Did China Import Metals from Africa in the Bronze Age?

The origins of the copper, tin and lead for China's rich Bronze Age cultures are a major topic in archaeological research, with significant contributions being made by archaeological fieldwork, archaeometallurgical investigations and geochemical considerations. Here, we investigate a recent claim that the greater part of the Shang‐period metalwork was made using metals from Africa, imported together with the necessary know‐how to produce tin bronze. A brief review of the current status of lead isotopic study on Shang‐period bronze artefacts is provided first, clarifying a few key issues involved in this discussion. It is then shown that there is no archaeological or isotopic basis for bulk metal transfer between Africa and China during the Shang period, and that the copper and lead in Shang bronze with a strongly radiogenic signature is not likely to be from Africa. We call for collaborative interdisciplinary research to address the vexing question of the Shang period's metal sources, focusing on smelting sites in geologically defined potential source regions and casting workshops identified at a number of Shang settlements.     

The bronze artifacts from the Yejiashan site and the political presence of the Zhou dynasty in the middle Yangtze Plain: an application of lead isotope analysis

Lead isotope ratios of 15 Chinese bronze artifacts from the Yejiashan site (Suizhou City, Hubei Province) were analyzed and compared with copper ores across China. This study attempts to provide a new perspective to discuss the role that Zeng State played among all the vassal states in the early Zhou dynasty (ca. 1046–977 BC). The political presence of the Zhou dynasty in the middle Yangtze Plain is another main content of this paper. The lead isotopic characteristics of Chinese bronze artifacts between different historical periods are also in the scope of the study. By comparison, the lead isotopic ratios of the tested bronzes and copper deposits in the north Jiangxi Province show numerous overlaps. It indicates that the tested bronzes might have a single ore source, and this source was in the south of the Zhou dynasty. Combined with history and archaeological records, it is highly likely that the middle Yangtze Plain might be a part of the Zhou dynasty since the very beginning. Moreover, Zeng State might have a great influence in the ancient middle Yangtze Plain, and the nobles of Zeng State might even have authority to supervise certain area extending to Jiujiang. As lead isotopes of the bronzes appear to show a clear relation to chronology, the change of lead isotope patterns across times may further serve to distinguish the bronzes of the Western Zhou dynasty from the late Shang ones.     

Geochemical impacts to prehistoric iron-rich siliceous artifacts in the nearshore coastal zone

In the Middle Atlantic region of the United States, landscapes drowned by sea level rise contain scores of prehistoric archaeological sites. These sites provide archaeologists with a rare opportunity to investigate various geologic processes. During the transition from a terrestrial to an offshore setting, the materials associated with an archaeological site are exposed to a series of geochemical processes inherent to the formation of tidal marsh. The duration of the geochemical exposure to tidal marsh is largely dependent on the rate of marine transgression. Here we describe the stages associated with the sulfidization and sulfuricization scheme and the impact to iron-rich lithic artifacts from naturally drowned archaeological sites. Sulfidization and sulfuricization should also impact buried archaeological materials as a result of anthropogenic dredge spoil dumping and the creation of man-made tidal marshes along modern coastlines. Our results indicate that the surfaces of an iron-rich artifact, as well as its interior are visually and geochemically altered by prolonged exposure to the anaerobic conditions of a tidal marsh. Not only should researchers be cautious about making lithic material identification on artifacts found within coastal tidal marsh areas, but museum curators should be aware of the damaging impact of long-term aerobic storage. The geochemical tidal marsh scheme that has altered or corroded iron-rich lithic artifacts in the nearshore zone is an expression of a process that has impacted numerous earlier prehistoric sites currently located on the continental shelf or beneath the coastal estuaries around the world.     

Recent Research on Obsidian from Missouri Archaeological Sites

Obsidian has been noted at archaeological sites in the Midwest for over 160 years, although very few artifacts made from this material are recorded in archaeological contexts in Missouri. Background research revealed that only 16 obsidian artifacts from 13 sites had been documented from the state and that only 5 of the specimens had been geochemically analyzed and attributed to a source. Recent excavations at the Droste site (23PI1291), a Late Woodland period site in northeast Missouri, yielded two obsidian artifacts. The two specimens from the Droste site along with two previously unsourced obsidian artifacts from the Burkemper site (23LN104) and two from the Stapleton site (23HD110) were tested for trace element composition via X-ray fluorescence analysis. This article reports the results of these geochemical analyses, reviews the other obsidian artifacts reported from Missouri, and examines the cultural context and source of obsidian artifacts from other states in the upper Midwest.     

THERMI ON LESBOS: A CASE STUDY OF CHANGING TRADE PATTERNS

Summary Provenance studies on archaeological metal objects rely on their trace element abundance pattern and lead isotopic composition. A comparison of these features in artifacts from different archaeological sites often requires a comparison of results reported by different laboratories. In this case reasonable conclusions can only be expected if it is assured that the respective laboratories produce compatible results. A comparison of some twenty copper-based artifacts from Thermi I and II shows this compatibility still to be less than perfect between Oxford and Heidelberg — Mainz. We find the lead isotopic compositions reported by the two laboratories to agree within the stated uncertainties of the abundance ratios of 0.1 percent. The same is also true, to within 50 percent or better, for the contents of As, Sb, Ag, Au and possibly Ni. Serious discrepancies exist, however, for Co, Pb and Zn that we argue to be due to analytical problems at Oxford. Discriminant analysis of the data from all metal-bearing occupational levels at Thermi reveals a remarkably good correspondence between trace element signature and occupational level which suggests that at the beginning of the third millennium BC intercourse between Lesbians and Aegean metal traders was rare. Lead isotope data show that the change in metal, at least that upon the transition from Towns I + II to Towns III–IV, was indeed due to a change in source region of the metal and not one caused by a change in technology.     

First Geochemical ‘Fingerprinting’ of Balkan and Prut Flint from Palaeolithic Romania: Potentials,Limitations and Future Directions

Long‐distance raw material transfers across Romania prior to the Last Glacial Maximum have previously been inferred from either visual and/or petrographic observations of East Carpathian sites. We investigated the potential to ‘fingerprint’ flint from archaeological sites at Mitoc‐Malu Galben and Bistricioara–Lut?rie III in Eastern Romania, using in situ high‐precision analyses of 28 major, minor and trace elements determined by laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS) in combination with multivariate statistical analysis. Our results suggest that geochemical analyses have the ability to distinguish between different geographical sources but are unable to positively associate flint artefacts from archaeological contexts to these geochemical groups. The mismatches of signatures between artefacts and geological materials, however, raise new questions and open unforeseen perspectives.     

Assessing the applicability of portable X-ray fluorescence spectrometry for obsidian provenance research in the Maya lowlands

Recent innovations in portable energy-dispersive X-ray fluorescence (PXRF) spectrometry have increased its utility for the geochemical characterization of obsidian artifacts for archaeological provenance research. However, concerns over the utility of PXRF instrumental analyses have been raised, focused on the validity and reliability of the geochemical data produced. Here we adopt the framework of Richard Hughes (On Reliability, Validity, and Scale in Obsidian Sourcing Research, 1998), whereby reliability addresses instrument stability and issues of measurement while validity pertains to an instrument’s ability to discern geochemical source provenance. This is done in order to test the utility of PXRF instruments for archaeological provenance research. k-Means cluster analysis was used to test the accuracy of PXRF through statistical comparison of data acquired via laboratory and portable energy-dispersive XRF instruments. Multivariate analysis was employed to demonstrate obsidian source representation at two Classic Maya archaeological sites in southern Belize – Uxbenká and Ek Xux – and to test the validity of data obtained from a PXRF instrument in answering archaeological research questions pertaining to regional interactions between lowland Maya polities. Results suggest that portable XRF instruments produce internally consistent results. However, data acquired from a PXRF instrument are not statistically equivalent to other XRF instruments. This is to say that while PXRF is not a reliable technique, it is valid for questions pertaining to geochemical source representation.     

夏家店下层文化遗址出土铜器的矿料来源分析

为进一步了解夏家店下层文化铜器的物料信息,探讨其矿料来源,采用多接收电感耦合等离子体质谱仪(MC-ICP-MS)对4处夏家店下层文化遗址和1处高台山文化遗址出土的部分铜器进行了铅同位素比值测定,并将测定结果同辽西地区几处金属矿的铅同位素数据进行了对比。结果表明:这4处夏家店下层文化遗址出土铜器的原料可能是使用辽西当地的大井多金属矿的矿石冶炼而成,而大山前遗址出土铜器的铅料有可能来自辽宁桓仁的多金属矿,二道井子遗址所出红铜器的铜料则可能另有来源。所属高台山文化的湾柳遗址铜器的铅同位素数据具有高放射性成因铅特征,表明其与同期其他考古学文化存在某种联系。     

87Sr/86Sr: a New Discriminant for Provenancing Neolithic Porcellanite Artifacts from Ireland

Antrim porcellanite (thermally metamorphosed Tertiary laterite) was the most common raw material used in the production of stone implements during the Neolithic in Ireland and was worked at two localities in North Antrim: Tievebulliagh, near Cushendall and Brockley on Rathlin Island.Attempts have been made to provenance material from these two known sources, the most successful to date being the use of geochemical data (Sr and Yppm). Here we present a new geochemical discriminant—Sr isotopic data—which reveal that Tievebulliagh and Brockley porcellanites are distinctive. Present-day⁸⁷Sr/⁸⁶Sr ratios form two discrete groupings ranging from 0·705894±25–0·706443±24 at Tievebulliagh and 0·704088±27–0·704587±25 at Brockley. A coherent relationship between⁸⁷Sr/⁸⁶Sr and Sr (ppm) reiterates the use of Sr content as a discriminant and illustrates the geochemical variability of Sr between these two sources.Although this is a destructive technique,⁸⁷Sr/⁸⁶Sr represents the best discriminant to date for Antrim porcellanites and will enable definitive provenancing of porcellanite artifacts from Ireland with important archaeological implications.     

The children of Kaminaljuyu: Isotopic insight into diet and long distance interaction in Mesoamerica

Known for its spectacular tombs and adobe talud–tablero architecture, the highland Guatemalan city of Kaminaljuyu is key to models of long distance interaction in Mesoamerica. We use stable isotopic data from human bone, dentine and tooth enamel to reconstruct Kaminaljuyu’s dietary history. Stable carbon isotope ratios and alkaline earth ratios of enamel carbonate indicate a decline in maize consumption from Preclassic to Classic periods, perhaps due to the desiccation of Lake Miraflores, which was used to irrigate Late Preclassic fields. Stable oxygen and strontium isotope ratios in enamel shed light on the geographic origin of Early Classic skeletons, and show that the central skeletons in the tombs were local children. However, four decapitated skulls and two peripheral skeletons show enriched oxygen ratios, similar to Lowland Maya sites. Strontium isotope ratios indicate that most of these are from an area underlain by Cretaceous limestones; one is from a metamorphic region. Two individuals may have traveled to or from Central Mexico. The greater evidence for lowland individuals among the tomb skeletons implies that political connections with the Maya area were more significant to elites at Kaminaljuyu than was direct contact with Central Mexico.     

Assessing XRF for the geochemical characterization of radiolarian chert artifacts from northeastern North America

The purpose of this paper is to emphasize the benefits of adopting non-destructive energy dispersive X-ray fluorescence (ED-XRF) as a first-order technique to determine chert whole-rock geochemistry for archaeological sourcing. Chemical signatures for the Touladi and La Martre prehistoric quarries from the lower St. Lawrence and Gaspé Peninsula region of Quebec, Canada, are determined and serve as references to test the provenance of regional chert artifacts. Chert experimental flakes, created from quarry geological hand samples, are analyzed and used to validate the method. Archaeological flakes and tools recovered from three archaeological sites are analyzed and tested against quarry samples. Geochemical diagrams and Principal Component Analysis are used to establish artifact-quarry relationships. The effects of surface weathering on the geochemical analysis of archaeological chert artifacts are presented. Sample restoration and research avenues are discussed and proposed to further enhance the robustness of future chert geochemical data sets.     

A New Method For Combining Lead Isotope and Lead Abundance Data to Characterize Archaeological Copper Alloys*

We present a new methodology for interpreting lead isotope data from archaeological copper alloy objects. It is not based on the conventional isotope ratio biplots, which were originally devised to allow the calculation of the geological age of the lead mineralization, but is derived from isotope mixing models, more often used for presenting strontium isotope data. We illustrate the method by reworking published data on Sardinian Nuragic oxhide ingots and copper alloy artefacts. While we confirm the consensus assumption that the oxhide ingot fragments found on Sardinia are isotopically consistent with Cypriot copper ores (although we see no isotopic reason to favour only Apliki, as originally suggested), we also show that there is evidence for mixing between local and ingot copper in some objects, which was previously not detected. More broadly, we suspect that the apparent mismatch between some source allocations for copper drawn from isotope geochemistry and the rest of the archaeological data in some cases might be due to mixed isotopic signals being incorrectly assigned to a specific source, and suggest that the method presented here will reduce the chances of this happening.     

Romita pottery revisited: a reassessment of the provenance of ceramics from Colonial Mexico by LA-MC-ICP-MS

The origin of Romita pottery has been a controversial topic during the last three decades of Colonial Mexico archaeological studies. Lead isotopic analyses of glaze coatings of Spanish and Mexican pottery, and Romita ceramics unearthed from the archaeological site of the Metropolitan Cathedral in Mexico City provide evidence that support a Mexican origin.     

LEAD ISOTOPE APPROACH TO THE UNDERSTANDING OF EARLY JAPANESE BRONZE CULTURE

For several years, the authors have used lead isotope analysis to investigate extensively the provenance of ancient bronze or copper artifacts which had been excavated mainly from Japanese archaeological sites. The results have been published item by item in several relevant Japanese journals. This review is intended to give an account which will review the whole work relating early Japanese bronze culture to Chinese and Korean cultures through lead isotope study.     

Provenance of Early Bronze Age metal artefacts in Western Switzerland using elemental and lead isotopic compositions and their possible relation with copper minerals of the nearby Valais

Ten Early Bronze Age (BzA1, 2200–2000 BC) copper artefacts from the central Valais region from Switzerland were studied for their elemental composition and lead isotope ratios. In order to answer the archaeological question of a local copper supply, a database for copper minerals across the Valais (Switzerland) has been established. This database contains 69 data on lead isotope ratios as well as additional information on the minerals and geochemical associations for copper minerals from 38 locations in the Valais. Comparisons of the artefacts were also made with data pertaining to minerals from various deposits from Europe and Anatolia taken from the literature. The provenance of the materials is very diverse. Some of the data are compatible with the data from the copper mineral deposits of the Valais region. Moreover, three copper lunulae were identified as possibly Tuscan, which suggests contacts between Italy and the Valais region. This pattern also establishes a multiplicity of provenances for the metal and cultural influences in the Alpine environment of the Rhone Valley of Switzerland at the beginning of the Early Bronze Age.     

Andean Ores,Bronze Artifacts,and Lead Isotopes: Constraints on Metal Sources in Their Geological Context

With a focus on bronze production in the south-central Andes during the Middle Horizon, this study reports the first archaeological use of lead isotope analysis to investigate metallic ores and metal artifacts in the Andean zone of South America. Because the vast majority of metal deposits in the Andean cordillera formed in a convergent plate boundary setting, lead isotope compositions of most Andean ore sources are not unique. Lead isotope ratios of central and south-central Andean ores define four geographically distinct ore lead isotope provinces, oriented and elongated parallel or sub-parallel to the trend of the Andean cordilleras. Consequently, ore lead isotope ratios vary strongly from west to east along transects through the coast, highlands, and altiplano, but they exhibit much less variation from north to south. The strong west-to-east variation in ore lead isotope signatures allows discrimination between ore bodies, and ultimately between metal artifacts, as a function of macro-ecozone location: coast, junga-qiswa, puna, and altiplano. We present the most up-to-date database of ore lead isotope signatures for the south-central Andes including those determined for ores we sampled over an approximate 250,000-km² region within Bolivia, northern Chile, and northwest Argentina. Lead isotope signatures of Cu-As-Ni bronze artifacts from Tiwanaku (altiplano capital) and San Pedro de Atacama (desert oasis entrepôt) establish that altiplano and high sierra ore bodies provided the metal for both assemblages. Conchopata (Wari) arsenic bronze artifacts exhibit lead isotope ratios compatible with the Julcani (Huancavelica) copper sulfarsenide deposit.     

The analysis of copper artifacts of the copper inuit

Metallography and neutron activation analysis have been used to investigate copper artifacts from 19th century archaeological sites associated with the “Copper Inuit” of the west-central Canadian Arctic. A knowledge of the source of the copper from which the artifacts were manufactured - native (local) copper or European (exotic) copper - is important, for example, to studies of the effects of European contact on utilization of native copper and on the general lifestyle of the Copper Inuit. Trace element analysis by neutron activation using the SLOWPOKE reactor has allowed local native copper, from the Coppermine River and Victoria Island, NW Territories, to be clearly distinguished from 19th century European smelted copper, which was found to contain higher concentrations of arsenic, antimony, nickel and selenium. Moreover, optical and scanning electron metallography revealed significant microstructural differences between native copper and the 19th century smelted copper. As a consequence it was possible to differentiate between native copper archaeological artifacts and those produced from smelted copper.     

The history of the United States cent revealed through copper isotope fractionation

Copper isotope fractionation in United States cents traces changes in the source of copper and identifies historical events. Application of copper isotopes as a geochemical tracer requires consistent isotopic signatures of the ores and refined metals. Overlapping isotopic signatures of crushed ores, chalcocite and refined metal extracted from Morenci, Arizona indicate modern mining processes that produce distinguishable single ore deposit geochemical signatures. The coincidence of copper isotope ratios in metals and ore deposits also exists within the United States cents analyzed here. Specifically, historical records confirm two different sources for copper in cents from 1800 through 1867. The copper isotope composition of the 1828, 1830, 1836, 1838 and 1843 cents coincides with the Cornwall ores of England, and cents post 1850 (1859, 1862) correspond with the Michigan ores of the United States. Three of the thirty-six post 1867 cents measured possess fractionated copper isotope ratios and indicate the change in source of copper for the United States cent.     

Isotopic Composition of Lead in Copper Ores and a Copper Artefact from the La Profunda Mine (León,Spain)

This paper continues the characterization of the lead isotopic fingerprint of ancient copper mines in the north‐west of Spain. In this work, the lead isotopic compositions found in copper ores from the La Profunda mine are presented. Azurites and malachites sampled from this deposit were subjected to lead isotope analysis by multicollector ICP–MS. The results showed a clear radiogenic lead signature compatible with the presence of uranium‐rich minerals (such as zeunerite) in the same mining complex. Moreover, a rare copper artefact, found in the galleries of the mine during its modern exploitation, was also analysed and showed that local mineral was used for its manufacturing.     

Lead isotope and metal source of Shang bronzes: a response to Sun et al.’s comments

In this brief response to Sun et al.’s ( 2018 ) comments on our paper, we re‐emphasize that archaeological, chemical and isotopic evidence are all relevant to the discussion about the metal source of the Shang period with highly radiogenic lead isotope ratios. The southern African bronzes have much lower lead contents and quite different lead isotopic signatures than the Shang bronzes. More importantly, there was no metallurgy of any kind in southern Africa before c.200 ce , so southern Africa cannot possibly be the source of Shang bronze, which date to about 1500 to 1000 bce .