Strontium isotope analysis in ancient glass from South Asia using portable laser ablation sampling

In order to carry out strontium (Sr) isotope analysis, glass artefacts from South Asia were sampled with portable laser ablation (pLA), a relatively novel sampling technique that leaves damage invisible to the naked eye. Subsequently, thermal ionization mass spectrometry (TIMS) was used to obtain Sr isotope ratios after sample dissolution and separation. In this study, the goal was twofold: to determine whether the measurements of Sr isotope ratios were impacted by using a portable laser as a sample tool; and to assess the pertinence of using Sr isotope ratios to provenance Indian glass. Despite a deterioration in the precision of the measurement of the Sr isotope ratios for artefacts sampled with pLA compared with the traditional sampling method, the Sr isotope ratios of certain Indian glass are so different that this does not affect their separation but a comparison of data sets obtained using standard methods and pLA might be challenging.     

Study on the strontium isotope standard in pig teeth excavated from Zaoshugounao site,Shaanxi Province of China

In archaeology, strontium isotope analysis is developing into an efficient scientific technique for tracing the movement of prehistoric humans and animals. Determining the local bioavailable ⁸⁷Sr/⁸⁶Sr ratio range is the key to distinguishing whether the human or animal is indigenous to the local area. It has been shown that the ⁸⁷Sr/⁸⁶Sr ratio in the enamel of pigs can be an excellent sample to determine the range of local strontium isotope ratio at the site. However, pigs may not be all local at the site, and there is no special study on whether pigs’ different ages and tooth types impact the local strontium isotope characteristics. In this paper, the tooth enamel of 19 pigs from the Zaoshugounao site for strontium isotope ratio (⁸⁷Sr/⁸⁶Sr) by multicollector–inductively coupled plasma mass spectrometry. There were no significant differences in ⁸⁷Sr/⁸⁶Sr ratios of local pigs at different months and different molar types, which did not affect the determination of the local strontium isotope standard. Based on the local strontium isotope ratio range (0.711056–0.711476), we found that five pigs were non-local. The Jing and Wei river basins (in Guanzhong basin) and northern Shaanxi are likely sources of non-pigs.     

Effect of mollusc eating on human bone strontium levels

Empirical aspects of the movement of strontium through the food chain suggest that the level of bone strontium can be used as an indicator of the percentage of meat in human diet. In general, skeletal remains from agricultural peoples are expected to have high bone strontium levels relative to hunter-gatherers from the same geographical region because plants contain relatively higher amounts of strontium when compared with animal products. The results of the study described in this paper, however, indicate that the inclusion of molluscs as a component of the diet may produce the opposite of the expected strontium values. Burials from an Archaic (c. 2500 BC) hunting-gathering population excavated from Lu^o25, an archaeological site in northern Alabama, USA, exhibit a mean bone strontium level ( atomic absorption; neutron activation) that is higher than the mean level from an agricultural Mississippian (c. AD 1400) population ( atomic absorption; neutron activation) that was buried at the same site. The samples were analysed by two techniques (atomic absorption spectrometry and neutron activation analysis) and the results compared favourably; therefore, the results can be accepted as valid rather than being due to technique error. We propose that the ingestion of molluscs, whose meat is known to contain large amounts of strontium, has produced this reversal from expected results.     

Investigating Human Migration and Horse‐Trading in Yelang (夜郎) Through Strontium Isotope Analysis of Skeletons from Zhougshui Sites,South‐West China (1300 bc – ad 25)

Yelang (夜郎), a mysterious state located in the south‐western area of early China and dating from the Bronze Age to the Early Iron Age (1300 bc – ad 25), is a cultural interactive junction between the Yunnan–Guizhou Plateau and the Yangtze River Basin. The Zhongshui Basin in Weining County, Guizhou Province, was one of the important distribution areas of the Yelang civilization. This area, which includes sites at Jigongshan (鸡公山; 1300 – 800 bc ), Hongyingpan (红营盘; 700 – 400 bc ) and Yinzitan (银子坛; 400 bc – ad 25), has provided a very integrated chronology, spanning from the Bronze Age to the Early Iron Age in the eastern Yunnan – western Guizhou area. To investigate human migration and horse‐trading at these Yelang sites, we conducted a strontium isotopic analysis on the teeth enamel of humans and horses unearthed from these three sites. The results indicated the following: (1) people at the earlier sites (Jigongshan and Hongyingpan) were all indigenous, whereas in the Yinzitan cemetery, there was a more immigrant population, and all the people who were buried in an upper limb flexed supine position were non‐local; and (2) most of the horses found at the Jigongshan and Yinzitan sites show different provenances, probably related to the famous Dian (滇) and Zuo (筰) horses recorded in historical documents, providing more clues for further study on horse‐trading in South‐West China during the Bronze Age and the Early Iron Age.     

The Movement and Exchange of Dogs in the Prehistoric Caribbean: An Isotopic Investigation

This study explores the feasibility of using strontium isotope (⁸⁷Sr/⁸⁶Sr) analyses of enamel from domestic dogs (Canis familiaris) to investigate networks of exchange in the prehistoric Circum‐Caribbean. Dog teeth were obtained from burial and domestic contexts from two prehistoric sites (Anse à la Gourde and Morel) on Grande‐Terre, Guadeloupe (Lesser Antilles). Strontium isotope results were compared with local biosphere ⁸⁷Sr/⁸⁶Sr data at the scale of the site, island and archipelago. The isotope results indicate both local and nonlocal origins with three dogs (30%) identified as nonlocal (one from Anse à la Gourde and two from Morel). The variance in ⁸⁷Sr/⁸⁶Sr ratios of the nonlocal dog teeth is consistent with diverse multiple origins external to the island of Grande‐Terre but consistent with origins from other islands of the Lesser Antilles. The diverse origins of the nonlocal dog samples indicate that the prehistoric circulation of dogs occurred at multiple scales from regional to long distance. Significantly, the ⁸⁷Sr/⁸⁶Sr ratios of some of the dog teeth are comparable with values of nonlocal humans at Anse à la Gourde determined in previous studies. It is possible that these comparable ⁸⁷Sr/⁸⁶Sr ratios result from similar natal origins, for example if individuals were migrating to Guadeloupe with dogs. The results of this study contribute to an ongoing regional investigation of the economic, social and political roles of animals and animal remains and the multiscalar networks of prehistoric mobility and exchange in the Circum‐Caribbean region. Copyright © 2013 John Wiley & Sons, Ltd.     

Human Response to Climate Change during the Umm an‐Nar/Wadi Suq Transition in the United Arab Emirates

Stable oxygen isotope ratios in archaeological human dental enamel represent an under‐utilised tool in the examination of changing climatic patterns in the ancient world. In the Oman Peninsula at the end of the third millennium bc , rapid aridification was accompanied by a breakdown in interregional trade relations; however, the human response to these changes is poorly understood. At the Bronze Age necropolis at Shimal in the United Arab Emirates, dental enamel from individuals interred in both Umm an‐Nar (ca 2700–2000 bc ) and Wadi Suq (ca 2000–1300 bc ) tombs underwent oxygen, strontium and carbon isotope analyses to examine how local inhabitants of southeastern Arabia responded to both environmental and socioeconomic change. While individuals from Shimal exhibit a clear shift in mean δ¹⁸O_c(VPDB) values from the Umm an‐Nar (−3.5 ± 0.6‰, 1σ) to the Wadi Suq (−2.4 ± 0.9‰, 1σ), corresponding ⁸⁷Sr/⁸⁶Sr and δ¹³C_ap signatures display homogeneity indicative of continuity in Bronze Age lifeways. Together, these data highlight the ability of local communities to successfully adapt to their changing environs (in lieu of societal collapse or a shift to a more mobile lifestyle) in an effort to maintain their way of life. Copyright © 2014 John Wiley & Sons, Ltd.     

Neolithic nomadism in south‐east Arabia — strontium and oxygen isotope ratios in human tooth enamel from al‐Buhais 18 and Umm al‐Quwain 2 in the Emirates of Sharjah and Umm al‐Quwain (UAE)

Human skeletal remains from the Neolithic sites BHS18 in the interior of the Sharjah Emirate and the Neolithic shell midden UAQ2 (Umm al‐Quwain) on the coast of the Persian Gulf (United Arab Emirates, UAE) were analysed for their isotope ratios of strontium (⁸⁷Sr/⁸⁶Sr) and oxygen (¹⁸O/¹⁶O). The results are not in agreement with earlier assumptions about a Neolithic nomadism between inland regions and the south‐eastern coast of the Persian Gulf. Existing evidence of nomadic movements of the people from BHS18 most possibly refers to transhumance within the mountains in the hinterland. The strontium isotope measurements on human skeletons from UAQ2 on the contrary indicate uninterrupted residence of this population on the coast. Nevertheless, evidence was found of individual mobility between inland regions and the coast.     

The Zoutsteeg Three: Three New Cases of African Types of Dental Modification from Saint Martin,Dutch Caribbean

Dental modification was widely practiced in sub‐Saharan Africa as a form of cultural expression, and during the era of the transatlantic slave trade, it was regularly identified in enslaved Africans who were transported to the Americas. Here, we report three new cases of African types of dental modification from the Caribbean island of Saint Martin that were recently encountered during construction activities in the Zoutsteeg area of Philipsburg, the capital of the Dutch half of the island. The artifacts associated with the burials indicate that they date to the late 17^th century, prior to the foundation of the town of Philipsburg in 1735. The dental evidence further suggests that the three individuals were born in Africa, as opposed to the Americas. This could be confirmed by tooth enamel strontium isotope measurements which yielded values that are inconsistent with an origin in the Caribbean but consistent with an origin in Africa. Unfortunately, neither the dental patterns nor the strontium isotope values allow us to determine their specific origins in Africa. However, both the methods used to modify the teeth and the isotope ratios suggest that the ‘Zoutsteeg Three’ originated in different parts of Africa. Copyright © 2012 John Wiley & Sons, Ltd.     

Strontium isotopic characterization of the Palmottu hydrosystem (Finland): water–rock interaction and geochemistry of groundwaters

The Palmottu hydrosystem is located in a granitic host rock in southern Finland. Along well‐defined pathways in the fractured crystalline rock, strontium isotopes are used to trace the degree of water–rock interaction (WRI) and mixing processes in groundwaters. The ⁸⁷Sr/⁸⁶Sr ratios range between 0.716910 and 0.735606 in the surface waters and between 0.719991 and 0.750787 in the groundwaters, but are between 0.720 and 0.735 in most of the samples. Moreover, the results show a lack of correlation between the water chemistries determining the classification into different water‐types (Na–Cl, Na–SO₄, etc.) and the results of the strontium (Sr) contents and Sr isotopic ratios. From a WRI standpoint, this implies that the Sr behaviour is independent of the water chemistry; the occurrence of large ⁸⁷Sr/⁸⁶Sr variations is site specific and mainly dependent on the lithology. A model to determine the ⁸⁷Sr/⁸⁶Sr ratio of water after interaction with granite was developed. This model is based on the assumption that Sr was derived from three minerals: plagioclase, K‐feldspar and biotite. The results of the calculation indicate that around half of the water analysed within the Palmottu hydrosystem can be explained by the weathering of the granites. However, clearly lower ⁸⁷Sr/⁸⁶Sr are observed in waters when compared to the calculated ⁸⁷Sr/⁸⁶Sr and other sources of Sr, with low ⁸⁷Sr/⁸⁶Sr, rather than the calculated granite–water interaction, which may be suspected. When comparing the ⁸⁷Sr/⁸⁶Sr and ion ratios (Ca/Na, Mg/Na, Sr/Na, Cl/Na), the scattering of the data can be explained by the presence of four end‐members: a brine component (low ⁸⁷Sr/⁸⁶Sr and Ca/Na ratios…), a deep granitic component (high ⁸⁷Sr/⁸⁶Sr ratios and low Ca/Na ratios…), a subsurface component (intermediate ⁸⁷Sr/⁸⁶Sr ratios associated with high Ca/Na ratios…) and a surface end‐member:snow and river drainage (low ⁸⁷Sr/⁸⁶Sr and low Ca/Na ratios…). These extreme end‐members define a series of WRI‐mixing line within a rather complex hydrosystem.     

Introducing δSr analysis in archaeology: a demonstration of the utility of strontium isotope fractionation in paleodietary studies

Isotopic methods are widely used in archaeology to investigate paleodiet. Here, we present a new method to identify trophic level in archaeological human populations and to investigate paleodiet. We demonstrate that strontium isotope compositions (reported as δ^88/86Sr) vary in a mass-dependent manner with increasing trophic level and can elucidate paleodiet in archaeological human populations. We present new mass-dependent strontium isotope data from tooth enamel and bone from individuals buried during the Late Intermediate Period (c. AD 1000–1300) in the large cemeteries of Chiribaya Alta, Chiribaya Baja, San Gerónimo, and El Yaral in the Ilo and Moquegua Valleys of southern Peru. We compare these data to radiogenic strontium isotope data (⁸⁷Sr/⁸⁶Sr) and light stable isotope data (δ¹⁵N_col and δ¹³C_col) from the same individuals to investigate geologic variability in strontium sources as well as marine food consumption among the Chiribaya. Our results demonstrate the utility of measurements of strontium isotope fractionation as a new tool for archaeological investigation of paleodiet. Importantly, this new technique can be used to generate paleodietary (δ^88/86Sr) and paleomobility (⁸⁷Sr/⁸⁶Sr) data from the same specimen, minimizing destructive analyses of invaluable archaeological material, and provides a new way to examine paleodiet through hydroxyapatite, which is particularly important when collagen is poorly preserved.