humanity, Prehistory and the Beginnings of Civilization (ed. S. J. De Laet), UNESCO, Vol. I, pp. 490-500. weeks or months. The hypothesis that this area was Engelhardt B. (1991) Beitriige zur Kenntnis der Glocken- already well known is supported by evidence from becherkultur in Niederbayern. Kurze Einftihrung in die Grave 9 at Augsburg, a migrant female who died at Glockenbecherkultur, Vortr. 9. Niederbayer. 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