Prehistoric copper production and technological reproduction in the Khao Wong Prachan Valley of Central Thailand

This paper concerns the identification and explanation of change in prehistoric extractive metallurgical behaviour in the Iron Age Khao Wong Prachan Valley of central Thailand. This metallurgical complex is amongst the largest in Eurasia and constitutes Southeast Asia's only documented pre-modern copper-smelting evidence. The two Iron Age smelting sites investigated, Non Pa Wai (NPW) and Nil Kham Haeng (NKH), provide a sequence of metallurgical consumption and production evidence from c. 500 BCE to c. 500 CE. The enormous quantity of industrial waste at these sites suggests they were probably major copper supply nodes within ancient Southeast Asian metal exchange networks. Seventy-six excavated samples of mineral, technical ceramic and slag from NPW and NKH were analysed in hand specimen, microstructurally by reflected-light microscopy and scanning electron microscopy and chemically by polarising energy-dispersive X-ray fluorescence spectrometry and scanning electron microscopy with energy-dispersive X-ray fluorescence spectrometry. The analytical data were used to generate detailed technological reconstructions of copper-smelting behaviour at the two sites, which were refined by a programme of field experimentation. Results indicate an approximately 1,000-year trend of Valley copper smelters' improving technical proficiency from what may be an experimental phase of production in the mid-first millennium BCE. This amelioration in production was accompanied by a substantial increase in the human effort of copper extraction. This shift in local ‘metallurgical ethos’ is interpreted as a response to rising regional demand for copper in late prehistory.     

Pastoralist iron production on the Laikipia Plateau, Kenya: wider implications for archaeometallurgical studies

Recent research conducted on the Laikipia Plateau in Kenya highlighted several shortfalls in the existing models for understanding and interpreting past iron production technologies. The research was undertaken in order to assess variability in past pastoralist iron production techniques – the first such archaeometallurgical exploration in the region. In all, seven furnaces and one iron production refuse area were excavated across two discrete sites separated by only 3 km: Mili Sita and Cattle Dip, both dating to the second half of the second millennium AD. The recovered archaeometallurgical materials – slag, furnace wall, and tuyères – were analysed using a combination of optical microscopy, SEM-EDS and ED-XRF.The results revealed that the technologies in question were complex and sophisticated, and their reconstruction and interpretation required some special considerations. The exploitation of titania-rich black sand was observed to bear a major influence on the resulting slag compositions at both sites, and use of these specific materials resulted in consistently efficient smelting episodes, demonstrating the technical competence and skill of the past smelters. However, although the slag compositions and microstructures of all the samples were markedly similar between the two sites, striking stylistic variation was apparent in the furnace design. This raised questions not only about the organisation and identity of the smelters who were working in this area at this time, but also of the reliability of assuming that similar slag compositions – peculiar as these might be – reflect similar technological (or sociotechnical) systems (cf. Pfaffenberger, 1992). A further problem encountered was that the consequently ulvite-rich slag was comprised of five, not three, major constituents – titania and lime in addition to iron oxide, alumina and silica. This meant that the operating parameters of these smelting episodes could not be easily interpreted using the usual models, which tend to be based around the assumption of fayalitic slag.As such, this paper will discuss to what extent consistency in technological style, in a broad, sociocultural sense, can be inferred through slag analysis, as well as the need for the formulation of wider reaching models that encompass the full scope of technical variation in iron production.     

Khao Sam Kaeo – an archaeometallurgical crossroads for trans-asiatic technological traditions

Recent archaeological investigations at Khao Sam Kaeo, on the Upper Thai-Malay Peninsula, have furnished evidence for a mid/late 1st millennium BCE cultural exchange network stretching from the Indian subcontinent to Taiwan. Typological, compositional and technological study of Khao Sam Kaeo's copper-base artefacts has identified three distinct copper-alloy metallurgical traditions, with reasonable analogies in South Asian, Vietnamese, and Western Han material culture. Furthermore, analyses of technical ceramic and slag suggest that Khao Sam Kaeo metalworkers may have been using a cassiterite cementation process to produce high-tin bronze ingots for export or onsite casting/forging. Not only would this industry constitute the earliest evidence for the exploitation of Peninsula tin resources, but we also offer a speculative argument for the source of Khao Sam Kaeo's copper-base production technology.     

Slag inclusions in iron objects and the quest for provenance: an experiment and a case study

Slag inclusions are found within most archaeological bloomery iron artefacts and are remainders of slag created during the smelting and smithing processes. Although they are widely believed to provide data with the potential for provenancing iron artefacts, previous slag inclusion studies have mostly proven inconclusive. The main aim of the work reported here is to analyse experimental smelting and smithing assemblages (including ore, furnace lining, fuel and slag), to compare these to slag inclusions in the resulting bloom and worked objects, and then explore the relationships between ore, slag and slag inclusions. This study has revealed that the composition of slag inclusions most closely relates to the smelting slag produced, whereas provenance to a specific ore would be difficult due to the chemical variability derived from furnace lining, fuel and any fluxes used. Some compounds in the slag inclusions are particularly affected during smithing of the artefact, i.e. those present in the sand flux and fuel used. However, trends are observed in the K₂O/MgO, MnO/SiO₂, Al₂O₃/SiO₂, Al₂O₃/MgO, Al₂O₃/K₂O and Al₂O₃/CaO ratios that allow comparison between slag inclusions and smelting slag in these experiments, and may therefore be used during other provenancing attempts. The knowledge gained from the experimental assemblages was subsequently applied to an archaeological case study, examining objects from the 900 Cal BC smithing site of Tel Beth-Shemesh, Israel and the 930 Cal BC smelting site of Tell Hammeh, Jordan. The analyses suggest that none of the artefacts examined derived from the Hammeh smelting system.     

Slag as evidence for early iron production in arctic Norway

Physical, structural and chemical analyses were made on slag remains obtained from three sites in Iron Age arctic Norway. Scanning electron microscopy and x‐ray microanalysis were employed to confirm that the slag can only be a result of iron production. Although a distinction between slag produced by smithing and smelting proved difficult, consideration of the processes and the resources available support the assumption that both were practiced at the sites. The results provide firm evidence of iron production in the region of Norway north of the 69th parallel, by at least the sixth century AD.     

Isotopic and technological variation in prehistoric Southeast Asian primary copper production

The ‘Southeast Asian Lead Isotope Project’ (SEALIP) is intended to provide reliable geochemical proxies for late prehistoric through early historic (2nd/1st millennium BCE and 1st millennium CE) local, regional, and inter-regional social interactions, in an archaeological arena lacking established ceramic typologies with which to cross modern national boundaries. We present lead isotope characterisations of the three currently known Southeast Asian prehistoric primary (mining/smelting) copper production centres: Phu Lon and the Khao Wong Prachan Valley in Thailand, and the recently discovered Xepon complex in Laos. Kernel Density Estimation shows that these production centres can be clearly distinguished isotopically, as such fulfilling the core tenet of the ‘Provenance Hypothesis’ (Wilson and Pollard, 2001: 508) and permitting SEALIP to proceed as a research programme tracing regional copper/bronze/lead exchange and provenance patterning. In addition we provide a provisional technological reconstruction of copper smelting processes at Phu Lon to complement our more established understanding of the Khao Wong Prachan Valley. Combined lead isotope and technological datasets allow us to tentatively identify trends in the evolution of Southeast Asian metal technologies and of regional social perceptions of metal exchange.     

The technology of tin smelting in the Rooiberg Valley,Limpopo Province,South Africa,ca. 1650–1850 CE

A substantial indigenous tin-smelting industry arose in the Rooiberg valley of northern South Africa in the second millennium CE. This study concentrates upon tin-smelting slags and refractory ceramics from two archaeological sites that date between ca. 1650 CE and ca. 1850 CE. These were studied by optical and electron microscopy, wavelength-dispersive x-ray fluorescence (WD-XRF), inductively-coupled plasma mass spectrometry (ICP-MS), and electron microprobe (EMPA). The slags are predominantly glassy; high SnO and relatively low SiO₂ contents indicate that tin is a major glass-forming element. Comparison of slag chemistries with the mineralogy of ore deposits and host rocks shows that alluvial cassiterite was used at one of the sites, while cassiterite from hard-rock mining was smelted at the other site. Since few preindustrial tin slags have been studied, we compare our findings to other published examples, mostly from southwest England.     

SOUTHEAST ASIA'S FIRST ISOTOPICALLY DEFINED PREHISTORIC COPPER PRODUCTION SYSTEM: WHEN DID EXTRACTIVE METALLURGY BEGIN IN THE KHAO WONG PRACHAN VALLEY OF CENTRAL THAILAND?

Southeast Asian metallurgical developments have been a focus of international academic interest since Solheim (1968 ) and Bayard (1972 ) first published bronze artefacts in claimed early/middle third millennium bce contexts from northeastern Thailand, igniting a regional ‘origins’ of metallurgy debate that has smouldered for 40 years (e.g., White and Hamilton 2009 , Higham in press ). In this paper, we present the results of a lead isotope pilot study centred on the Khao Wong Prachan Valley of central Thailand—currently Southeast Asia's only documented prehistoric copper smelting locale. These preliminary data indicate that our ongoing regional metal exchange research programme may be able to elucidate interaction networks between copper‐producing and ‐consuming societies within and beyond Southeast Asia from c. 2000 bce to c. 500 ce . Furthermore, we are able to offer tentative evidence relevant to White and Hamilton's (2009 ) ‘Rapid Eurasian Technological Expansion Model’ for the Sino‐Siberian derivation of regional metal technologies around the turn of the third/second millennium bce .     

Direct detection of Southeast Asian smelting sites by ASTER remote sensing imagery: technical issues and future perspectives

Satellite-based multi-spectral remote sensing data were used in an attempt to identify control signatures for known prehistoric copper smelting sites in Thailand. It had been hoped that these characteristic signals could then be used as a reference for the detection of unknown Southeast Asian metal production sites, with the overall intention of strengthening the evidence base for early technological interactions with China and India. Regrettably, control signatures were not identified from the ASTER data due to issues of scale, chemistry, and vegetation, but we are able to offer reasons for this setback that might lead other scholars to develop successful applications of this methodology in more amenable (non-tropical) environments. Combined with ground truthing, intensive survey, excavation, and the technological analysis of metallurgical assemblages, this potentially useful and cost effective approach could lead to improved data density for the metal technology transmission discussions currently spanning Eurasia.     

Large-scale 2nd to 3rd century AD bloomery iron smelting in Korea

Iron production in Korea has traditionally been seen in the shadow of developments in cast iron technology in China, with limited indication for a northern influence via Russia’s Maritime Province. The possibility of the existence of bloomery iron production in ancient Korea has been little explored, and relevant discussion is fraught with speculations based primarily on the early use of cast iron. The recent excavation of a site in South Korea recovered substantial amounts of slag providing direct evidence of bloomery smelting. The accelerator mass spectrometric dating of burnt wood from inside one of the slag pieces showed that the site was in use in the early 3rd century AD or earlier, which is in agreement with the assessment based on ceramic typology. The traits of a bloomery process evident in the slags’ microstructure, shape, composition and excavation context are discussed along with the implications for historical iron technology in Korea, where cast iron and the influence from China have been overly emphasised.     

“中国西南与东南亚地区冶金技术的起源与传播暨临邛冶铁实验考古”国际学术研讨会综述

2019年11月,"中国西南与东南亚冶金技术的起源与传播暨临邛冶铁实验考古"国际学术研讨会在四川邛崃市召开。来自海内外的百余位学者,就中国西北与西南、中亚、东南亚地区冶金技术的起源与传播进行深入探讨,并在临邛汉代冶铁实验考古现场就汉代冶铁和炒钢的技术与工艺、考古遗迹与各个生产环节的对应关系、出土冶铸遗物的科技检测分析等问题展开讨论。与会代表一致认为,研讨会的召开不仅展示了亚洲大陆冶金考古的新发现和新成果,临邛冶铁实验考古也为今后冶金考古研究提供了新的思路和有效借鉴。     

Variability in single smelting episodes – a pilot study using iron slag from Uganda

Most archaeometallurgical studies of iron smelting are based on the analyses of slag fragments randomly selected from slag deposits, and assume that these samples are representative of the typical smelting conditions of the given context. However, little archaeometallurgical research has been published to explore the variability in slag composition within a single smelt, or between individual smelts at the same production site. The material used in this pilot study originates from two iron smelting sites identified in the Buganda Kingdom, Uganda, dated to the 18th and 19th centuries AD. The remains represent evidence of the industrial scale iron production that supported the growth and power of the kingdom. The slag survives in large clusters of complete blocks, in some cases weighing over 100 kg, each resulting from a single smelting episode in a pit furnace. A multi-sample analytical approach has allowed an insight into the compositional diversity within the slag from single smelting events, reflecting changing parameters in the smelting systems. The internal variation of the slag blocks is subsequently compared within and between sites, to address issues of standardisation and to differentiate two technological traditions that would appear very similar at the macroscopic level. On this basis, some sampling recommendations are made for future slag block studies.     

Investigating the production provenance of iron artifacts with multivariate methods

The quest for suitable data, data treatments and statistical methods for identifying the provenance of iron artifacts has led to a variety of analytical strategies. Researchers working on the problem have been slow to develop or adopt the use of multivariate statistical techniques, despite their successful implementation in other archaeomaterials sourcing frameworks. This paper explores the analytical potential of a comprehensive multivariate statistical strategy for identifying the primary production origins of bloomery iron artifacts using bulk chemical analyses of bloomery smelting slag and slag inclusions in iron artifacts. This strategy includes a multivariate model for identifying distinct slag inclusion types introduced during smelting and refining. Principal component analysis and linear discriminant analysis are then applied to smelting slag training sets to create multivariate provenance fields, the chemical distributions of which are defined by kernel density estimation. Single and multi-group evaluation methods are examined. Appropriate data transformations are discussed to facilitate the projection of the chemistry of “unknown” slag inclusions into the multidimensional space generated by the smelting slag groups of known provenance. The efficacy of this strategy is demonstrated through its application to a previously examined data set derived from three iron production experiments and a published archaeological example. Results indicate that an appropriately designed multivariate strategy can be an effective tool for evaluating provenance hypotheses for bloomery iron artifacts.     

Field anthropology: application to burial contexts in prehistoric Southeast Asia

The context of burials in archaeological sites, that is whether the body was inhumed, wrapped, or in a coffin, is an aspect of mortuary ritual that has been missing from English-language publications on the subject. This is despite the development and use in France over at least the last two decades of methods of determining the context under the rubric ‘l'Anthropologie de Terrain’, or Field Anthropology. This paper briefly reviews the methods and applies them to prehistoric burial samples from two sites in Southeast Asia. This shows that burials at the Bronze Age site of Ban Lum Khao were either in coffins or wrapped. The practice of coffin burial appears to have been abandoned later, as all burials at the nearby Iron Age site of Noen U-Loke were wrapped.     

BIMSTEC and emerging patterns of Asian regional and interregional cooperation

The first phase of India's Look East Policy in 1991 was exploratory in nature and tinged with more idealism and optimism to break out of the South Asian region which was stagnating in economic growth. The second phase of India's Look East policy took stock of the Asian Financial Crisis of 1997 to 1998 and China's growing linkages with the Southeast Asian region. In 1997, mainly through the diligence of Thailand, a new grouping that could act as a bridge between Southeast and South Asia was established called BIMSTEC. The objective of the paper will be to argue that BIMSTEC balances India's engagement with Southeast and South Asia but it also counters China's growing influence among ASEAN members, in particular Myanmar. Thailand is the driving force behind BIMSTEC activities as this would enhance its trade hub status and engagement policy with Cambodia, Myanmar, Laos and Vietnam (CMLV) states.     

Fuelwood collection as daily practice: a wood charcoal study for the colonial period North Carolina Piedmont

ABSTRACT

European colonization brought innumerable changes and choices to Native groups across the Southeast. Scholars continue to examine the various ways communities navigated these disruptions. Studying the remains of daily practice offers a window into how communities negotiated continuity and change. Wood charcoal, representing the remains of daily fires, provides an important, but underutilized, method for examining people’s daily routines and interactions with their surrounding landscapes. This paper examines wood charcoal assemblages from several sites in the North Carolina Piedmont that span the precontact to early colonial periods (AD 1400–1705). Fuelwood collection models are used to consider the environments, practices, and preferences that influenced the composition of wood charcoal assemblages. Comparison of these datasets shows a consistent significant pattern of high-quality fuelwood selection with additional patterns potentially related to long-term use of the same environment and factors related to colonialism. Altogether, these patterns suggest continuity of some daily practices despite disruptions to other aspects of life.     

Sewn Boats of Southeast Asia: the stitched‐plank and lashed‐lug tradition

This article updates research into the sewn‐boat traditions of Southeast Asia with recent finds that provide evidence of the transition from stitched planks with lashed‐lug frames to planks fastened with dowels and locked dowels alongside lashed‐lug frames. The differences between Southeast Asian, East Asian, and Indo‐Arabic boatbuilding are discussed and the meaning of anomalies, such as the Maldivian dhonis, examined. Considering the known history of trade and exchange throughout the South China Sea and the Indian Ocean, the lack of hybridization between boatbuilding traditions is noted.     

Establishing the Prehistoric Cultural Sequence for the Lopburi Region, Central Thailand

This study comprises the first archaeologically-defined chronological and cultural sequence for central Thailand. Based on collaborative research between the Thai–Italian Lopburi Regional Archaeological Project and the Thai–American Thailand Archaeometallurgy Project, the results of excavations at seven pre- and protohistoric sites that witnessed three millennia of local cultural development, from the early second millennium BC onward, are synthesized herein. This study fills a significant gap in Thailand’s prehistory, also identifying important cultural interactions ranging into southern China and Vietnam that led to the formation during the second millennium BC of a ‘Southeast Asian Interaction Sphere’. This interaction sphere, at the close of the second millennium BC, facilitated the transmission of the knowledge of copper-base metallurgy from southern China into Thailand, where it reached the communities of the Lopburi Region who took advantage of their ore-rich environment. At the end of the first millennium BC, strong South Asian contacts emerge in Southeast Asia. Among this study’s salient contributions is the characterization of these critical prehistoric antecedents, which culminated in a process of localization of exogenous elements, usually termed ‘Indianization’. The impact of this dynamic process was initially felt in central Thailand in the late first millennium BC, leading over time to the rise there, by the mid first millennium AD, of one of Southeast Asia’s first ‘state-like’ entities.     

The Transition to History in Southeast Asia: An Introduction

Studies of the transition from prehistory to history in Southeast Asia have traditionally relied primarily on documentary sources, which tend to emphasize foreign influences, rather than on the archaeological record, which suggests a series of indigenous developments. The papers in this journal issue and the next discuss strategies for using both documentary and archaeological evidence to study the transition to history and the emergence of early states in the region. These papers investigate how political units were structured and integrated in Cambodia, Thailand, Malaysia, the Philippines, and South China, and illustrate how historical and archaeological data can cross-check each other to inform on Southeast Asian sociopolitical and economic developments during the early historic period.     

GLASS TRADE BEADS FROM THE ENGLISH COLONIAL PERIOD IN THE SOUTHEAST,CA. A.D. 1607–1783

Abstract

The study of glass trade beads has contributed much to our chronological understanding of the colonial period in the Eastern Woodlands of North America. Indeed, this class of artifact has allowed archaeologists to identify and conduct research at important archaeological sites that never appeared in the European historical record. In the Southeast, the best chronological resolution established by current bead chronologies relates either to sixteenth- to mid-seventeenthcentury Spanish-traded bead assemblages or eighteenthcentury French-traded bead assemblages. There is a conspicuous gap, however, in glass bead chronologies associated with the seventeenth- and eighteenth-century English-Indian trade in the Southeast. In this paper, I address this gap by characterizing a large sample of trade beads (n = 35,309) found in individual mortuary assemblages recovered from a number of Southeastern Indian sites. This is the first time a regional synthesis of this scale has been conducted for the English colonial period in the Southeast. In order to begin to refine the bead chronology of this period, I also present the results of a quantitative seriation (using a technique known as correspondence analysis) of the same mortuary assemblages. While the results of this exploratory technique represent a preliminary stage in this process, they nevertheless identify a number of temporal trends that can be used to derive occupation date estimates for sites spanning the English colonial period in the Southeast (ca. 1607–1783).