Metallurgy in Southeast Asia

Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures DOI 10.1007/978-94-007-3934-5_10178-1 # Springer Science+Business Media Dordrecht 2014

Metallurgy in Southeast Asia Thomas Oliver Pryce* French National Centre for Scientific Research, L’université Paris Ouest Nanterre La Défense, France

Situated at the eastern terminus of the mighty Himalayan range, Southeast Asia’s early metal technologies are intimately related to similar developments in neighboring Eurasian populations – namely, in present-day China and India (Fig. 1). This chapter will summarize past and current academic thinking on how regional base metal (copper, tin, lead, iron) production, exchange, and consumption was initiated and evolved from the début of the Mainland Southeast Asian (MSEA) Bronze Age through to the Historical era, c. 500 AD. The Island Southeast Asian Metal Age will be briefly treated at the end due to the significant time gap in its appearance.

The Bronze Age In the previous paragraph, I specifically avoided giving an absolute date for the MSEA Bronze Age as therein lies a controversy that has spanned almost five decades and has yet to be unanimously settled. Due to the complex mid-twentieth century political situation in MSEA, the first “modern” archaeological investigations did not take place until the mid-1960s and were concentrated in northeast Thailand (Fig. 1). The two cemetery/habitation sites in question, Ban Chiang and Non Nok Tha, furnished metal and metal-founding paraphernalia (crucibles and moulds) in contexts with claimed thermoluminescence and radiocarbon dates to the mid-fourth millennium BC (e.g., Bayard, 1972; Gorman & Charoenwongsa, 1976; Solheim, 1968). These dates were, at the time, earlier than those for the earliest metallurgy in China and were also published during the ascendancy of the New Archaeology movement, which then had a substantial focus on multicentric origins for major agricultural and technological developments. The inevitable result of this confluence of interests was the proposition that Thailand was a center for the independent invention of copper-base metallurgy, rather than having adopted and/or adapted foreign technologies (reviewed in White, 2008, p. 91). This was punchy stuff and chimed well with those advocating Southeast Asian agency after decades of colonialism, but was soon disputed by general and regional archaeologists on methodological and data-scarcity grounds (e.g., Higham, 1975; Muhly, 1981). The notion of an independent origin for regional metallurgy was dealt a decisive blow by a drastic revision of Ban Chiang’s Bronze Age layers to the early-second millennium BC (White, 1986) and the complete dismissal of Non Nok Tha’s compromised radiocarbon chronology (Spriggs, 1996–1997). Nevertheless, it is the universally academically rejected 3600 BC “independent origin” interpretation that can still be found in regional tourist guidebooks. Notwithstanding MSEA’s vast geographical size and ecological diversity, which imply that we should not necessarily expect unified and constrained regional chronological horizons, extensive fieldwork, laboratory, rhetorical, and theoretical efforts to resolve an absolute Bronze Age date continued throughout the 1990s and 2000s to the present day. The issue at stake is more than mere scholarly rectitude but concerns competing visions of Southeast Asia’s cultural trajectory and the respective roles of local agency, foreign influence, and transformative technologies in evolving

*Email: [email protected] Page 1 of 17


Fig. 1 Major regions and sites mentioned in the text

regional social stratification and political complexity. Space constraints dictate that I run the risk of reductiones ad absurdum the two principal positions, which I label the “long” and “short” chronologies for succinctness: • The “long” chronology’s chief advocate, Joyce White, places the Neolithic/Bronze Age transition c. 2000 BC (White, 2008) and sees the appearance of copper-base metallurgy in northeast Thailand (Ban Chiang) as the result of migrant metalworkers, or those trained by them, importing a complete and competent technological tradition from southwestern China, and potentially as far as the Altaï Range of western Mongolia (White & Hamilton, 2009). In White’s view the earliest MSEA copper-base metallurgy has a limited cultural impact and is not associated with increased sociopolitical complexity. The same parties also dispute the dating of MSEA’s Neolithic to the tune of at least one millennium (Higham, Guangmao, & Qiang, 2011; Rispoli, 2007). • The “short” chronology’s principal advocates, Charles Higham and Roberto Ciarla, place the Neolithic/Bronze Age transition c. 1100–1000 BC, based upon radiometric dates for Bronze Age and terminal Neolithic sites across MSEA, as well as having re-dated the Ban Chiang sequence using stratified animal and human bone samples (Higham et al., 2011; Higham, Higham, & Kijngam, 2011). Their detailed assessment of literature on the Chinese Bronze Age suggests to them a technological transmission route via southeastern China – though they do not entirely dismiss a southwesterly derivation as per White – and that the mechanism was “trade and exchange” (i.e., diffusion) rather than the long-range movement of experienced metalworkers. In the “short” chronologists’ view, the earliest MSEA metallurgy has, especially at the extensively excavated northeastern Thai cemetery and habitation site of Ban Non Wat, a huge cultural impact, with copper/bronze being used to enhance the social status of incipient political élites (Higham & Higham, 2009).

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My current position, based upon the data deployed by White, Higham, and Ciarla and noting the huge knowledge gaps in the potential transitory regions of northern Laos, Myanmar, and Vietnam, is that the balance of probabilities tilts sharply towards the “short” rather than the “long” chronology. White’s (2008) c. 2000 BC transition Ban Chiang chronology presents a very large anomaly compared to the rest of Southeast Asian Bronze Age dataset, but her suggestion of a southwestern Chinese transmission route is certainly worthy of further investigation, not least as there may have been multiple routes responsible for the appearance of metallurgy in different parts of MSEA. Aside from the strict question of dating, the metallurgical data themselves are of paramount importance. However, a comprehensive typology of Bronze Age (or Iron Age) MSEA copper-base artifacts has yet to be produced so, while various common forms of axe/adzes, bangles, rings, bells, and vessels may be recognized (e.g., Rispoli, Ciarla, & Pigott, 2013, Fig. 13), detailed technostylistic comparisons remain problematic. Likewise, while many excavated MSEA Bronze Age cemetery and habitation sites (e.g., Cambodia, Mlu Prei; Myanmar, Nyaunggan; Thailand, Ban Chiang, Ban Lum Khao, Ban Na Di, Ban Non Wat, Non Nok Tha, Non Pa Wai; Vietnam, Dong Den, Dong Dau; see Fig. 1) have furnished some evidence for secondary copper/bronze production in the form of bivalve molds, shallow-spouted crucibles, and/or hearth remains; only in a few cases (e.g., Cawte 2011; Higham & Kijngam, 1984; Vernon, 1996–1997, 1997) have these been subjected to detailed scientific study. Useful comparisons, though difficult, have been made in the highlighting of similarities with various Chinese traditions (e.g., Ciarla, 2007b; Higham, Higham, Ciarla et al., 2011; Pigott & Ciarla, 2007; White & Hamilton, 2009), as well as the striking volumetric and thermal history dissimilarity between crucibles used in MSEA secondary (refining, alloying, and melting) and primary (smelting) copper/bronze production processes (Pryce et al., 2011). Metallurgical data were certainly taken into account by the “long” and “short” model advocates discussed above, but as a predominantly extractive archaeometallurgist, I will concentrate on primary production sites and exchange networks for the remainder of this section. The study of MSEA primary metal production (mining and smelting) sites was initiated by the Thailand Archaeometallurgy Project in the early 1980s, which focused on two such loci, Phu Lon and the Khao Wong Prachan Valley, in northeastern and central Thailand, respectively (Fig. 1, Natapintu, 1988; Pigott, Weiss, & Natapintu, 1997). The Phu Lon complex, although it lies on the banks of the River Mekong, a major potential communication route for the transmission of metal technologies, did not produce any reliable Bronze Age dates and will be discussed in the following Iron Age section. However, the site of Non Pa Wai, in the Khao Wong Prachan Valley, consists of a Neolithic cemetery (c. 1800–1100 BC), overlaid by a Bronze Age (c. 1100–500 BC) cemetery and possible habitation with copper founding and limited smelting evidence, followed by a very substantial Iron Age copper smelting/founding deposit (c. 500 BC to 200 AD, Rispoli et al., 2013, Fig. 4). These dates form part of the “short” chronology argument, but the technically competent copper-base founding evidence at Non Pa Wai c. 1100 BC could support the idea of experienced migrant metalworkers, an important element of the “long” chronologists’ model (White & Hamilton, 2009). However, detailed laboratory study of predominantly Iron Age Non Pa Wai slag, mineral, and crucible samples suggests that the copper smelting technique was rudimentary, inefficient, and potentially experimental for in excess of a millennium (c. 1100 BC to 200 AD) and that they were not, as the “long” model would advocate, experienced in the complete copper/bronze production process (Pryce, Pigott, Martinón-Torres, & Rehren, 2010). By this I mean the slags’ high chemical and microstructural variability indicates that neither smelting recipes nor operating parameters were fixed, as would be expected when metalworkers were trying out new ideas or working haphazardly. It has recently been argued that some samples once thought to be intrusive in Bronze Age layers can Page 3 of 17


Fig. 2 A low-tin bronze axe with a non-local lead isotope signature excavated from a Bronze Age grave at Non Pa Wai (lh image courtesy of the Thailand Archaeometallurgy Project)

indeed be dated to the Bronze Age (Rispoli et al., 2013). These samples could not be distinguished at the time of the laboratory study (Pryce et al., 2010). Indeed, geochemical analyses by the Southeast Asian Lead Isotope Project of a Bronze Age axe from Non Pa Wai (Fig. 2) indicate that it was not produced from local copper, and its very low tin content (c. 1 wt%) probably resulted from its constituent metal having been diluted by several alloying cycles (Pryce, Brauns et al., 2011; Pryce, Pollard, Martinòn-Torres, Pigott, & Pernicka, 2011). This also seems to have been the case at Ban Non Wat, where the very earliest copper-base artifacts (“Bronze Age 1,” c. 1050–1000 BC) have a low tin content and do not match any known Southeast Asian source, whereas two unalloyed copper adze/axes and one chisel from “Bronze Age 2” (c. 1000–900 BC) burials are highly consistent with the Non Pa Wai isotopic production signature and provide a solid cross-date for early Thai copper smelting (Pryce, 2011; Pryce et al., 2014). Even putting the dating issue to one side, the laboratory identification of probable imports during the initial MSEA Bronze Age is arguably closer to the “short” model of “trade and exchange” of metal objects stimulating local primary production, rather than the migrant metalworkers importing a complete and competent metallurgical package, from whichever direction (for MSEA see Pryce et al., 2010; for Eurasia see Roberts, Thornton, & Pigott, 2009, p. 1013). It should be noted that MSEA Bronze Age metal artifacts are few in number and even fewer from sites with reliable chronological sequences. Of this limited subset, only 17 have actually been subjected to detailed technical analysis, of which six artifacts can have their raw materials attributed with reasonable confidence to a known source: the three Ban Non Wat BA2 artifacts that match the Khao Wong Prachan mentioned above, two bronze bangles, and one bronze spearhead from Upper Early Period (“Bronze Age,” Higham, Higham, Ciarla et al. 2011) Ban Chiang that are consistent with a major copper smelting center at Xepon in Laos (Fig. 1), which has so far only produced Iron Age stratified dates (see below, Pryce, Baron et al., 2014, Table 1). The small but growing collection of high-quality data for Bronze Age MSEA metallurgy, alongside fieldwork efforts to fill in the enormous lacunae in Laos and Myanmar (e.g., Pryce et al., 2013; Pryce et al., 2014), means our understanding of the region’s very earliest copper-base metal technologies is likely to improve significantly and rapidly in coming years, but I think the direction of travel is already clear – a late

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second millennium BC partial transmission of knowledge and objects via one or more southerly Chinese traditions. No MSEA Bronze Age tin production centers have yet been identified, so contemporary regional bronzes with Non Pa Wai or Xepon copper signatures may represent the import of unalloyed tin from long-distance, potentially Chinese, sources. MSEA Bronze Age bronzes typically contain low levels of lead, which probably is derived from the copper and/or tin ore minerals rather than a deliberate addition of lead metal. Correspondingly, no contemporary regional lead production centers have yet been identified despite the abundance of potential sources (for Thailand see Sitthithaworn, E. (Cartographer), 1990).

The Iron Age Conventionally defined by the appearance of iron and/or steel artifacts in archaeological contexts, though usually heralding a period of major shifts in sociopolitical complexity, the beginning of the MSEA Iron Age is dated to the fifth to fourth century BC. Before I enter into a discussion of regional iron/steel production and exchange, for which we have relatively few data, the cultural implications of the Iron Age transition can be highlighted by looking at what happens to copper/bronze consumption. Quite simply, it rockets. Gone are the days when iron/steel, as a superior alloy, was thought to displace copper/bronze. Rather, the use of copper/bronze during the MSEA Iron Age is concentrated on the decorative and ideational sphere (bells, bowls, drums, figurines, finger and toe rings, bangles, belts and ear discs), whereas utilitarian objects (adze/axes, knives, digging stick tips, ploughshares, and spearheads) are produced in iron/steel. In some instances, bimetallic objects combine the mechanical and aesthetic qualities of the two. The drastic rise in copper/bronze consumption is best seen in MSEA Iron Age cemeteries, where human burials are frequently found with literally dozens of bangles on each arm (e.g., Fig. 3). It would be impractical to wear so many bangles in life, so, as a funerary assemblage, we must remember that any social differentiation thus signaled in an individual’s death was communicated by their survivors. Nevertheless, the firm impression is given of copper/bronze being used to emphasize the personal and/or group status of a much wider proportion of the MSEA Iron Age population than was seen in the Bronze Age social aggrandisers very restricted consumption (Higham & Higham, 2009; Higham, Higham, Ciarla et al. 2011). Supply naturally following demand, Non Pa Wai’s vast Iron Age 1 and 2 (c. 500 BC to 200 AD, Rispoli et al., 2013) copper smelting deposit is up to 3 m thick over 5 ha and evidences substantial though inefficient production. Archaeometallurgists often discuss what is meant by production efficiency as a process may be optimized for fuel, mineral, or labor expenditure. Here I mean there was lots of copper left in the slag, as prills and unreacted minerals. Three kilometers away at Iron Age 2 (c. 200 BC to 200 AD, Rispoli et al., 2013), Nil Kham Haeng, a meticulously crushed industrial deposit up to 6 m deep over 4 ha, is a testimony to intensive high-labor mineral-efficient primary copper production (Pryce et al., 2010) and is replicated at numerous sites of different sizes in the environs of the Khao Wong Prachan Valley: including the Khao Sai On Mineral District, Promatin Tai, and Tha Kae (Ciarla, 2007a; Pryce et al., 2011; Rispoli et al., 2013). Likewise, 400 km north, at the aforementioned Phu Lon complex, Iron Age primary copper production of a similarly motivated ethos is indicated by the mining out of half a mountain, to the point at which it collapsed, and the fine crushing of all materials to extract the maximum possible metal (Pigott, 1984; Pigott & Natapintu, 1988; Pigott & Weisgerber, 1998; Pryce, Brauns et al., 2011). Furthermore, archaeologists working at a modern copper/gold mine, Xepon in central Laos, have identified Page 5 of 17


Fig. 3 (Left and detail) Burial 14 and (centre) Burial 69 with copper-base belts, arm bangles, finger, and toe rings at Noen-U-Loke (Courtesy of Charles Higham), (right) Burial 82 with copper-base belt and bangles (right forearm) at Ban Non Jak (Courtesy of Charles Higham, Nigel Chang, Dougald O’Reilly, and Louise Shewan)

a prehistoric copper production complex stretching over several kilometers of the Annamite mountain range, which also corresponds to a pass connecting the Mekong River Basin with coastal Vietnam (Fig. 1, Pryce, Brauns et al., 2011; Sayavongkhamdy, Chang, Viengkeo, & Cawte, 2009). Excavation has to date provided only for Iron Age (c. 200 BC to c. 200 AD) radiocarbon dates, but the absence of glass ornaments in some contexts (a typical Iron Age find class) and the lead isotope cross-dates with early Ban Chiang bronzes suggest strongly that Bronze Age production loci remain undiscovered on the vast mining concession. A detailed laboratory study is in planning, but preliminary analyses reconstruct a complete copper production sequence: mining, smelting, refining, and alloying using a broadly similar crucible type to that seen at Non Pa Wai and/or a furnace arrangement (Fig. 4, Wątroba, 2012). In addition to the primary production data, exchange patterns identified by the Southeast Asian Lead Isotope Project and a Japanese team lead by Professor Yoshimitsu Hirao (e.g., 2013) evidence a major shift in MSEA copper/bronze consumption behavior during the Iron Age. Not only are copper-base artifacts much more common on Iron Age sites – hence the regional sample population being 500+ as opposed to 17 for the Bronze Age – approximately half of the studied finds are made from leaded bronze or, less frequently, leaded copper. The addition of lead to copper or bronze reduces the liquidus (melting point), making it easier to cast larger objects with more decorative detail, which is exactly what MSEA Iron Age metalworkers needed to produce the drums, bowls, and bells for which copper/bronze was then predominantly used. However, despite the presence of numerous MSEA lead deposits, and even the identification of premodern lead mines in west-central (Glover & Sukawasana, 1990) and northern Thailand (Pigott, 1984), none has yet produced a date Page 6 of 17


Fig. 4 Copper processing crucibles from (top, Courtesy of Roberto Ciarla) Non Pa Wai (Bronze/Iron Age) and (bottom, Courtesy of Nigel Chang) Puen Baolo, Xepon

for Iron Age exploitation (Pryce 2012). Of the handful that have been characterized by lead isotope analysis (LIA), none match the archaeological artifact LIA database, so the sources of lead used during the MSEA Iron Age are currently unknown. Moreover, once copper or bronze is alloyed with lead metal, the latter’s lead isotope signature completely overwhelms the signature of the trace lead derived from the copper and/or tin ores. At present we have no idea of the sources for any raw materials for about 50 % of the MSEA Iron Age copper/bronze database. Indeed, the situation looks even worse once one taken into account the non-leaded alloys – the other c. 50 % – whose trace lead signature can theoretically, and sometimes in practice, indicate the geological region from which the copper was produced. Although LIA characterization of the three known MSEA Iron Age primary copper producing areas, the Khao Wong Prachan Valley, Phu Lon, and Xepon, has furnished very distinct signatures (Pryce, Brauns et al., 2011), only a tiny number of MSEA Iron Age finished artifacts can be reasonably attributed to those sources (Pryce, Baron et al., 2014). So what is going on? Do we just give up? No. Although MSEA’s substantial mineral wealth (Smith 2012) undoubtedly means prehistoric primary metal production centers remain to be found, the near absence of matches between regional production and consumption signatures warrants more explanatory effort:

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• First, a substantial proportion of the MSEA Iron Age nonferrous-based metal database consists of objects that are, at least stylistically, “exotic,” meaning they may well have come from outside of MSEA. Correspondingly, many of these objects, and in particular the “Indian” wrought high-tin bronze bowls and the Han Chinese leaded bronze bowls and leaded high-tin bronze mirrors, produce the most strikingly different isotopic data (Fig. 4, Pryce, Baron et al. 2014). What this patterning evidences, and is corroborated by studies of ceramics and glass (e.g., Bellina, Epinal, & Favereau, 2012; Dussubieux & Gratuze, 2010), is that as opposed to the relatively low intensity long-distance interactions of the MSEA Bronze Age, from the fourth to fifth c. BC, some regional populations were participating in highly active cultural exchange spheres linking maritime, littoral, and continental groups from the Pacific to the Mediterranean (Bellina and Glover 2004; Sherratt 2006), which foreign stimulus contributed to rapid changes in MSEA sociopolitical complexity (Fig. 5). • Second, nonferrous metal exchange studies are highly susceptible to mixing, alloying, and recycling processes. The admixture of copper metal from two different sources, e.g., the Khao Wong Prachan and Xepon, will produce a cumulative lead isotope signature directly proportional to the trace lead content of the constituent metals – i.e., Xepon lead has c. 2,000 ppm Pb as opposed to c. 200 ppm in the Khao Wong Prachan, so mixing 1 kg of Xepon copper with 1 kg of Khao Wong Prachan copper will produce 2 kg of copper whose signature will still plot close to that of Xepon. Those 2 kg of copper might then be alloyed with 300 g of tin to produce a 15 wt% Sn bronze. The trace lead content of tin ores is typically much less than that of copper ores, whose isotopic signature will thus predominate, but high-Pb tin ores do exist, and over numerous alloying cycles, the constituent tin can cause the bronze signature to drift, sometimes indicating that metal circulated for centuries between production and deposition (Bray and Pollard 2012). As mentioned above, the alloying of lead completely obliterates the copper signature. Finally, whereas some MSEA Bronze Age copper-base artifacts seem to have gone directly from the original production site to a grave without further thermal treatment, the dearth of Iron Age matches suggests copper-base metals, in ingot, scrap, and finished form, were circulated, reused, and reprocessed several times before deposition. The clustering of MSEA Iron Age data into recycling “pools” suggests that the more practical scale of metals provenancing is that of regional secondary production workshops, or foundries, which seem to have circulated materials within a geographically and/or culturally delimited sphere of end users. The metal’s movement may be explained by commercial and/or social exchange factors but in either case evidence of a dynamism of social interaction that we do not see in the MSEA Bronze Age. As for the production and exchange of tin, despite the medieval and recent historical fame of the Southeast Asian Tin Belt (e.g., Bronson, 1992; Penhallurick, 1986; Tibbetts, 1978), the metal is methodologically difficult to study due to the typical nature of its original extraction (placer mining) and it being rarely found by archaeologists in non-alloyed form (Haustein et al. 2010). To date, only one site has produced any evidence for regional Iron Age tin production, the fourth to second c. BC protocity state and river port of Khao Sam Kaeo on the Gulf of Siam coast of the upper Thai-Malay Peninsula (Fig. 1). Found during excavation and survey in 2007 and 2008, one slagged crucible fragment and one slag fragment were analyzed and discovered to contain microstructural pseudomorphs from a cassiterite cementation reaction, that is, tin oxide minerals were charged into a crucible containing molten copper or low-tin bronze, with the resulting high-tin bronze alloy then being poured into one of the hundreds of nippled molds discovered on site to produce a, presumably, relatively high added-value ingot (Murillo-Barroso, Pryce, Bellina, & Martinón-Torres, 2010; Pryce, Murillo-Barroso, Biggs, Martinón-Torres, & Bellina, in press). Much works remains to be done on this potentially very important commodity in late first millennium BC exchange networks, as indeed it does for gold and Page 8 of 17


16,00

15,95

15,90

Ban Chiang

Ban Don Tha Phet

Ban Non Wat

Cam Thuy

Dao Thinh

Doc Hong

Don Klang

Dong Xa

Gazole

Gioi Phien

Hop Minh

Khao Sam Kaeo

Kiri Wangkaram

Lang Nhon

Lang Vuc

Myo Hla

Nil Kham Haeng

Non Pa Wai

Phu Lon

Prei Khmeng

Prohear

Puen Baolo

Sasi

Savidug

Song Khoai

Thap Khe Lo

Thong Na Nguak

Tilpi

Yen Phu

Ywa Gon Gyi

15,85

Northern Vietnamese copper production

207

Pb/ 204Pb

15,80 15,75

Xepon copper production

15,70

15,65

15,60

Phu Lon copper production

15,55

Khao Wong Prachan copper production

15,50

15,45 17,0

17,5

18,0

18,5

19,0 206

19,5

20,0

20,5

21,0

Pb/ 204Pb

16,00

15,90

Nhon 15,70

Nil Kham Haeng Non Pa Wai

207

Pb/ 204Pb

15,80

Phu Lon Puen Baolo

15,60

Thong Na Nguak drums Hi-Sn bowls 15,50

Han mirrors Han bowls

15,40 17,0

17,5

18,0

18,5

19,0 206

19,5

20,0

20,5

21,0

Pb/ 204Pb

Fig. 5 (Top) 206/204Pb/207/204Pb lead isotope data bi-plot for all SEALIP samples, showing poor correlation between production and consumption signatures and (bottom) 206/204Pb/207/204Pb lead isotope data bi-plot for “exotic samples,” from left to right: leaded bronze drum from Khao Sam Kaeo (c. 400–200 BC); high-tin bronze bowl from Prohear (c. 100 BC); leaded bronze Han bowl from Cẩm Thủy (c. 2000 BP); leaded high-tin bronze Western Han mirror from Khao Sam Kaeo (Reproduced from Pryce, Baron et al. 2014)

silver, both of which appear in MSEA contexts from the fifth to fourth century BC but for which no primary production sites are known and typological data are scarce due to looting and collecting (Pryce, Bellina, & Bennett, 2008; Reinecke, Laychour, & Sonetra, 2009; Schlosser et al., 2012). Page 9 of 17


Finally, I shall attempt to put the iron into Iron Age and outline its historical importance. As per the major agricultural and technological advances of Neolithic and Bronze Age transitions, regional archaeologists usually want to know the where, when, how, and why of iron/steel metallurgy’s first appearance and subsequent development, as this can furnish evidence for the long-range social interactions that may have stimulated MSEA sociocultural economic change from the mid-first millennium BC. Unfortunately, due to a number of factors particular to iron/steel, providing answers for some of these questions is appreciably harder to do than for copper/bronze: • First, although iron’s critical role in agriculture, industry, and warfare is widely recognized, it is, like lead, generally not considered to be a “prestige” metal, like copper, gold, silver, or even tin, and, as a result, regional ferrous archaeometallurgy has long been underdeveloped. • Second, even when the will exists, iron research is complicated in a tropical region where iron/ steel artifacts are frequently so badly preserved that their form and purpose for the original consumers can often only be hazarded. Thus, at present, no comprehensive typology exists for detailed techno-stylistic comparisons of MSEA Iron Age iron/steel artifacts (as per those in copper/bronze), though localized efforts have been made (e.g., Dizon 1990; Hognan & Rutnin, 1989; Pigott & Marder, 1984; Pryce et al. 2008; Sukawasana, 1991). • Third, iron/steel exchange research is hampered by the provenance methodology being only recently developed, highly destructive, expensive, and laborious, though again preliminary studies have been successfully attempted in the region (Bennett, 1982; Biggs, Martinon-Torres, Bellina, & Pryce, 2013) and are now proving especially fruitful in Angkorian period research (Hendrickson et al., 2014). • Fourth, although nearly every MSEA Iron Age habitation site furnishes smithing slags as evidence of secondary iron/steel production (Pryce & Natapintu, 2009), only three contemporary primary (mining/smelting) production sites have thus far been identified: third to first century BC Ban Don Phlong in northeast Thailand (Fig. 1, Nitta, 1997), first to second century AD Sriksetra in central Myanmar (Fig. 1, Hudson, 2012), and early/mid-first millennium AD Sungai Batu in northeast peninsular Malaysia (Fig. 1, Chia & Mokhtar, 2011), substantially hobbling comparisons of regional technological styles. So much for the dataset’s weaknesses, what interpretations can currently be drawn and how do they help us understand the MSEA Iron Age? Given the relatively late, mid-first millennium BC, date for the appearance of iron in regional archaeological contexts and the proximity of established iron making and using cultures to the west and north, it is probable that technological transmissions from one or both of these regions can account for MSEA iron/steel metallurgy, as opposed to independent development. Of the two possible foreign sources, India has often been preferred due the début of the Iron Age, and the first appearance of MSEA iron/steel, coinciding with the first evidence for sustained contact across or around the Bay of Bengal (Bellina, 2007; cf. Bellwood, 2007; Glover, 1990; Rispoli et al., 2013). India is also reputed for its bloomery or direct iron smelting traditions (e.g., Tripathi, 2008), which is the solid-state process seen at the three known MSEA Iron Age primary production sites (Chia & Mokhtar, 2011; Hudson 2012; Nitta, 1997), whereas China is famed for its precocious development of blast or indirect iron smelting technology (Bronson 1999; Needham & Gwei-Djen, 1974; Wagner, 1993). However, it is now better understood that blast smelting was prerogative of the Chinese state and its organizational power, with bloomery smelting practiced in the hinterland (Yasuyuki, 2009). It is thus quite possible that upper MSEA, especially northern Vietnam, was subjected to Chinese ferrous technological influence, while that of India predominated in lower MSEA. Though based on a small and sometimes poorly contextualized Page 10 of 17


assemblage from peninsular Thailand (Khao Sam Kaeo and environs; see Fig. 1), the most recent study of regional prehistoric iron came to the same open-ended conclusion (Biggs et al., 2013). No smelting slag was identified at any of the sites, only smithing slags, but metallographic analyses of iron/steel artifacts indicated a range of smithing traditions, potentially corresponding to contemporary Chinese or Indian techniques though not of the same level of technical competence. Complementary chemical analyses of slag inclusions within the metal matrix also suggested a wide spectrum of raw material sources, none of which can be identified at present as the necessary geochemical production database does not exist (Biggs et al., 2013). Suffice to say, much more research needs to be done on prehistoric MSEA iron/steel, but of the Iron Age package of which ferrous metallurgy was part, the conclusion is clear: the availability of cheaper and more effective tools, alongside animal traction (buffalo), transformed the region’s agricultural and industrial capacity, whereas the abundance of iron/steel weapons suggests the metal’s martial potential was well understood and employed by the upper echelons of an increasingly ranked society to consolidate economic and political power. A catalytic and transformative technology indeed and one for which a recent wave of historical period iron-based research in Cambodia, Laos, Myanmar, and Thailand is furnishing a growing literature (Hendrickson, Hua, & Pryce, 2013; Hudson, 2006; Larp, 2008; Pryce, 2013; Pryce, Chiemsisouraj, Zeitoun, & Forestier, 2011; Pryce et al., in press; Suchitta, 1992).

The Islands, Gold and Silver Despite an earlier prehistory in which very extensive seafaring accounts for both initial human colonization and various phases of neolithicisation, Island Southeast Asia (ISEA) appears to have been ametallic until c. 200 BC (Bellwood, 2007). Then, when metals do appear, they all appear at once: copper/bronze, iron/steel, gold, and silver. As such, the period c. 200 BC to 500 AD in ISEA has been termed the “Metal Age” as opposed to the “Iron Age” that overlaps in MSEA. Notwithstanding the difference in nomenclature, the transmission mechanisms responsible for initiating these multi-metallic chronological phases are doubtless related, namely, a substantial increase in the activity of numerous interlinked cultural interaction spheres (e.g., Bellina et al., 2014; Calò, 2009; Calo et al., 2014). To date, very little prehistoric archaeometallurgical research has been conducted in ISEA, which is unfortunate given that the region was known to be a substantial producer of iron/steel and gold in historical period (Bronson, 1992; Bronson & Charoenwongsa, 1994) and even today hosts some of the world’s largest copper/gold mines. As such, no Metal Age primary metal production sites are currently known, though there is some evidence for localized foundry traditions, perhaps stimulated by MSEA imports (Calò, 2009; Calo et al., 2014). ISEA metal provenance studies have only just commenced, but copper/bronze, gold, and silver artifacts are providing tantalizing hints of contacts with the Indian subcontinent, southern China/northern MSEA, and central/southern MSEA (Calo et al., 2014; Pryce, Baron et al., 2014; Schlosser et al., 2012). Once again, much more research is needed, which, when one considers the size of some of the countries in question, i.e., Indonesia, is both daunting and exhilarating in equal measure.

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Summary Steady progress has been made on the early metallurgy of Southeast Asia since research commenced afresh in the mid-1960s. Extensive and robust data suggest that the Mainland Southeast Asian Bronze Age was initiated in the eleventh to tenth century BC by the import of copper-base metals and founding techniques from a proximal interaction front along the southern Chinese border. Although the phenomenon may not have been universal across MSEA, based heavily on evidence from Ban Non Wat in northeastern Thailand, copper-base metal consumption appears to have been appropriated by emergent political élites to enhance their social status. This demand was met locally within a very short period of time (perhaps a couple of generations) by primary copper production activity in the Khao Wong Prachan Valley in central Thailand. The MSEA Iron Age commenced in the fifth to fourth century BC and was marked metallurgically by the appearance of gold and silver ornaments and a transition to iron/steel for tools and weapons, whereas copper/bronze continued to be used for ornamental and decorative applications. Notably, the demand for copper/bronze mushrooms in an environment of increasing social stratification, which was partly met through exotic imports and partly by the huge intensification of copper production in and around the Khao Wong Prachan Valley, alongside Phu Lon in northern Thailand and Xepon in central Laos. MSEA’s iron production technologies are thought to have a foreign source but arguments for China versus India are currently inconclusive due to the dearth of sites and studies, and both regions may have contributed in any event. So far the only evidence for MSEA tin production comes from Khao Sam Kaeo in peninsular Thailand, but no lead mining or smelting site has yet furnished a prehistoric date. The Island Southeast Asian Metal Age is dated from second century BC to fifth century AD and is marked by the (seemingly) simultaneous appearance of copper/bronze, iron/steel, gold, and silver artifacts. These objects were, at least for the outset, almost certainly imports from China, India, and MSEA, as a result of much increased long-distance interaction activity. No primary production sites are currently known but local founding traditions have been identified. For both MSEA and ISEA, the vast geographical areas, often covered by thick vegetation, imply that a huge amount of work remains to be done before we have anything like a comprehensive understanding of the region’s industrial history. Nevertheless, the convergence of being an ancient communication hub with exceptional mineral wealth and diverse human ecological adaptations suggests that future research will reveal a rich vein of metallurgy running through Southeast Asia’s historical trajectory.

References Bayard, D. T. (1972). Early Thai bronze: Analysis and new dates. Science, 176(4042), 1411–1412. Bellina, B. (2007). Cultural exchange between India and Southeast Asia: Production and distribution of hard stone ornaments, VIc. BC-VIc. AD. Paris: Editions de la Maison des sciences de l’homme. Bellina, B., Epinal, G., & Favereau, A. (2012). Caractérisation préliminaire des poteries marqueurs d’échanges en Mer de Chine Méridionale à la fin de la préhistoire. Archipel, 84, 7–33. Bellina, B., & Glover, I. C. (2004). The archaeology of early contacts with India and the Mediterranean World from the fourth century BC to the fourth century AD. In I. C. Glover & P. Bellwood (Eds.), Southeast Asia, from the prehistory to history (pp. 68–88). London: Routledge/Curzon Press.

Page 12 of 17


Bellina, B., Silapanth, P., Chaisuwan, B., Thongcharoenchaikit, C., Allen, J., Bernard, V., et al. (2014). The development of coastal polities in the upper Thai-Malay Peninsula. In N. Revire & S. A. Murphy (Eds.), Before Siam. Essays in art and archaeology (pp. 69–89). Bangkok, Thailand: River Books. Bellwood, P. (2007). Prehistory of the Indo-Malaysian Archipelago (3rd [1997 text] ed.). Honolulu, HI: University of Hawaii Press. Bennett, A. (1982). Metallurgical analysis of iron artifacts from Ban Don Ta Phet, Thailand. B.A. Report, Institute of Archaeology. Biggs, L., Martinon-Torres, M., Bellina, B., & Pryce, T. O. (2013). Prehistoric iron production technologies in the Upper Thai-Malay Peninsula: Metallography and slag inclusion analyses of iron artefacts from Khao Sam Kaeo and Phu Khao Thong. Archaeological and Anthropological Sciences, 5, 311–329. Bray, P. J., & Pollard, A. M. (2012). A new interpretative approach to the chemistry of copper-alloy objects: Source, recycling and technology. Antiquity, 86, 853–867. Bronson, B. (1992). Patterns in the early Southeast Asian metals trade. In I. Glover, P. Suchitta, & J. Villiers (Eds.), Metallurgy, trade and urbanism in Early Thailand and Southeast Asia (pp. 63–114). Bangkok, Thailand: White Lotus. Bronson, B. (1999). The transition to iron in ancient China. In V. C. Pigott (Ed.), The archaeometallurgy of the Asian old world (pp. 177–193). Philadelphia: University of Pennsylvania Museum. Bronson, B., & Charoenwongsa, P. (1994). Eyewitness accounts of early mining and smelting in Southeast Asia. SPAFA Journal, 4(2), 4–17. Calò, A. (2009). The distribution of bronze drums in early Southeast Asia: Trade routes and cultural spheres. Oxford, England: Archaeopress. Calo, A., Prasetyo, B., Bellwood, P., Lankton, J. W., Pryce, T. O., Reinecke, A., et al. (2014). Sembiran and Pacung on the north coast of Bali: A strategic crossroads in early trans-Asiatic exchange. Manuscript under review. Cawte, H. (2011). XVIII the bronze casting moulds. In C. F. W. Higham & A. Kijngam (Eds.), The excavation of Ban Non Wat: The Bronze Age (pp. 463–486). Bangkok, Thailand: The Fine Arts Department. Chia, S., & Mokhtar, N. a. M. (2011). Evidence of iron production at Sungai Batu, Kedah. In S. Chia & B. W. Andaya (Eds.), Bujang Valley and early civilizations in Southeast Asia. Kuala Lumpur, Malaysia: Department of National Heritage, Ministry of Information, Communications and Culture. Ciarla, R. (2007a). A preliminary report on Lo.R.A.P. Archaeological excavations at prehistoric Khao Sai On, Lopburi Province, Central Thailand. East and West, 57, 395–401. Ciarla, R. (2007b). Rethinking Yuanlongpo: The case for technological links between the Lingnan (PRC) and central Thailand in the Bronze Age. East and West, 57, 305–328. Dizon, E. Z. (1990). Prehistoric iron-use and its technology in the Philippines. National Museum Papers, 1(2), 41–65. Dussubieux, L., & Gratuze, B. (2010). Glass in Southeast Asia. In B. Bellina, E. A. Bacus, T. O. Pryce, & J. Wisseman-Christie (Eds.), 50 years of Southeast Asian archaeology: In honor of Ian C. Glover (pp. 247–260). Bangkok, Thailand: River Books. Glover, I. C. (1990). Early trade between India and southeast Asia – a link in the development of a world trading system. University of Hull, Centre for Southeast Asian Studies. Glover, I. C., & Sukawasana, Y. (1990). Archaeometallurgical survey and excavation in Ratchaburi Province, West Thailand, March-April 1990: Report to the National Research Council of Thailand. Page 13 of 17


Gorman, C., & Charoenwongsa, P. (1976). Ban Chiang: A mosaic of impressions from the first two years. Expedition, 18(4), 14–26. Haustein, M., Gillis, C., & Pernicka, E. (2010). Tin isotopy – A new method for solving old questions. Archaeometry, 52, 816–832. Hendrickson, M., Hua, Q., & Pryce, T. O. (2013). Using in-slag charcoals as an indicator of ‘terminal’ iron production within the Angkorian period (10th to 13th c. CE) centre of Preah Khan of Kompong Svay, Cambodia. Radiocarbon, 55, 31–47. Hendrickson, M., Leroy, S., Pryce, T. O., Dillman, P., Vega, E., & Pascal. (2014). Tracking iron production systems and their impact on the expansion of the Angkorian Khmer Empire, Cambodia. Manuscript in preparation. Higham, C. F. W. (1975). Aspects of economy and ritual in prehistoric Northeast Thailand. Journal of Archaeological Science, 2, 245–288. Higham, C. F. W., Guangmao, X., & Qiang, L. (2011). The prehistory of a friction zone: First farmers and hunters-gatherers in Southeast Asia. Antiquity, 85, 529–543. Higham, C. F. W., & Higham, T. (2009). A new chronological framework for prehistoric Southeast Asia, based on a Bayesian model from Ban Non Wat. Antiquity, 82, 1–20. Higham, C. F. W., Higham, T., Ciarla, R., Douka, K., Kijngam, A., & Rispoli, F. (2011). The origins of the Bronze Age of Southeast Asia. Journal of World Prehistory, 24, 227–274. Higham, C. F. W., Higham, T. F. G., & Kijngam, A. (2011). Cutting a Gordian knot: The Bronze Age of Southeast Asia: Origins, timing and impact. Antiquity, 85, 583–598. Higham, C., & Kijngam, A. (1984). Prehistoric investigations in Northeast Thailand: Excavations at Ban Na Di, Ban Chiang Hian, Ban Muang Phruk, Non Noi and Ban Kho Noi (Vol. S 231). Oxford, England: BAR. Hirao, Y., & Ro, J.-H. (2013). Chemical composition and lead isotope ratios of bronze artifacts excavated in Cambodia and Thailand. In Y. Yasuda (Ed.), Water civilization: From Yangtze to Khmer civilizations (pp. 247–312). Tokyo: Springer. Hognan, L. M., & Rutnin, S. (1989). Metallurgical analysis of iron artefacts from Thailand. Journal of the Historical Metallurgy Society, 23, 99–107. Hudson, B. (2006). Iron in Myanmar. Enchanting Myanmar, 5, 6–9. Hudson, B. (2012). A thousand years before Bagan: Radiocarbon dates and Myanmar’s ancient Pyu cities. Paper presented at the “Early Myanmar and its Global Connections” Conference, Bagan, February 2012. Available at http://www.academia.edu/5489143/Hudson_Bob_2012_A_Thousand_Years_Before_Bagan_Radiocarbon_dates_and_Myanmars_ancient_Pyu_cities_Revision_3 Larp. (2008). Living Angkor road project phase II progressive report, October 2007–March 2008. Nakon Nayok, Thailand: Chulachomklao Royal Military Academy. Muhly, J. D. (1981). The origin of agriculture and technology – Aarhus, Denmark, November 21–25, 1978. 2. Summary – The origin of agriculture and technology – West or East-Asia. Technology and Culture, 22(1), 125–148. Murillo-Barroso, M., Pryce, T. O., Bellina, B., & Martinón-Torres, M. (2010). Khao Sam Kaeo – An archaeometallurgical crossroads for trans-Asiatic technological styles. Journal of Archaeological Science, 37, 1761–1772. Natapintu, S. (1988). Current research on ancient copper-base metallurgy in Thailand. In P. Charoenwongsa & B. Bronson (Eds.), Prehistoric studies: The Stone and Metal Ages in Thailand (pp. 107–124). Bangkok, Thailand: The Thai Antiquity Working Group. Needham, J., & Gwei-Djen, L. C. (1974). Science and civilization in China, Vol. 5, Pt. II: Chemistry and chemical technology. Spagyrical discovery and invention: Magisteries of gold and immortality. Cambridge, England: Cambridge University Press. Page 14 of 17


Nitta, E. (1997). Iron-smelting and salt-making industries in Northeast Thailand. Bulletin of the Indo-Pacific Prehistory Association, 16, 153–160. Penhallurick, R. D. (1986). Tin in antiquity. London: The Institute of Metals. Pigott, V. C. (1984). The Thailand archaeometallurgy project 1984: Survey of base metal resource exploitation in Loei Province, northeastern Thailand. South-East Asian Studies Newsletter, 17, 1–5. Pigott, V. C., & Ciarla, R. (2007). On the origins of metallurgy in prehistoric Southeast Asia: The view from Thailand. In S. L. Niece, D. Hook, & P. Craddock (Eds.), Metals and mines: Studies in archaeometallurgy (pp. 76–88). London: Archetype Publications. Pigott, V. C., & Marder, A. R. (1984). Prehistoric iron in Southeast Asia: New evidence from northeastern Thailand. In D. T. Bayard (Ed.), Southeast Asian archaeology at the XV pacific science congress (pp. 278–308). Dunedin, New Zealand: Otago University. Pigott, V. C., & Natapintu, S. (1988). Archaeological investigations into prehistoric copper production: The Thailand archaeometallurgy project, 1984–86. In R. Maddin (Ed.), The beginning of the use of metals and alloys (pp. 156–162). Cambridge, MA: M.I.T. Press. Pigott, V. C., & Weisgerber, G. (1998). Mining archaeology in geological context. The prehistoric copper mining complex at Phu Lon, Nong Khai Province, Northeast Thailand. In J. D. Muhly (Ed.), Metallurgica antiqua: In honor of Hans-Gert Bachmann and Robert Maddin (pp. 135–161). Bochum, Germany: Deutsches Bergbau-Museum Bochum. Pigott, V. C., Weiss, A., & Natapintu, S. (1997). Archaeology of copper production: Excavations in the Khao Wong Prachan Valley, Central Thailand. In R. Ciarla & F. Rispoli (Eds.), South-east Asian archaeology 1992. Proceedings of the fourth international conference of the European Association of South-east Asian Archaeologists, Rome, 28th September–4th October 1992 (pp. 119–157). Rome: Istituto Italiano per l’Africa e l’Oriente. Pryce, T. O. (2011). XIX technical analysis of Bronze Age Ban Non Wat copper-base artefacts. In C. F. W. Higham & A. Kijngam (Eds.), The excavation of Ban Non Wat: The Bronze Age (pp. 489–498). Bangkok, Thailand: The Fine Arts Department. Pryce, T. O. (2012). A flux that binds? The Southeast Asian lead isotope project. In P. Jett & J. Douglas (Eds.), Proceedings of the 5th Forbes symposium on ancient Asian bronzes (pp. 113–121). Washington, DC: Smithsonian. Pryce, T. O. (2013). Sedentism, social complexity, and metallurgy in upland Southeast Asian populations. In O. Evrard, C. Vaddhanaphuti, & D. Guillaud (Eds.), Mobility and heritage in northern Thailand and Laos: Past and present (pp. 27–45). Chiang Mai, Thailand: Chiang Mai University. Pryce, T. O., Baron, S., Bellina, B., Bellwood, P., Chang, N., Chattopadhyay, P., et al. (2014). More questions than answers: The Southeast Asian lead isotope project 2009–2012. Journal of Archaeological Science, 42, 273–294. Pryce, T. O., Bellina, B., & Bennett, A. (2008). The development of metal technologies in the Upper Thai-Malay Peninsula: Initial interpretation of the archaeometallurgical evidence from Khao Sam Kaeo. Bulletin de l’Ecole Française d’Extrême-Orient, 93, 295–316. Pryce, T. O., Bevan, A. H., Ciarla, R., Rispoli, F., Malakie, J. L., Hassett, B., et al. (2011). Intensive archaeological survey in tropical environments: Methodological and metallurgical insights from Khao Sai On, Central Thailand. Asian Perspectives, 50, 53–69. Pryce, T. O., Brauns, M., Chang, N., Pernicka, E., Pollard, M., Ramsey, C., et al. (2011). Isotopic and technological variation in prehistoric primary Southeast Asian copper production. Journal of Archaeological Science, 38, 3309–3322.

Page 15 of 17


Pryce, T. O., Chiemsisouraj, C., Zeitoun, V., & Forestier, H. (2011). An VIIIth–IXth century AD iron smelting workshop near Saphim village, Northwest Lao PDR. Historical Metallurgy, 42, 81–89. Pryce, T. O., Coupey, A.-S., Kyaw, A. A., Dussubieux, L., Favereau, A., Lucas, L., et al. (2013). The mission archéologique Française au Myanmar: Past, present and future. Antiquity, 87(338), online only. Pryce, T. O., Hendrickson, M., Phon, K., Chan, S., Charlton, M. F., Leroy, S., et al. (in press). The iron Kuay of Cambodia: Tracing the role of peripheral populations in Angkorian to Colonial Cambodia via a 1200 year old industrial landscape. Journal of Archaeological Science. Pryce, T. O., Kyaw, M. M., Coupey, A.-S., Favereau, A., Guérin, S., & Perrin, M. (2014). Retour à l’Age du Bronze -Mission Archéologique en Birmanie en 2014. Chroniques Birmanes, 27. http:// www.ambafrance-mm.org/Retour-a-l-Age-du-Bronze-Mission Pryce, T. O., Murillo-Barroso, M., Biggs, L., Martinón-Torres, M., & Bellina, B. (in press). The metallurgical industries. In B. Bellina (Ed.), Khao Sam Saeo: A late prehistoric city of the Upper Thai-Malay Peninsula. Paris: Brepols. Pryce, T. O., & Natapintu, S. (2009). Smelting iron from laterite: Technical possibility or ethnographic aberration? Asian Perspectives, 48(2), 249–264. Pryce, T. O., Pigott, V. C., Martinón-Torres, M., & Rehren, T. (2010). Prehistoric copper production and technological reproduction in the Khao Wong Prachan Valley of Central Thailand. Archaeological and Anthropological Sciences, 2, 237–264. Pryce, T. O., Pollard, M., Martinòn-Torres, M., Pigott, V. C., & Pernicka, E. (2011). Southeast Asia’s first isotopically-defined prehistoric copper production system: When did extractive metallurgy begin in the Khao Wong Prachan Valley of Central Thailand? Archaeometry, 53, 146–163. Reinecke, A., Laychour, V., & Sonetra, S. (2009). The first Golden Age of Cambodia: Excavation at Prohear. Bonn, Germany: Die Deutsche Nationalbibliothek. http://www.dainst.org/medien/de/ The_First_Golden_Age_of_Cambodia_200911.pdf Rispoli, F. (2007). The incised & impressed pottery style of mainland Southeast Asia following the paths of neolithization. East and West, 57, 235–304. Rispoli, F., Ciarla, R., & Pigott, V. C. (2013). Establishing the prehistoric cultural sequence for the Lopburi region, central Thailand. Journal of World Prehistory, 26(2), 101–171. Roberts, B. W., Thornton, C. P., & Pigott, V. C. (2009). Development of metallurgy in Eurasia. Antiquity, 83, 1012–1022. Sayavongkhamdy, T., Chang, N., Viengkeo, S., & Cawte, H. (2009). The archaeology of Sepon, Lao PDR: Archaeometallurgy, unexploded bombs & collaborations. Paper presented at the 19th Congress of the Indo-Pacific Prehistory Association in Hanoi, Vietnam, November 29–December 5, 2009. Schlosser, S., Reinecke, A., Schwab, R., Pernicka, E., Sonetra, S., & Laychour, V. (2012). Early Cambodian gold and silver from Prohear: Composition, trace elements and gilding. Journal of Archaeological Science, 39, 2877–2887. Sherratt, A. (2006). The trans-Eurasian exchange: The prehistory of Chinese relations with the West. In V. H. Mair (Ed.), Contact and exchange in the ancient world (pp. 30–61). Honolulu, HI: University of Hawaii Press. Sitthithaworn, E. (Cartographer). (1990). Metallogenic map of Thailand. Smith, S. (2012). Southeast Asian orebody maps. Retrieved April 10, 2012, from http:// bannonwatblog.squarespace.com/southeast-asian-orebody-maps/ Solheim, W. G. (1968). Early bronze in northeastern Thailand. Current Anthropology, 9(1), 59–62.

Page 16 of 17


Spriggs, M. (1996–1997). The dating of Non Nok Tha and the ‘Gakashuin factor’. In D. Bulbeck & N. Barnard (Eds.), Ancient Chinese and Southeast Asian bronze cultures (Vol. 2, pp. 941–948). Taipei, Taiwan: SMC Publishing. Suchitta, P. (1992). Early iron smelting technology in Thailand and its implications. In I. C. Glover, P. Suchitta, & J. Villiers (Eds.), Early metallurgy, trade and urban centers in Thailand and Southeast Asia (pp. 115–123). Bangkok, Thailand: White Lotus. Sukawasana, Y. (1991). A study of iron objects from Ban Nong Bua, Ratchaburi Province, Thailand. M.Sc. report, Institute of Archaeology, UCL. Tibbetts, G. R. (1978). A study of the Arabic texts containing material on South-east Asia. London: Royal Asiatic Society Books. Tripathi, V. (2008). History of iron technology in India: From beginning to pre-modern times. Princeton, NJ: Infinity Foundation. Vernon, W. (1996–1997). The crucible in copper-bronze production at prehistoric Phu Lon, Northeast Thailand: Analyses and interpretation. In D. F. Bulbeck & N. Barnard (Eds.), Ancient Chinese and Southeast Asian Bronze Age cultures (Vol. 2, pp. 809–820). Taipei, Taiwan: SMC Publishing. Vernon, W. W. (1997). Chronological variation in crucible technology at Ban Chiang: A preliminary assessment. Bulletin of the Indo-Pacific Prehistory Association, 16, 107–110. Wagner, D. B. (1993). Iron and steel in ancient China. Leiden, The Netherlands: E.J. Brill. Wątroba, E. (2012). An investigation of the metallurgical material from Puen Baolo and Thong Na Nguak, Laos. M.Sc., University College London, London. White, J. C. (1986). A revision of the chronology at Ban Chiang and its implications for the prehistory of northeast Thailand. Ph.D., University of Pennsylvania, Philadelphia. White, J. C. (2008). Dating early bronze at Ban Chiang, Thailand. In J.-P. Pautreau, A. Coupey, V. Zeitoun, & E. Rambault (Eds.), Archaeology in Southeast Asia: From homo erectus to the living traditions, choice of papers from the 11th EurASEAA conference, Bougon 2006 (pp. 91–104). Chiang-Mai, Thailand: European Association of Southeast Asian Archaeologists. White, J. C., & Hamilton, E. G. (2009). The transmission of early bronze technology to Thailand: New perspectives. Journal of World Prehistory, 22, 357–397. Yasuyuki, M. (2009). Iron production in Han and pre-Han periods in Sichuan Cheng Du Plain China. Paper presented at the poster presentation at World of Iron Conference, London, February 2009.

Page 17 of 17