No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Geologic provenience analysis of agate and carnelian beads using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS): A case study from Iron Age Cambodia and Thailand
Abstract
Agate and carnelian beads, imported from South Asia, were widely exchanged in Southeast Asia during the Iron Age period (500 BCE–500 CE). Recent studies have identified changes in bead types and manufacturing methods over time, as well as evidence for possible local production. In order to understand the broader implications of these developments, geochemical analysis using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was undertaken on 73 beads from 10 Iron Age sites in Cambodia and Thailand and 64 geologic samples from four sites in India, Iran, and Thailand. The results show that many of the beads were produced from raw material derived from the Deccan Traps, India and that there is not yet strong evidence for bead production using a Southeast Asian source. Secondly, we find that there is not yet clear evidence for a change in the different geologic sources used to produce beads over time. This study adds to the growing body of literature highlighting the utility of LA-ICP-MS in differentiating and assigning provenience to agate/carnelian and other silicates.
... Compositional analysis of the glass beads in particular has enabled us to identify multiple glass bead types and link PTT to several different manufacturing and exchange networks (Carter et al. 2022;Lertcharnrit and Carter 2010). Analysis of the agate and carnelian beads has provided more general associations with Indian raw material sources and regional exchange networks focused on the Mekong Delta and South China Sea (Carter 2015;Carter and Dussubieux 2016;Carter et al. 2021). ...
... Glass compositions point toward the importation of at least two kinds of glass (i.e., potash and high-alumina mineral soda glass) that were then worked on site (Dussubieux and Bellina 2017). Analysis of both finished and unfinished agate and carnelian beads also shows compositional similarities to raw material sources in the Deccan Traps (Carter and Dussubieux 2016). ...
... The three most common glass compositions were potash glass, high-alumina mineral soda glass, and mineral soda glass with varying amounts of lime and alumina (Carter et al. 2022). Beads made from these recipes circulated widely across Southeast Asia, although potash glass and high alumina mineral soda glass often circulated on different glass networks or over different time periods (Carter 2015;Lankton and Dussubieux 2006); finding both types at Phromtin Tai is therefore noteworthy (Carter 2016;Carter et al. 2022). In addition to these glass types, some unusual beads were found that point toward early longer-distance, coastal trade networks (Table 1). ...
The multi-component site of Phromtin Tai, Thailand is notable for its long occupation from the Late Bronze Age (ca. 700–500 b.c.e.) through early historic periods (ca. c.e. 500–900). Multiple field seasons of excavation in burial and habitation areas at the site have recovered a large number of glass and stone beads. Here we present the study of 57 stone beads from the site using qualitative and quantitative methods that demonstrate the presence of multiple stone ornament workshop traditions. Examination of perforations from beads and pendants made from regionally available raw materials of marble, nephrite, serpentine, and other undetermined stone have identified the use of metal drills with abrasives and diamond drills. These drilling techniques along with the distinctive shapes of some finely made beads, as well as the reworking of older broken beads suggests the presence of different scales and organization of local production in Southeast Asia. The different shapes and production processes of carnelian and banded agate beads also may represent various workshop traditions. Some of these latter beads may have originated in South Asia, while others may have been made in different regions of Southeast Asia. This study demonstrates that careful examination of ornament production techniques, and especially bead perforation technology, can be used to identify the presence of different workshop traditions allowing for more fine-grained consideration of inter- and intra-regional bead exchange networks in Southeast Asia. The presence of many semi-precious stone beads of different materials and having morphologically and technologically distinct features at Phromtin Tai demonstrate the active consumption of the beads by social elites at the site. These diversified and exotic status markers represent an intensification and acceleration of the economy and social complexity at Phromtin Tai.
... Basic measurements and photographic documentation at low and high magnification were carried out to define the overall characteristics of bead shape, size, and manufacturing technique. The chemical composition of each bead, as well as selected samples of chalcedony and carnelian raw materials, was analyzed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for sourcing the beads to specific geological resource areas (Carter and Dussubieux 2016;Law et al. 2013). Although additional geological source samples are needed from other regions of Mongolia and adjacent regions (especially from Gansu and Inner Mongolia, China), the preliminary results suggest that most of the beads were made using locally available carnelian resources. ...
... This variation permits the geologic sources of microcrystalline artifacts, like the carnelian beads examined in this study, to be identified with a high degree of confidence. Two analytical techniques that have been demonstrated to work well for sourcing such artifacts are instrumental neutron activation analysis (INAA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) (Carter and Dussubieux 2016;Law et al. 2013). The carnelian beads in this study were analyzed with the latter technique because it is just as accurate, less costly, and, most importantly, substantially less destructive than the former one. ...
... Over the past decade, numerous scholars have been working to assemble an extensive database of samples from geologic occurrences of agate/carnelian. To date, LA-ICP-MS has been used to produce elemental data for artifacts and raw material sources from north-eastern Africa, Arabia, West Asia, Eurasia, South Asia, as well as selected sites in East and Southeast Asia (Carter and Dussubieux 2016;Law et al. 2013). Although the full geologic database is not yet published, elemental data from pertinent sources will be provided when the final stage of analysis is discussed below. ...
The technological, stylistic, and chemical analyses of carnelian beads from archaeological sites in Mongolia provide evidence for local production and use of carnelian beads during the Late Bronze Age (c. 1400–1000 BCE) and Early Iron Age (1000–300 BCE) through the Xiongnu period (c. 250/200 BCE–CE 150). Beads dating to the historical Mongol Empire (c. twelfth to fourteenth centuries CE) demonstrate expanding trade networks that link eastern Eurasia to South Asia and beyond. Use-wear study of the exterior surfaces and interior drill holes demonstrates that carnelian beads were used and curated for many generations before being included in burials. These findings provide new insight into the daily life of ancient pastoral communities of the Mongolian Gobi Desert.
... Carnelian and rock crystal beads are shaped, spherical or faceted: termed bi-conical, bitronconical, pear-shaped, lozenge, faceted tabular according the classification by Beck [29] and taken up by Dubin [30]. Carnelian and agate beads were produced in India and Pakistan and traded very early across the Indian Ocean [31][32][33][34][35][36][37]. According to Rasoarifetra, worked patterns [18] including the faceted type are characteristic of the production at the Indian city of Cambay [9,[31][32][33][34][35][36][37], the facets giving the stone a particular sparkle. ...
... Carnelian and agate beads were produced in India and Pakistan and traded very early across the Indian Ocean [31][32][33][34][35][36][37]. According to Rasoarifetra, worked patterns [18] including the faceted type are characteristic of the production at the Indian city of Cambay [9,[31][32][33][34][35][36][37], the facets giving the stone a particular sparkle. In general, carnelians have six facets while clear quartz has eight. ...
... Carnelian gems have been used since antiquity [56,[60][61][62][63] and sources are rather well documented for the Mediterranean world [60] and for India [1,2,[32][33][34][35][36]. The moganite peak has not been reported previously. ...
In the late 19th century, ancient tombs were discovered near the village of Vohemar at the northeastern point of Madagascar, and subsequent excavations during the French period (1896–1945) revealed the presence of a major necropolis active from ~13th to 18th centuries. Some artefacts (Chinese ceramic shards and glass trade beads) recovered from these ex-cavations was sent to France and now in part belong to the collection of the Musée d’Histoire Naturelle, Nimes. Carnelian and glass trade beads were analyzed with a mobile Raman spectrometer, which identified different materials (soda-lime glass, quartz/moganite, carnel-ian/citrine, chalcedony) and coloring agents (Naples yellow, cassiterite, amber chromophore, transition metal ions, etc.). The results are compared with those obtained on beads excavated at different sites of Southern Africa and at Mayotte Island, and it appears that (most of) the beads come from southern Asia and Europe. The results confirmed the role that northern Madagascar played within the maritime networks of the Western Indian Ocean during the 15th–16th century.
... Carnelian sources are primarily known from the Indian sub-continent and Mainland Southeast Asia, namely Thailand (Carter and Dussubieux, 2016;Law et al., 2013;Theunissen et al., 2000). Most of the important carnelian sources are located in the Indian sub-continent, where carnelian is extracted from mines, such as Gujarat (the largest carnelian source worldwide) on the Deccan Plateau or Ratanpur in the Rajpipla State, or collected in pebble form from secondary river deposits (Inizan, 2000;Brunet, 2009;Ludvik et al., 2015;Carter and Dussubieux, 2016;De Waele and Haerinck, 2006). ...
... Carnelian sources are primarily known from the Indian sub-continent and Mainland Southeast Asia, namely Thailand (Carter and Dussubieux, 2016;Law et al., 2013;Theunissen et al., 2000). Most of the important carnelian sources are located in the Indian sub-continent, where carnelian is extracted from mines, such as Gujarat (the largest carnelian source worldwide) on the Deccan Plateau or Ratanpur in the Rajpipla State, or collected in pebble form from secondary river deposits (Inizan, 2000;Brunet, 2009;Ludvik et al., 2015;Carter and Dussubieux, 2016;De Waele and Haerinck, 2006). Elsewhere in Asia, carnelian can be found in southern Uzbekistan, southwestern Afghanistan (Mackay, 1933;Beale, 1973;De Waele and Haerinck, 2006) and Iran, where carnelian is both present near Shahr-i Sokhta in the Helmand Basin and on the Bushehr peninsula (De Waele and Haerinck, 2006;Inizan, 1999). ...
... Previous analytical research successful in discriminating between carnelian sources, includes Proton Induced X-Ray Analysis and Proton Induced Gamma Ray Analysis (PIXE/PIGME) (Theunissen et al., 2000;Theunissen, 2003), Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) (Insoll et al., 2004;Carter and Dussubieux, 2016), and Neutron Activation Analysis (INAA) (Law et al., 2013). These studies have concentrated on material from India, South Asia and Africa exclusively and to date no analytical work has been conducted on carnelian sources from elsewhere in the circum-Mediterranean region to our knowledge. ...
This paper presents the results of the compositional analysis conducted on carnelian beads from Aceramic Neolithic sites on the island of Cyprus. Carnelian is a rare raw material with alleged geological sources in the broader eastern Mediterranean–western Asia region. Most of these sources remain little explored and no detailed data concerning their geochemical signatures and elemental composition are available. Carnelian, albeit an exogenous material, is found in small quantities in lithic assemblages from Cypriot sites dating to 8500–5200 Cal BCE. The paper discusses these occurrences and uses non-destructive pXRF technology to (a) attempt to identify distinct geochemical groups (i.e. exploited sources) within these assemblages, and (b) use this information to infer the role of Cyprus within the broader eastern Mediterranean social landscape and exchange networks of the Early Holocene. Our analyses suggest multiple origins for the carnelian raw material and, more significantly, demonstrate that occasionally other materials, visually indistinguishable from carnelian, were used in bead manufacture. We consider the symbolic role of these raw material choices and propose that these early island communities engaged in a system of linked values with their mainland counterparts dependent on the materials exchanged objects were made of.
... LA-ICP-MS was chosen over other analytical methods as this technology "is generally highly sensitive and can achieve high-precision results for trace elements, [and] has been widely used to trace the provenance of ancient stone artifacts for reconstructing patterns of interaction" (Ma et al., 2011:890). Our methodology followed that of Dussubieux et al. (2016) and Carter and Dussubieux (2016). Analyses were conducted at the TFM's EAF using a Thermo ICAP-Q ICP-MS connected to a New Wave UP213 laser for direct introduction of solid samples. ...
... LA-ICP-MS was chosen over other analytical methods as this technology "is generally highly sensitive and can achieve high-precision results for trace elements, [and] has been widely used to trace the provenance of ancient stone artifacts for reconstructing patterns of interaction" (Ma et al., 2011:890). Our methodology followed that of Dussubieux et al. (2016) and Carter and Dussubieux (2016). Analyses were conducted at the TFM's EAF using a Thermo ICAP-Q ICP-MS connected to a New Wave UP213 laser for direct introduction of solid samples. ...
... The parameters of the ICP-MS are optimized to ensure a stable signal with a maximum intensity over the full range of elemental masses and to minimize oxides and double ionized species formation (XO + /X + and X ++ /X + < 1 to 2%). For that purpose, the flow of argon, the radio-frequency power, the torch position, the mirror, lenses, and detector voltages are adjusted using an auto-optimization procedure (see Dussubieux et al., 2016 for further discussion regarding ICP-MS operating procedures). ...
Many publications document Easter Island's famous ahu (platform), moai (statue), pukao (topknot), and almost millennium-long culture. Yet, little investigation has been dedicated to basalt resources, artifacts, and their geochemistry. As part of the Rapa Nui Geochemical Project (2014-2017), we conducted comprehensive fieldwork , material culture and archaeometric analyses focused on Easter Island's archaeological basalt industries. Our results highlight how the prehistoric Rapanui were sophisticated Polynesian stone workers who developed multiple tool reduction sequences for several types of basaltic material, creating unique anthropogenic landscapes in the process. Using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) of geological source material from 31 quarries and 61 artifacts from the Sebastián Englert Anthropology Museum, we argue that similar to other culturally valuable stone (i.e. obsidian, scoria, and tuff), there was communal access to and use of Rapa Nui's basalt resources. In turn, prehistoric communal access to stone hints at patterns of sociopolitical and economic interaction, including cultural connectivity on this eastern Polynesian outpost. Thus, our empirically derived archaeological conclusion casts doubt on sociopolitical and economic interpretations proposed by Easter Island's collapse narrative.
... LA-ICP-MS was chosen over other analytical methods (including XrF) as this technology 'is generally highly sensitive and can achieve high-precision results for trace elements, [and] has been widely used to trace the provenance of ancient stone artefacts for reconstructing patterns of interaction' (Ma et al. 2011: 890). Our methodology followed Carter and Dussubieux (2016) and Simpson and Dussubieux (2018). Analyses were conducted at TFM's EAF using a Thermo ICAP-Q ICP-MS connected to a New Wave UP213 laser for direct introduction of solid samples. ...
... USGS standard BHVO-2) but we did not have such a standard in our possession, and in the past, we successfully used glass standards to analyse Journal of Pacific Archaeology -Vol. 9 · No. 2 · 2018 silica-rich rocks such as carnelian (Carter & Dussubieux 2016). SrM 610, a soda-lime-silica glass doped with trace elements in the range of 500 ppm was used as an external standard. ...
Pacific and Rapa Nui (Easter Island) volcanologists and geologists have set the stage for the island’s archaeologists working in lithic sourcing studies by providing practical data regarding the island geodynamic activity, geomorphological formation and dating, and the macroscopic, microscopic, and elemental proprieties of Easter Island stone. Drawing upon this information, and the research collaboration between two active archaeological projects on Rapa Nui – the Easter Island Statue Project and the Rapa Nui Geochemical Project – this article presents: 1) a synthesis of a 5–meter field excavation of moai RR–001–156 in Rano Raraku, the moai statue quarry; 2) a 14C assessment which dates human presence around moai RR–001–156; 3) 31 basalt quarry and source site descriptions; and 4) laser ablation–inductively coupled plasma–mass spectrometry and principal component analyses of 21 archaeological and 117 geological samples. Our results trace the prehistoric transfer of basaltic resources from the Ava o’Kiri and Pu Tokitoki complex to the moai quarry at Rano Raraku during the AD 1400’s. This conclusion helps us to better understand sociopolitical and economic interaction during Rapa Nui prehistory.
... Detailed analysis of bead production technology and use wear can also help to narrow down the possible time period of their production and possibly indicate which of the various trade networks might have been responsible for their transport to East Africa. The chemical analysis of the carnelian beads using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) (Carter and Dussubieux 2016) indicates that they were all made from carnelian that is similar to what is documented from various geological sources in western and central India. Overall the beads from these three sites confirm the assumption made by earlier scholars, that carnelian beads in East Africa were traded from South Asia (ancient India) and were probably made by specialized craftspeople in South Asia itself, presumably western or central India. ...
... The raw material samples of the agate source database as well as the carnelian beads from the three sites presented here were geochemically characterized using LA-ICP-MS. This technique has previously been employed to determine the geologic provenience of agate/carnelian artifacts from Southeast Asia (Carter and Dussubieux 2016) and Mongolia (Kenoyer et al. 2022). LA-ICP-MS provides measurements for a wide range of major, minor and trace elements of solid materials. ...
Carnelian beads from three archaeological sites in East Africa, Manda, Kenya and Unguja Ukuu and Kwa Mgogo, Tanzania, have been studied using stylistic, technological and geochemical analyses. Broadly dated to between the seventh and fifteenth centuries CE, the bead shapes and manufacturing technology can be correlated to beads produced at workshops in ancient South Asia from around the same time period. Geochemical analysis using Laser Ablation-Inductively Coupled Plasma Mass Spectrometry indicates that the carnelian for producing the beads came primarily from the regions of Gujarat and Maharashtra in modern India. The diverse carnelian sources and different patterns of beads at the three sites illustrate the complex economic and social networks that linked communities in East Africa and South Asia.
... Researchers have employed LA-ICP-MS in a number of studies to identify and trace the geographic origins of gemstones by analyzing their constituent elements. Specifically, LA-ICP-MS has been successfully implemented in the multi-element analyses of minerals, including ruby, sapphire, diamond, topaz, precious corals, and emerald, aiming for mineral origin identification and differentiation [29][30][31][32][33][34][35]. Combined with linear discriminant analysis, LA-ICP-MS has an effective ability for source division on nephrite and demantoid garnets [30,31]. ...
... When using a nonlinear machine learning algorithm, the geographical source of emerald was distinguished blindly [32]. Besides, canonical discriminant analysis has achieved results for identifying agate and chalcedony in Cambodia and Thailand [33]. In this study, multi-element compositions in turquoise samples from five different regions were analyzed by LA-ICP-MS. ...
Microsampling elemental analysis is widely used for gemstone and mineralogy traceability. Using laser ablation inductively coupled plasma mass spectrometry combined with chemometrics, the contents of 56 elements in turquoise samples from 5 distinct producing areas in 3 nations were measured. An origin identification model for turquoise samples from various producing areas was established through random forest importance analysis, principal component analysis, and linear discriminant analysis. When combined with random forest importance screening, the traceability efficiency of principal component analysis is significantly improved. Moreover, by taking 48 elements as characteristic variables and introducing them into the discriminant model, a Fisher discriminant model for identifying the origin of turquoise was successfully established. The effective element fingerprint information of turquoise species is closely related to the species origin, and the accuracy of cross-validation reaches 99.5%, demonstrating the feasibility of the proposed model for the identification of the origin of turquoise samples.
... Another step in regional ornament research was recently made by Carter and Dussubieux (2016), who pushed LA-ICP-MS-based provenance analyses to complement the work done on manufacturing techniques. They showed that many stone beads found in Cambodia and Thailand had similar elemental compositions to raw materials from the Deccan Traps, and in so doing added fresh data supporting a complex view of late prehistoric exchange network. ...
... They showed that many stone beads found in Cambodia and Thailand had similar elemental compositions to raw materials from the Deccan Traps, and in so doing added fresh data supporting a complex view of late prehistoric exchange network. Overall, Iron Age stone ornament studies in Southeast Asia have, despite being fairly recent, significantly contributed to understanding complex late prehistoric social, economic and political developments and the region's cultural trajectory (Bellina, 2017;Bellina, 2014;Bellina, 2007;Bellina, 2003;Bellina, 2001;Carter, 2016;Carter, 2015;Carter, 2013;Carter and Dussubieux, 2016;Theunissen et al., 2000;Theunissen, 2003). ...
For many decades, the appearance of semi-precious stone ornaments in Mainland Southeast Asian late prehistoric assemblages was closely associated with external actors: Taiwan and Island Southeast Asia in the case of nephrite, and South Asia in the case of carnelian. Carnelian beads in particular have long been held as a type marker of early contact across the Bay of Bengal, from the mid-late 1 st millennium BC. With this paper we demonstrate, from the central-northern Myanmar settlement and cemetery sites of Oakaie and Nyaung'gan, not only the presence of semi-precious stone beads, but also their production during the Late Neolithic to Early-Mid Bronze Age, late 2 nd millennium to early-mid 1 st millennium BC. We employed the chaîne opératoire technique to establish reliable links between the industrial and funerary evidence, as represented by 489 finished beads and a vast quantity of production debris. The sites in question are chronologically-overlapping and separated by only five kilometres, but such ornaments are found across the region and it is of fundamental importance to provide a solid foundation to expand semi-precious stone ornament studies and unravel the complex networks of social interactions that led to their exchange.
... LA-ICP-MS was chosen over other analytical methods (including XrF) as this technology 'is generally highly sensitive and can achieve high-precision results for trace elements, [and] has been widely used to trace the provenance of ancient stone artefacts for reconstructing patterns of interaction' (Ma et al. 2011: 890). Our methodology followed Carter and Dussubieux (2016) and Simpson and Dussubieux (2018). Analyses were conducted at TFM's EAF using a Thermo ICAP-Q ICP-MS connected to a New Wave UP213 laser for direct introduction of solid samples. ...
... USGS standard BHVO-2) but we did not have such a standard in our possession, and in the past, we successfully used glass standards to analyse Journal of Pacific Archaeology -Vol. 9 · No. 2 · 2018 silica-rich rocks such as carnelian (Carter & Dussubieux 2016). SrM 610, a soda-lime-silica glass doped with trace elements in the range of 500 ppm was used as an external standard. ...
Pacific and Rapa Nui (Easter Island) volcanologists, geologists, and geochemists have set the stage for archaeological lithic sourcing studies by providing practical data regarding the island's geodynamic activity, geomorphological formation and dating, and the macroscopic, microscopic, and elemental proprieties of Easter Island stone. Drawing upon this information, and the research collaboration between two active archaeological projects on Rapa Nui-the Easter Island Statue Project and the Rapa Nui Geochemical Project-we trace the prehistoric transfer of basalt resources from the Ava o'Kiri and Pu Tokitoki quarry complexes to the moai (statue) quarry at Rano Raraku between AD 1455-1645. Our conclusions better highlight socio-political and economic interaction during Rapa Nui prehistory, while delineating the relationship between adze and pick production and moai manufacture. In this article, we report: 1) a synthesis of a five-meter deep field excavation of moai rr-001-156 in Rano Raraku; 2) a 14C assessment which dates human presence around moai rr-001-156; 3) 31 basalt quarry and source site descriptions; and 4) archaeometric data using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and principal component analyses of 21 archaeological and 117 geological samples.
... Nuestra metodolog?a adhiri? a la de Dussubieux et al. (2016) y Carter y Dussubieux (2016). Los an?lisis se realizaron en el Laboratorio de An?lisis Elemental (EAF) del Museo Field de Historia Natural (TFM) usando un ICP-MS Thermo ICAP-Q conectado con un Sistema de ablaci?n l?ser UP213 New Wave para la introducci?n directa de las muestras s?lidas. ...
... Nuestra metodolog?a adhiri? a la de Dussubieux et al. (2016) y Carter y Dussubieux (2016). Los an?lisis se realizaron en el Laboratorio de An?lisis Elemental (EAF) del Museo Field de Historia Natural (TFM) usando un ICP-MS Thermo ICAP-Q conectado con un Sistema de ablaci?n l?ser UP213 New Wave para la introducci?n directa de las muestras s?lidas. ...
Son muchas las publicaciones que han documentado los famosos ahu (plataformas), moai (estatuas), pukao (tocados) y una cultura casi milenaria. Aun así, se ha dedicado poca investigación a los recursos y artefactos de basalto y su geoquímica. Como parte del Proyecto Geoquímico Rapa Nui (2014 – 2017) hemos realizado un trabajo de campo exhaustivo y análisis arqueométricos y de la cultura material centrados en las industrias basálticas arqueológicas de la Isla de Pascua. Nuestros resultados destacan la forma en que los Rapanui prehistóricos fueron talladores polinésicos sofisticados en piedra que desarrollaron múltiples secuencias de reducción de herramientas para distintos tipos de material basáltico, creando en ese proceso paisajes antropogénicos sin par. Utilizando espectrometría de masas con plasma de acoplamiento inductivo con sistema de ablación por láser (LA– ICP– MS) de material de fuentes geológicas procedentes de 31 canteras y 61 artefactos del Museo Antropológico Padre Sebastián Englert, sostenemos que, así como con otras piedras culturalmente valiosas (obsidiana, escoria y toba), existió un acceso y utilización comunitarios de los recursos de basalto de Rapa Nui. A la vez, el acceso comunitario prehistórico a la piedra sugiere patrones de interacción sociopolítica y económica que incluyen la conectividad cultural en este asentamiento de la Polinesia oriental. Es por ello que nuestra conclusión arqueológica derivada de métodos empíricos arroja dudas sobre las interpretaciones sociopolíticas y económicas propuestas por el relato del colapso de Rapa Nui.
... Scholars have suggested several possible sources for the carnelian beads found in the 4 th millennium BCE southern Levant, though most assert that these beads originated in Upper Egypt (e.g., Hestrin and Tadmor 1963: 285;Bar-Yosef et al. 1977: 74-75;Braun and van den Brink 2008: 671;Ludvik 2018: 124;Milevski 2011: 173). As significant advances have been made in recent years with regards to geochemically tracing carnelian beads (Carter and Dussubieux 2016;Kenoyer et al. 2022: 8), it is hoped that beads from Fifa and other Early Bronze Age sites may be analyzed using this method in the future. Even without the advantage of such analysis, we may still utilize several aspects of morphological and manufacturing evidence from Fifa's assemblage to inferentially suggest where the beads were produced. ...
the Expedition to the Dead Sea Plain excavated a group of 15 tombs at the Early Bronze Age IA (c.3700-3400) cist-tomb cemetery at Fifa, Jordan. These tombs contained a variety of grave goods including beads made from carnelian. The present study employs morphometric data and microscopic indicators of manufacture and use to explore the relationship between carnelian beads, burial practices, manufacturing processes, and exchange. Manufacturing traces suggest that the beads from Fifa were created through a process of knapping and progressive stages of abrasion. Beads were perforated through pecking on one or two sides. Polish from use was observed on beads throughout the assemblage, suggesting that the beads were worn prior to their deposition, albeit for an unknown period of time. The amount of this use polish was highly variable suggesting that different beads were in use for greater or lesser periods of time. Morphometric and manufacturing data were utilized in tandem in order to suggest where the beads were produced. While a great deal of prior scholarship has suggested that carnelian beads found in the Early Bronze Age Levant originated in Egypt, we argue that some or all of these beads may alternatively have been produced in Northwestern Arabia or Eastern Jordan. This study demonstrates the value of systematic approaches to the study of beads in order to better understand processes of ritual behavior, craft production, and exchange.
... As D. Watters (1997) wrote: "Archaeologists tend to favour lowland South American sources because of undoubted linguistic and artifactual evidence linking the Caribbean's early Ceramic Age colonizers with that region, but empirical evidence of such sources is largely lacking". Ongoing work on turquoise and diorite will hopefully bear fruit in the coming years (Queffelec et al., 2022;Queffelec, 2021), while carnelian could also be a possibility, based on recent work in other parts of the world (Carter and Dussubieux, 2016;Theunissen, Grave and Bailey 2000;Insoll et al., 2004). ...
Personal ornaments, and especially those made of lithic materials, are an important part of the archaeological record, as they provide valuable insights into various aspects of past human societies. In the Caribbean islands’ Ceramic Age, lapidary artifacts exhibit remarkable abundance and diversity in terms of both raw materials and typology. Robust analysis of extensive datasets enables to address the questions of spatial and temporal distribution and diversity of lithic beads and pendants during this period. I demonstrate that the Early and Middle Ceramic periods exhibit higher raw material and typological diversity compared to later periods. Mineralogical and typological similarities are shown to be greater between sites attributed to the same period than between geographically close sites. The lapidary production during the Saladoid differs significantly between the continent and the archipelago. Some indications pointing to the Isthmo-Colombian area are proposed, which will require further research to enhance our understanding to the same level as that of the Caribbean islands, enabling advanced comparisons.
... Scholars have suggested several possible sources for the carnelian beads found in the 4 th millennium BCE southern Levant, though most assert that these beads originated in Upper Egypt (e.g., Hestrin and Tadmor 1963: 285;Bar-Yosef et al. 1977: 74-75;Braun and van den Brink 2008: 671;Ludvik 2018: 124;Milevski 2011: 173). As significant advances have been made in recent years with regards to geochemically tracing carnelian beads (Carter and Dussubieux 2016;Kenoyer et al. 2022: 8), it is hoped that beads from Fifa and other Early Bronze Age sites may be analyzed using this method in the future. Even without the advantage of such analysis, we may still utilize several aspects of morphological and manufacturing evidence from Fifa's assemblage to inferentially suggest where the beads were produced. ...
... Because carnelian is a semiprecious gemstone that was prized by early civilizations, the focus of many studies has been mainly from an archaeological perspective, e.g., [1][2][3]. Some regional geological reports mention carnelians briefly [4,5]; however, studies that focus strictly on the mineralogical and geological characterization of carnelians [6,7] are scarce, especially compared to the numerous studies of other types of microcrystalline silica such as agate, opal, and chert. ...
Carnelian occurs locally in New Jersey in the Newark basin as medium- to coarse-size pebbles in fluvial gravel and alluvium and colluvium formed from erosion of Lower Jurassic Preakness Basalt. Vesicles and molds of glauberite are preserved on lower surfaces and botryoidal textures on the upper surfaces of some pieces. The microstructure consists of length-fast chalcedony characterized by parallel fibrous bundles overlain by repetitive, wavy extinction bands. Only peaks of ɑ-quartz and minor moganite are recognized in X-ray diffraction patterns. Carnelian contains 97–98 wt.% SiO2, ~1.0 wt.% Fe2O3, and 1.0–1.4 wt.% LOI; other major elements are <0.1 wt.%. Trace element abundances are low except for Y, Nb, Ta, W, Th, and U. Rare earth element (REE) patterns display heavy REE enrichment and large negative Eu anomalies. Most trace elements were mobilized from Proterozoic sources, whereas Si was likely derived from the alteration of basaltic glass in the Preakness. Carnelian δ18OVSMOW values are high and range from +18.3 to +31.2‰, comparable to global occurrences of volcanic rock-derived chalcedony. We propose that carnelian precipitated in the first Preakness flow from the mixing of hydrothermal fluid with meteoric water under conditions of low temperature (20–80 °C) and neutral to slightly alkaline pH.
... In analyses of stone beads at the EAF, the same glass standards are generally used, but ten ablations, rather than four are needed to address the issue of heterogeneity in stone (19). Because the beads from the Bolivian context were potentially glass, we used only four points of ablation rather than ten. ...
... 10 In analyses of stone beads at the EAF, the same glass standards are generally used, but ten ablations, rather than four are needed to address the issue of heterogeneity in stone. 11 Because the beads from the Bolivian context were potentially glass, we used only four points of ablation rather than ten. As a result, the quantifications for major and trace element concentrations may be less representative of the stone as a whole, and therefore less accurate than those for glass artifacts or stone artifacts analyzed with ten ablation points. ...
... High-quality carnelian and other semiprecious stone was imported in raw form from South Asia (Carter and Dussubieux 2016), and worked initially by highly skilled foreign specialists to produce ornaments which conformed to the accepted regional style ( Figure 20.6) including complex geometric double pyramid, lozenge, and icosahedral shapes, while those in glass include bracelets and beads Bellina 2017, 2018). Faceted lapidary glass beads also found at Ban Don Ta Phet, were made using techniques similar to those used for quartz beads (Figure 20.7). ...
Southeast Asia is one of the most significant regions in the world for tracing human prehistory over a period of 2 million years. Migrations from the African homeland saw settlement by Homo erectus and Homo floresiensis. Anatomically Modern Humans reached Southeast Asia at least 60,000 years ago to establish a hunter-gatherer tradition, adapting as climatic change saw sea levels fluctuate by over 100 meters. From about 2000 BC, settlement was affected by successive innovations that took place to the north and west. The first rice and millet farmers came by riverine and coastal routes to integrate with indigenous hunters. A millennium later, knowledge of bronze casting penetrated along similar pathways. Copper mines were identified, and metals were exchanged over hundreds of kilometers as elites commanded access to this new material. This Bronze Age ended with the rise of a maritime exchange network that circulated new ideas, religions and artifacts with adjacent areas of present-day India and China. Port cities were founded as knowledge of iron forging rapidly spread, as did exotic ornaments fashioned from glass, carnelian, gold, and silver. In the Mekong Delta, these developments led to an early transition into the state known as Funan. However, the transition to early states in inland regions arose as a sharp decline in monsoon rains stimulated an agricultural revolution involving permanent plowed rice fields. These twin developments illuminate how the great early kingdoms of Angkor, Champa, and Central Thailand came to be, a vital stage in understanding the roots of modern states.
... One aspect of documentation that was not conducted is the geo-chemical sourcing of the carnelian or agate itself. The sourcing of carnelian has been carried out using Instrumental Neutron Activation Analysis (INAA) and Laser Ablation Inductively Couples Mass Spectrometry (LA-ICP-MS) in South and Southeast Asia (Carter and Dussubieux, 2016;Law, et al. 2013) as well as in Arabia (Cattani, et al. 2019) and East Asia (Kenoyer, et al. 2022). ...
An assemblage of 72 carnelian and agate beads recovered from secondary debris removal associated with the Temple Mount Project, Jerusalem, provides new insight into the long chronology of human activity in an area that saw multiple periods of building, destruction, and rebuilding. Chronological attribution has been done by taking into consideration the overall shape and morphology of the beads, as well as aspects of production technology, specifically perforations made with distinctive types of drills. Based on stylistic, morphometric, and technological features, the earliest beads date to around the third millennium BCE, if not earlier, while others probably date between the Middle Bronze Age and the Iron Age. Most of the beads were made in styles and using technologies that date between the early centuries BCE/CE through the Medieval/Islamic period. A few beads appear to be very modern and attest to their continued importance to individuals active in the Temple Mount area. Carnelian beads are commonly associated with personal adornment in the form of necklaces, earrings, pendants, clothing decoration, or praying necklaces, and provide evidence for the deposition or loss of small articles atop this central location for over three millennia of human occupation in the vicinity of Jerusalem.
... Two carnelians from Cos°ava (Banat, Romania) were investigated using LA-ICP-MS by Schmidt et al. (2012a). Geological sources for agate and carnelian from Thailand, Iran and India have been investigated by Carter and Dussubieux (2016). ...
The chapters contributed to the volume recognize the important and diverse contributions of mineralogy to the valorization, characterization, interpretation and conservation of cultural heritage. The book focuses on examples of materials and methodological issues rather than technical/analytical details. We have attempted to deal with the cultural heritage materials in chronological order of their technological developments, to relate them to past human activities, and to highlight unresolved problems in need of investigation.
... Bellina 2002Bellina , 2003Ramli et al. 2009;Carter 2015;Bellina 2016). Carter and Dussubieux (2016) used the geochemical signature to prove the sources of the Iron Age carnelian beads from SE Asia, and they concluded that most samples were made from raw materials from the Deccan Traps, northwest India. Our samples are found to have been treated into black or dark brownish black to imitate onyx or black onyx. ...
Iron Age treated carnelian beads and their natural counterparts from SE Asia have been discussed in terms of attribution of transition and lighter elements in their matrix. They were investigated by using synchrotron techniques (XRF: X-ray fluorescence, XANES: X-ray absorption near edge structure, and XPS: X-ray photoelectron spectroscopy) and SEM-EDS: scanning electron microscope-energy dispersive spectroscopy. Ferrihydrite or ferrihydrite + goethite have been found as the causes of color. The treated stones were subjected to the sugar + sulfuric acid treatment of about 1800-year BP. This work has fulfilled information about the treatment in the ancient chalcedony to the archeomineralogy archive.
... Data came from fine compositional and technological analysis of crafts products circulating on these networks. Those include, to cite only a few, the Indian-type of knobbed or decorated high-tin bronze bowls (Glover 1991;Srinivasan and Glover 1995;Srinivasan 1997Srinivasan , 2010Pryce et al. 2011Pryce et al. , 2014, glass (Dussubieux 2001;Dussubieux, Gratuze, and Blet-Lemarquand 2010;Dussubieux et al. 2012;Carter 2013), chalcedony ornaments (Theunissen 1998;Theunissen, Grave, and Bailey 2000;Bellina 2001Bellina , 2003Bellina , 2007Theunissen 2007;Carter 2013;Carter and Dussubieux 2016), nephrite ornaments (Hung et al. 2007;Hung and Bellwood 2010), Indian fine wares such as rouletted ware and kendi-type of ware (Bouvet 2006(Bouvet , 2011(Bouvet , 2012, Sa Huynh-Kalanayrelated ware (Favereau 2015;Favereau and Bellina in press) and metals (Pryce, Bellina-Pryce, and Bennett 2008;Murillo-Barroso et al. 2010;Pryce et al. 2011Pryce et al. , 2014. Beside helping to trace networks and their evolution through time, these databases began to provide firmer grounds to reconstruct socioeconomic contexts and cultural interactions. ...
... As in the case of hard stones (Bellina, 2007(Bellina, , 2014 and possibly of copperbased industries , the sudden appearance of complex skills necessary for the production of glass ornaments at Khao Sam Kaeo suggests a transfer of artisans, likely from India. Again, as for siliceous stones which were most likely imported from India (Carter and Dussubieux, 2016), raw glass found at Khao Sam Khao was imported from India through the Bay of Bengal Interaction Sphere to be locally transformed into ornaments with a style shared by communities of the South China Sea Interaction Sphere within which they were then "distributed" as far as the Philippines (Dussubieux and Bellina, 2017). ...
Khao Sek, a coastal settlement located in the Upper-Thai Peninsula and 80. km south of the early urbanized port of Khao Sam Kaeo in the Chumphon province, yielded an impressive quantity of glass waste and ornaments suggesting that glass bracelets and beads were manufactured at the site as early as the 4th c. BCE. This article discusses the glass material found at Khao Sek using typological observation but also elemental analysis with laser ablation - inductively coupled plasma - mass spectrometry. Beyond obvious morphological resemblance, compositional analyses of the glass confirm similarities between the glass industries at Khao Sam Kaeo and Khao Sek and the existence of a fairly standardized glass ornament production at an early period. This article provides new arguments to discuss the fashioning of a regional standardized craft system as early as the mid-first millennium BC and its role in participating in the production of a pan-regional style, the "Late Prehistoric South China Sea style". Finally, this study contributes to define the political developments that took place in the Upper-Thai Peninsula for the period 500 BCE-500 CE, hypothesizing the emergence of a ranked and complementary confederation of ports-of-trade.
... Except for Sa Huynh-Kalanay ceramics, those goods were interpreted as mere imports until a decade ago when technological analysis began to suggest that some of the emblematic ones, the hard stone ornaments, were made locally with foreign techniques and adapted to local taste (Bellina, 2001(Bellina, , 2007. Since then, research has generated increasing evidence that these widespread objects were most often locally made, combining imported motifs and shapes (Flavel, 1997), exotic materials (Carter, 2015;Carter and Dussubieux, 2016;Hung and Bellwood, 2010;Hung, in press) and skilled exogenous techniques that originated in South Asia and East Asia (Bellina, 2001(Bellina, , 2003(Bellina, , 2007Bellina et al., 2012;Bouvet, 2011;Dussubieux and Bellina, in press;Favereau, 2015;Favereau and Bellina, 2016;Pryce et al., in press). The hybrid nature of these products reveals that social and political interactions within and between societies of the two sea basins during late prehistoric periods were much more complex and dynamic than expected. ...
... There are exciting fieldwork methodologies, such as Li-DAR (Hanus and Evans 2015) and ground penetrating radar (Duke et al. 2016) that are beginning to enable richer and more rapid assessment of our sites, which should improve the efficiency and quality of field data acquisition. Expanded development and application is needed of postexcavation methodologies, including applications of archaeometric techniques (e.g., Carter and Dussubieux 2016;King et al. 2015: Pryce et al. 2014). There is a backlog of legacy work that needs to be published, and Ban Chiang is only one of many insufficiently published excavations 1 An earlier version of this text was prepared for a keynote address at the European Association of Southeast Asian Archaeologists (EurASEAA), 14 th International Conference that took place in Dublin, September 18-21 2012. ...
p>Abstract: An argument is presented for Southeast Asian archaeologists to replace the Birds Eye View/Rear View Mirror paradigm prevalent during the mid-twentieth century with a forward-facing, “emergent” paradigm in alignment with current trends in archaeological theory. An earlier version of this text was prepared for a keynote address at the European Association of Southeast Asian Archaeologists (EurASEAA), 14th International Conference that took place at in Dublin, September 18-21 2012.</p
... As for style, only minor differences can be observed: the raw materials are the same and used in comparable proportions, even if the quality of the carnelian is slightly better at Khao Sam Kaeo; the morphologies are mostly shared; the morphometry is also comparable despite a few larger pieces at Khao Sek; and at Khao Sek, the overall quality is good but not quite the exceptional level seen at Khao Sam Kaeo. Recent compositional evidence supports the assumption that cornelian used during Metal Age Southeast Asia was initially imported from the Deccan Plateau of Central and southern India (Carter and Dussubieux, 2016). ...
This paper is a technological reconstruction of Khao Sek stone ornaments industries and its comparison with that of the port-city of Khao Sam Khao. Both production centres are characterised by an identical production modelimplementing the same Indian complex technologies to generate a similar pan-regional style. This study leads me to conclude that as early as the 4th c. BCE in the Kra Isthmus, a standardised regional production system existed involving foreign complex technologies of Indian and (considering the nephrite) East Asian origins. Based on excavations and other industries data, this study allows inferring the political context: that of a single political entity constituted of a confederation of complementary or heterachically/hierarchically-organised ports-of-trade controlling different transpeninsular routes/river systems.
... Data came from fine compositional and technological analysis of crafts products circulating on these networks. Those include, to cite only a few, the Indian-type of knobbed or decorated high-tin bronze bowls (Glover 1991;Srinivasan and Glover 1995;Srinivasan 1997Srinivasan , 2010Pryce et al. 2011Pryce et al. , 2014, glass (Dussubieux 2001;Dussubieux, Gratuze, and Blet-Lemarquand 2010;Dussubieux et al. 2012;Carter 2013), chalcedony ornaments (Theunissen 1998;Theunissen, Grave, and Bailey 2000;Bellina 2001Bellina , 2003Bellina , 2007Theunissen 2007;Carter 2013;Carter and Dussubieux 2016), nephrite ornaments (Hung et al. 2007;Hung and Bellwood 2010), Indian fine wares such as rouletted ware and kendi-type of ware (Bouvet 2006(Bouvet , 2011(Bouvet , 2012, Sa Huynh-Kalanayrelated ware (Favereau 2015;Favereau and Bellina in press) and metals (Pryce, Bellina-Pryce, and Bennett 2008;Murillo-Barroso et al. 2010;Pryce et al. 2011Pryce et al. , 2014. Beside helping to trace networks and their evolution through time, these databases began to provide firmer grounds to reconstruct socioeconomic contexts and cultural interactions. ...
... Another common undercurrent in many of these papers concerns one of the most exciting recent developments in bead research: the expansion of non-destructive compositional analysis techniques to examine the elemental compositions of beads. Of these techniques, laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) seems to have become the most widespread, especially in the analysis of glass (Gratuze, 2013), but has also been used successfully to examine stone beads (e.g., Carter and Dussubieux, 2016;Carter, in press;Insoll et al., 2004). Such analytical techniques allow for the identification of unique characteristics of a bead that may not be visible to the naked eye. ...
In this introduction we offer a brief background on Peter Francis, Jr., Asia's Maritime Bead Trade, and our motivation for putting together this special issue. We summarize the papers in the issue and conclude by proposing future directions for continued research on beads in Asia.
You can download this article for free until February 5, 2025 using this link:
https://authors.elsevier.com/c/1kHH~,rVDBjaIU
Abstract
We conducted Sr and Nd isotope analysis on 27 glass beads found at Angkor Borei, southern Cambodia (200 BCE-200 CE) belonging to three different glass types: m-Na-Al 1, m-Na-Ca-Al and v-Na-Ca. The m-Na-Al 1 and m-Na-Ca-Al glass types split quite similarly into two sub-groups based on their εNd signatures. High εNd values are associated with a possible Sri Lankan provenance whereas low εNd values point toward a possible eastern South Indian provenance. For both glasses, those sub-groups are correlated to specific trace element signatures and more specifically to distinct Cr and V levels. The high εNd m-Na-Al 1 and m-Na-Ca-Al glasses have low Cr and V concentrations and the low εNd m-Na-Al 1 and m-Na-Ca-Al glasses have higher Cr and V concentrations. Extrapolating these observations to all the Angkor Borei m-Na-Al 1 and m-Na-Ca-Al glass samples analyzed for elemental compositions, we were able to attribute a provenance to most of them. Most of the samples from Angkor Borei seem to come from eastern South India. The v-Na-Ca glass samples were manufactured in the Middle East but from possibly at least two different locations. For this study, we noted that the addition of manganese in glass for coloring purpose could also bring strontium and other elements that interfere with the strontium signature of the glass and also its trace element signature (including V and Cr).
In India, the organization of the ancient glass industries that produced, starting around the mid-1st millennium BCE, huge quantities of small drawn beads that were traded both locally and all over the Indian Ocean and beyond, is poorly known. Elemental compositions conducted on glass beads found in India and on Indian beads found elsewhere show a great variability that could be linked in some cases to different production regions (Northern, Southern, and Western India). However, a more precise provenance attribution and the identification of regionally distinct production centers was not possible without additional research. Ethno-historical references show that glass was often produced from one single ingredient, called reh. We collected raw material samples from selected regions within the subcontinent. This paper reports on both the elemental compositions of these raw material samples obtained using laser ablation—inductively coupled plasma—mass spectrometry and their isotopic compositions including Pb, Sr, and Nd. The results were compared to elemental and isotopic data available for known Indian glass artifacts recovered from sites within and outside India. Our results show that some regions within India are more likely than others to have been the loci of glass production in ancient times.
This handbook is currently in development, with individual articles publishing online in advance of print publication. At this time, we cannot add information about unpublished articles in this handbook, however the table of contents will continue to grow as additional articles pass through the review process and are added to the site. Please note that the online publication date for this handbook is the date that the first article in the title was published online. For more information, please read the site FAQs.
Of the more than 2,150 beads and pendants examined in this
article, the overwhelming majority come from a ceramic vessel
found on the northern side of the lower church at Banganarti,
in a layer dated to the eighth to tenth centuries. The remaining
objects were collected from other Banganarti contexts dated between
the sixth/seventh and fourteenth centuries. The beads and
pendants were made of organic and inorganic materials (resin,
ostrich eggshell, stone, faience, glass) using diverse techniques.
Combined macroscopic and chemical compositional analyses
show raw sources in India and possibly Yemen for carnelian
and rock crystal beads. While the glass of some specimens was
sourced in Egypt and the Levant, most beads were made of glass
produced in the Middle East.
In the present article, we report the comparative results obtained from the analysis of semi-precious stones of different classes (idiochromatic, allochromatic and pseudochromatic) using laser-induced breakdown spectroscopy (LIBS) coupled with multivariate analysis. The point detection capability of LIBS is successfully applied for the identification of spatially distributed elements at various spots/colouration/bands in the gemstone and the identification of mineral inclusion in stones samples. Since chromophores or mineral inclusions are responsible for the colouration of the stones, the sensitivity of the point detection capability allows identification of the elements responsible for the colouration of the stones. This study reveals that white bands on the lapis lazuli samples correspond to the mineral calcite also a possibility of the presence of pyrite in the stone. Based on the spectral lines of the trace/minor elements, stones are classified in different groups by applying principal component analysis on LIBS spectral data of the stones. Visually distinct coloured zones are clustered in the same group due to their similar matrix. Further partial least square regression (PLSR) analysis of LIBS spectral data has been used to investigate Si concentration in stones. Therefore, we firmly believe that the results from the present work extend the application of LIBS together with multivariate analysis for the identification of the mineral responsible for different colours in semi-precious stones.
In recent years our understanding of ancient maritime networks has evolved significantly. Extensive international joint excavations and a heightened interest in collecting ancient objects among local people have altogether yielded a significant number of Roman artefacts both from Mainland and Island Southeast Asia. Regarding the types of these Roman objects, a quantity of engraved gems bearing western characteristics emerges from the collected materials thereby suggesting recognition and possibly even some degree of appreciation by the local cultures. This paper examines the categories and distribution of Roman engraved gems discovered in Southeast Asia, and aims to show possible imprints on forming evaluation/acceptance of these non-local goods by the receiving cultures.
Angkor Borei, Cambodia was an important urban center related to the early first millennium C.E. polity known as Funan. Excavations in the protohistoric period Vat Komnou Cemetery site uncovered over 1300 glass and stone beads, which are important material indicators of trade. In this article, we review data from earlier studies and add new previously unpublished data on glass and stone beads from this collection as well as previously unpublished glass compositional analyses from the nearby site of Oc Eo, Vietnam. Examinations of the glass beads highlight the presence of large quantities of high alumina mineral soda glass associated with Sri Lankan or South Indian bead production as well as smaller quantities of other glass types in circulation throughout Southeast Asia. Compositional and morphological studies of agate/carnelian beads show strong affinities with the Indian bead industry, while the garnet beads came from raw material sources in southern India. Overall, Angkor Borei's bead collection shows strong contacts with different regions of South Asia. Comparison with the bead assemblages of other contemporaneous sites demonstrate strong affinities with sites farther inland, such as Phum Snay and Prei Khmeng, Cambodia and Ban Non Wat, Thailand rather than other maritime coastal sites in Southeast Asia. We argue that the stone and glass beads at Angkor Borei are related to intensified interaction with South Asia and that elites at Angkor Borei used these exotic prestige goods to build alliances with sites farther inland forming an intraregional exchange network we call the Mekong Interaction Sphere.
The chapters contributed to the volume recognize the important and diverse contributions of mineralogy to the valorization, characterization, interpretation and conservation of cultural heritage. The book focuses on examples of materials and methodological issues rather than technical/analytical details. We have attempted to deal with the cultural heritage materials in chronological order of their technological developments, to relate them to past human activities, and to highlight unresolved problems in need of investigation.
Dy, Ho, Er, Tm, and Sc mono-element solution certified reference materials (CRMs) with the certified value of 983.3 μg g−1 were developed with high-purity lanthanide oxides by using a novel purity characterization strategy. In the purity characterization process, complexometric titration was first employed to acquire the total metal ion concentration reacting with EDTA. Twenty-seven non-lanthanide impurities were measured by an external ICP-MS method with three multi-element calibration solution CRMs as calibrants. To avoid REO(H)+ interference from the main lanthanide matrix, two strategies namely LA-ICP-MS and MD-ICP-MS were optimized and used for the measurement of 15 rare earth impurities. The purity of lanthanide oxide material was obtained by subtracting the 42 impurities from the total metal ions reacting with EDTA. After purity characterization, the solution CRMs were prepared with a gravimetric method, and the CRM values were verified with corresponding NIST rare earth solution SRMs. It was shown that 15 units with duplicate analysis are enough to demonstrate the homogeneity of these candidate reference materials. The statistical results also showed no significant trends in stability tests for 24 months. The final uncertainties of the CRMs were evaluated by combining uncertainty contributions including the sample characterization and gravimetric preparation (uchar), between-bottle homogeneity (ubb), and stability (us). The relative expanded uncertainties of the five CRMs are 0.5%. These CRMs are primarily intended for use in the measurement and calibration procedures of lanthanide analysis in environmental and geological areas. Most importantly, the purity characterization strategy of this study will provide a new idea for the certification of high-purity and mono-element solution reference materials.
Stone and glass beads have been found at Iron Age (500 bc–ad 500) sites across Southeast Asia and are often assumed to be indicators of contact with South Asia. However, recent research on glass, agate, and carnelian beads indicates there may have also been local production of these materials. In Cambodia, two different types of garnet beads have been identified at several Iron Age sites. The first type is spherical, well-polished, and appears to have been drilled with a diamond drill, a drilling technique that is strongly associated with Indian bead production. The second type of garnet bead is unpolished, unshaped, and drilled using a variety of different drilling methods. Based on these initial differences, it was hypothesized that there were two different bead-making traditions represented amongst the garnet beads, and that the second type of garnet bead may have been locally produced. To investigate this question more thoroughly the garnet beads were analyzed using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) in order to determine their chemical composition. Geological source samples from a variety of garnet sources across South and Southeast Asia were also analyzed using LA-ICP-MS. Results indicate that LA-ICP-MS is an excellent tool for differentiating between garnet sources and analyzing archaeological garnet artifacts with minimal damage. Furthermore, the results of the study confirm that the two types of beads were made from distinctly different garnet sources, although the locations of these sources remain unknown.
Stone and glass beads are important artifacts in Southeast Asia as they are amongst the earliest objects from South Asia found in the region, and frequently seen as symbols of Indian influence and increasing socio-political complexity. Peter Francis Jr.'s writings regarding the production and exchange of beads in Southeast Asia have been influential to archaeologists who have viewed beads as prestige objects that were traded widely and produced at important urban centers in Southeast Asia. However, the field of beads studies in Southeast Asia has greatly expanded in the past 15 years and benefitted from new excavations and scientific techniques. In this article, I review Peter Francis' hypotheses regarding the production and exchange of beads in Southeast Asia from 500 BCE to the early second millennium CE. I then synthesize recent work by scholars that has transformed our understanding of the manufacture and trade of beads. I argue that this work has largely disproven Francis' model of bead production and interaction between South and Southeast Asia. Instead, there appear to have been multiple phases of bead production and exchange between the two regions, which reflect complex interaction networks between South and Southeast Asia and within Southeast Asia.
Control over the exchange of prestige goods is an important component of emerging socio-political complexity in many ancient societies. During the Iron Age period (500
bce–ce
500), communities in mainland Southeast Asia were undergoing rapid socio-political changes, due in part to new interactions with societies from South Asia. As objects made from exotic raw materials and using complex technologies, stone and glass beads are one type of prestige object from South Asia that were exchanged widely across Southeast Asia. This study examines beads from 12 sites in Cambodia and Thailand. Morphological and compositional analyses using LA-ICP-MS resulted in the identification of different bead types that were circulated in distinct exchange networks. Initially, beads were exchanged within a pre-existing South China Sea network. However, as trade with South Asia intensified in the late Iron Age, exchange networks in Southeast Asia expanded, with an increase in the quantities of beads circulated. These results show the utility of studying beads as a means of examining trade and emerging socio-political complexity. Lastly, in considering evidence for control over the exchange of beads, I propose looking to an emerging state in the Mekong Delta.
James W. Lankton, Laure Dussubieux and Bernard Gratuze
Glass from Khao Sam Kaeo: Transferred technology for an early Southeast Asian exchange network
In this paper we first summarize glass craftwork at Khao Sam Kaeo, and then focus more closely on the glass evidence for external contacts of the site, as well as on the possible origins for Khao Sam Kaeo glass technology. With an emphasis on both technological processes and chemical compositions, we compare the glass from Khao Sam Kaeo with over 600 samples from other sites in South and Southeast Asia, and conclude the following:
– The people of Khao Sam Kaeo actively participated in a Southeast Asian exchange network for high quality glass and stone ornaments that extended from Myanmar to the Philippines. This network appears to have been well established by the 4th to 3rd century BCE.
– While the technology for producing glass ornaments, and possibly raw glass, was most likely transferred from some other area, possibly northern India, the great majority of the products in this early exchange, certainly for glass and possibly for stone, were manufactured in Southeast Asia and not imported from India or Sri Lanka.
In addition, glasses with chemical compositions characteristic of the sites linked in this early network are rare at Angkor Borei, Noen U-Loke, Oc Eo and Khlong Thorn, suggesting profound changes in Southeast Asian exchange toward the end of the first millennium BCE.
Cultural contact, exchange and interaction feature high in the list of challenging topics of current research on European Prehistory. Not far off is the issue of the changing role of monuments in the making and maintaining of key cultural devices such as memory and identity. Addressing both these highly-debated issues from a science-based perspective, in this paper we look at an unusual case study set in southern Iberia and illustrate how these archaeological questions can benefit from robust materials-science approaches.
Beads made of glass and stone found at Iron Age period sites (500 BC – AD 500) in Southeast Asia are amongst the first signs for sustained trade and sociopolitical contact with South Asia. Because of this, they have become important artifacts for scholars wishing to better understand trade networks and sociopolitical development during this period. Using compositional analysis scholars can identify the recipes used to make these glass beads and in some cases this can be tied back to specific places or time periods. Current research indicates there were multiple glass bead production centers across South and Southeast Asia during this period. However there has not yet been a comprehensive examination of glass beads from Iron Age sites in Cambodia. This paper aims to fill this gap by presenting the results from a compositional analysis of glass beads from six Iron Age sites in Cambodia. Using a virtually non-destructive compositional technique (LA-ICP-MS), I was able to determine the presence of at least two glass bead-trading networks in Cambodia during the Iron Age.
In the present study two analytical methods are applied to characterize chert artefacts and raw materials from northeastern Bulgaria (Ludogorie region): petrographic observation and laser ablation inductively coupled plasma mass spectrometry). Archaeological samples from 12 Chalcolithic sites from Bulgaria are analyzed as well as raw material from 6 outcrops in northeastern Bulgaria are identified and documented during a survey in 2012 when many raw material samples were collected. The chert raw material mostly occurs in various Quaternary secondary deposits, originating from destruction and disintegration of the Lower Cretaceous (Aptian) limestones in the area. The paper is aimed at tracing the provenance of the artefacts based on their petrographic characteristics and geochemical composition. The archaeological evidence shows a wide distribution of the Ludogorie chert throughout the country.On the basis of micropetrographic observations, Gurova and Nachev (2008) described two main chert types (Ravno and Kriva Reka). Our petrographic study confirmed the previous results and an additional chert type was distinguished, originating from primary and secondary deposits (quarries in Koprivetz and Krasen villages) and is represented by silicified limestones (bioclastic-peloidal packstones or grainstones). It is noteworthy that the first two types of chert were largely used for prehistoric artefact manufacturing while the last one is not attested among studied assemblages at all.
The interlocking of maritime basin network that took place with development of the Maritime Silk Roads by the late first millennium BC led to major cultural transfers. This research investigates Southeast Asia’s cultural integration and takes in consideration what I call a South China Sea network culture, a result of long-established and extensive connectivity of its populations. The assumption is that this cultural matrix also laid the ground for socio-political practices hypothesized to be at the core of identity building and cultural transfers. These issues are investigated through the technological analysis of hybrid ornament industries in a recently excavated early city-port of the South China Sea which developed with the Maritime Silk Roads that thrived from the fourth to the first centuries BC. This enclosed cosmopolitan settlement hosting populations from various Asian horizons was structured by socio-professional quarters. This node concentrated various craft centres where artisans of different origins made culturally hybrid products with what were then the most advanced technologies. The chronological sequence allows characterization of the evolution of these industries along with the socio-political strategies which they may have served and how otherness was handled in the construction of social identity.
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was applied to detect trace elements in agate from Permian volcanics (Nowy Kościoł, Poland) in low concentrations and with high spatial resolution. The used LA-ICP-MS system consists of a DUV 193 laser ablation system linked to a Thermo Finnigan Element 2 mass spectrometer. The use of a 193 nm ArF excimer laser (50-200 mJ energy output) and the standards NIST 611 and NIST 612 enables to produce and analyse small crater diameters down to 5 μm. Trace-element profiles have been analyzed for the elements Ti, Ge, Al, Fe, Mn, U, Th, Ba, Sr, Rb, Cs, and Y in the ppm-and sub-ppm level. The concentrations of the REE are sometimes below the detection limit of the method. Almost all elements (except Cu) display higher contents in chalcedony than in the macrocrystalline quartz. Fe, for instance, shows a 100 times higher concentration in agate bands compared to quartz, which may be due to finely distributed iron oxide particles in the chalcedony which probably act as colour pigments. The trace elements in agate are released simultaneously with Si during alteration of the surrounding volcanic rocks. Oxygen isotope data indicate that silica accumulation and agate formation took place at temperatures below 120°C. The characteristic trace-element distribution patterns in agate result from a "self-purification" process during crystallization of chalcedony and quartz from a silica gel.
A key tenet of Clovis period hunter-gatherer mobility is the utilization of large ranges based on the appearance of exotic raw materials, particularly chert, in Clovis assemblages. The identification of the sources of chert in Clovis period assemblages is problematic as it has relied on macroscopic properties. Macroscopic characteristics of chert can be highly variable in a single outcrop, occur across very large areas, and have correlates in unrelated and far removed contexts. A instrumental geochemical approach was utilized that potentially offers advances in the capacity to link chert artifacts to their sources. Trace
element data was recovered from 33 Clovis period projectile points from the Gault Site (41BL323) using Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry (LA-ICP-MS). This data was compared to trace element data recovered from 224 primary geologic samples of chert from multiple primary sources across the Edwards Plateau in Texas. The Clovis points were compared to the geologic sources using canonical discriminant analysis to establish group membership at three spatial scales: macroregional (greater than 500 kilometers), regional (between 30 and 500 kilometers), and local (between 1 and 30 kilometers). It was found at the macro-regional scale that 21 of the 33 Clovis points were to be geochemically similar to Edwards Plateau sources. At the regional scale, 15 of the 21 identified Edwards Plateau Clovis points could be attributed to a particular source. Lastly, only two Clovis points could be identified to particular sources at the local scale.
Sourcing artifacts is a key method for addressing anthropological issues of mobility and interaction. Although chert was one the most common toolstones used in prehistory, sourcing chert artifacts remains problematic. In this study an approach for sourcing chert is introduced that links a specific sampling protocol, Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS), and multivariate statistical analysis. The effectiveness of this approach is demonstrated through a controlled experiment examining intersource and intrasource variability at four different scales of analysis. The statistical analysis at four spatial scales allows determination of the spatial resolution of the chemical matching procedure outlined here. In this experiment geologic chert samples from the Edwards Plateau of Texas of known provenience are chemically evaluated allowing comparison of their expected origin against their known origin. This experiment used Edwards Plateau chert as it is a high quality material and was a major lithic source across the Southern High Plains and was often transported great distances. Macroscopic identification of Edwards Plateau chert can be problematic and at its best is unable to effectively discern from where within the 120,000 km2 of the region cherts originated. An understanding of the geological formation processes of chert provides a useful framework for addressing this issue. This study shows that through an effective methodology Edwards Plateau chert can be sourced to a finer spatial scale than previous studies.
For geological studies, interest in mass spectrometry with an inductively coupled plasma as an ion source and its association with laser ablation as a sample introduction technique (LA-ICP-MS) has steadily increased during the past few years and is now being developed in other fields such as archaeology. After a description of the analytical procedure and the calculation method, we show the potential of this technique to characterize, almost non-destructively, archaeological artefacts. Among the 70 elements that could be routinely analysed by LA-ICP-MS with detection limits below the ppm level, we choose to determine the more critical ones in order to evaluate the geochemical models of the magmatic process (major elements, rare earths and some transition elements). A detailed survey of Cappadocian obsidian flows is given, and includes the characterization of nine different sources. Evidence of complex trade activities is clearly shown by the obsidian tools found at different prehistoric sites (from Neolithic to Bronze Age levels) in the Mediterranean and the Near East. New results obtained on some archaeological sites located in Turkey, Syria and Cyprus are presented. They show the importance of Cappadocian sources in obsidian trade. Our results show that LA-ICP-MS allows a non-destructive analysis of archaeological objects and that it combines the advantage of the different classical methods used to characterize obsidian sources (mainly XRF and INAA) with high sensitivity and rapidity. Thus LA-ICP-MS appears to be a very powerful analytical tool and, at this time, this technique is the only one which can non-destructively determine such an important number of elements with such low detection limits.
A trade in carnelian from Gujarat, especially the town of Khambhat, and parts of sub-Saharan Africa is often discussed in the literature. To date, such assertions have been based upon putative visual parallels between African and Indian samples, and upon historical sources. This paper outlines the results of UV-LA-ICP-MS analysis and subsequent principal component analysis undertaken in an attempt to differentiate Gujarati and West African carnelian samples, and thus begins to allow inferences to be made regarding a possible trade in carnelian between these two regions primarily in the medieval period, based upon more objective data.
Planar cross stratification, trough cross stratification, imbricate structure and channel structure observed in Jhagadia, Babaguru and Tarakeshwar Formations indicate fluvial depositional environment. Oscillation ripple marks preserved in the Kand Formation suggest transitional conditions. Graded bedding seen in Jhagadia, Tarakeshwar and Vagalkhod Formations indicate deposition by turbidity currents. Convolute laminations and ball and pillow structure by sediments belonging to Babaguru Formation indicate intrastratal deformation and slumping, perhaps on a delta. Colour banding observed in the sandstones of the Babaguru Formation suggests oxidising environment in a tranquil water body.
This chapter reviews turquoise sources and their analysis in Mesoamerica and the southwestern US context. As civilizations expand, the demand for rare resources becomes more systematized. Systematic demands are concomitant with systematic acquisition techniques. Mesoamerica, viewed as an ancient world system, certainly had such demands. Rare resource source areas eventually became so heavily exploited by Mesoamericans that province formation and/or colonization was finally reached in some cases. The term turquoise is used in two quite different manners: (1) the narrow definition, which is a chemical one, and (2) a broader designation, a cultural term embracing a whole range of blue and blue–green stones. The cultural term would not only include chemical turquoise but also certain types of malachite, azurites, chrysocollas, a green garnet, and several other copper-bearing minerals not yet fully identified. The turquoises appear to have been the second Teotihuacan luxury rare resource enterprise. Evidence suggests that Teotihuacan was trading for turquoises before attempts to control the rare resource province more directly were made.
Control over the exchange of prestige goods is an important component of emerging socio-political complexity in many ancient societies. During the Iron Age period (500
bce–ce
500), communities in mainland Southeast Asia were undergoing rapid socio-political changes, due in part to new interactions with societies from South Asia. As objects made from exotic raw materials and using complex technologies, stone and glass beads are one type of prestige object from South Asia that were exchanged widely across Southeast Asia. This study examines beads from 12 sites in Cambodia and Thailand. Morphological and compositional analyses using LA-ICP-MS resulted in the identification of different bead types that were circulated in distinct exchange networks. Initially, beads were exchanged within a pre-existing South China Sea network. However, as trade with South Asia intensified in the late Iron Age, exchange networks in Southeast Asia expanded, with an increase in the quantities of beads circulated. These results show the utility of studying beads as a means of examining trade and emerging socio-political complexity. Lastly, in considering evidence for control over the exchange of beads, I propose looking to an emerging state in the Mekong Delta.
The aim of this article is to characterise the present state of knowledge and outstanding problems of the Deccan. A description of the physical features, stratigraphy and age constraints on volcanism is followed by sections covering the Deccan's relationship to plate tectonics and the petrological-geochemical characteristics of the rocks and their petrogenesis. The final section discusses the relationship between the Rajmahal and Deccan traps and the possible link between the Deccan traps and Cretaceous-Tertiary extinctions. -A.W.Hall
The Indian subcontinent is blanketed with the remnants of at least five continental flood basalt provinces ranging in age from the Middle Proterozoic to the Late Cretaceous-Early Tertiary. Not surprisingly, the youngest of these, the Deccan plateau (derived from a Sanskrit word meaning “south” or “southern”) is by far the best-preserved and most extensive, presently occupying some half a million square kilometers of western and central India and southernmost Pakistan (Fig. 1). Until quite recently comparatively little was known about the geology of the body of this vast province, save that it was comprised of thick successsions of nearly flat-lying, subaerially erupted, predominantly tholeiitic lava flows, at least some of which were traceable for distances of more than 100 km. Neither the gross features nor the details of flow stratigraphy, eruptive source locations, regional structure, or chemical and isotopic variations were understood; ages and age distributions were imperfectly known, and ideas on mantle sources and petrogenesis remained largely in the realm of speculation. Up to and throughout the 1970’s it was not unusual to see arguments in the literature that relied heavily on pioneering studies done in the 1800’s or early years of this century. A voluminous amount of work did exist on the scattered, small alkalic and acidic intrusive suites dotting the western and northern areas of the Deccan. Although lithologically distinctive in a sea of tholeiitic lava, they are volumetrically insignificant and for the most part appear to post-date the main phase of eruptive activity. Studies of these restricted occurrences therefore were unable to shed much light on the fundamental nature of the plateau itself. Only in the last several years have detailed, systematic investigations been conducted on a regional scale, utilizing a combination of modern methods.
Iron Age agate and carnelian beads found in Southeast Asia have long been assumed to be Indian imports, often featuring in diffusion-orientated theories of Southeast Asian state development that cite Indian influence as a major causal factor. The origin of these beads is tested here, through a pioneering non-destructive geochemical sourcing study of carnelian beads and potential source material. Our results suggest that many of these beads do not derive from India. Instead, a complex multi-source origin, involving some local Southeast Asian manufacture, appears likely. This finding further erodes the already crumbling foundation of diffusion-based theories of Southeast Asian state development. An alternative, regionally focused, approach to the study of these beads is recommended using geochemical analysis to help trace their trade within Southeast Asia. This will enable a better understanding of their role in, and impact upon, existing prestige goods exchange networks within the region.
We report the results of LA-ICP-MS analysis of 402 quartzite samples representing 48 collection loci in the Upper Gunnison Basin (UGB), Colorado and determine the extent to which the sources can be geochemically discriminated from one another using this non-destructive technique. The ability to differentiate among the sources would open the door to provenance studies of the quartzite chipped-stone tools and debitage that constitute 95% or more of most of the 3000-plus prehistoric site assemblages documented in the UGB. Our samples represent prehistorically quarried and non-quarried quartzite sources, including outcrop (primary) and gravel (secondary) deposits. The results reveal spatial and chronological trends in quartzite elemental composition that can be exploited for provenance determinations of quartzite artifacts from UGB sites, albeit using an assemblage-based sourcing strategy that differs from the familiar approach of “matching” obsidian artifacts to their statistically likeliest geological source. We offer a preliminary version of a sourcing protocol for UGB quartzite.
Thermoluminescence (TL) is routinely used to date heated lithic artefacts which mostly consist of silex (a mixture of amorphous opal and microcrystalline chalcedony). Analytical investigations of bulk samples confirmed that these materials contain considerable concentrations of radioactive elements, generating an internal dose rate contribution. Common dosimetric models assume the latter to be homogeneous throughout the sample. If this assumption would prove invalid, this will result in systematic errors in the calculated age, especially in the course of so called 'hot spots' of α-emitters (and associated local changes in α-sensitivity) and the dose response characteristics of α-radiation. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of 22 silex samples are presented here, quantifying element concentrations at several tens analytical spots per sample. Along with radioactive elements (K, Rb, U, Th), another 21 major, minor and trace elements were measured in order to allow characterization of the impurities present in most of the samples. The dataset provides a detailed picture of the spatial distribution of radionuclides and hence of the uniformity of the internal α- and β-dose rate. It is shown that the silex itself mostly contains low amounts of K (<0.1 wt.%), U (<1.0 μg g -1) and Th (<0.4 μg g -1), and dosimetrically negligible Rb concentrations. Systematically higher concentrations are obtained by ICP-MS measurements of the bulk samples. This matches with the finding that impurities (veins, inclusions) often yield significantly elevated radionuclide concentrations, up to two orders of magnitude higher than the silex values. These veins and inclusions, for example Ca or Mg carbonates and Fe-Mn-oxy-hydroxides, lead to steep gradients mainly in the internal α-radiation field. Alternative approaches are required to account for the non-uniform internal dose rate and improve the reliability of TL dates of problematic samples.
Agates from the Bighorn district in Montana (USA), the so-called Dryhead area, and their adjacent host rocks have been examined in the present study. Analyses by XRD, polarizing microscopy, LA-ICP-MS, cathodoluminescence (CL), SEM and of oxygen isotopes were performed to obtain information surrounding the genesis of this agate type.
Investigations of the agate microstructure by polarizing microscopy and CL showed that chalcedony layers and macrocrystalline quartz crystals may have formed by crystallization from the same silica source by a process of self-organization. High defect densities and internal structures (e.g. sector zoning) of quartz indicate that crystallization went rapidly under non-equilibrium conditions. Most trace-element contents in macrocrystalline quartz are less than in chalcedony due to a process of 'self-purification', which also caused the formation of Fe oxide inclusions and spherules.
Although the agates formed in sedimentary host rocks, analytical data indicate participation of hydrothermal fluids during agate formation. Trace elements (REE distribution patterns, U contents up to 70 ppm) and CL features of agate (transient blue CL), as well as associated minerals (fluorite, REE carbonates) point to the influence of hydrothermal processes on the genesis of the Dryhead agates. However, formation temperatures
The use of discriminant function analyses (DFA) in archaeological and related research is on the increase, however many of the assumptions of this method receive a mixed treatment in the literature. Statisticians frequently use complex statistical models to investigate analytical parameters, but such idealised datasets may be hard to relate to “real-life” examples and the literature difficult to assess. Using two faunal datasets that are more typical of archaeological and related research, one comprised of size-corrected linear measurements of bovid humeri and another of 3D geometric morphometric (GMM) shape data of African monkey skulls, and two simulated datasets, we illustrate some of the most important but often ignored issues of DFA. We specifically show why it is paramount to address “over-fitting” by cross-validation when applying this method and how the probability of correctly classifying cases by chance can be properly and explicitly taken into account.
The interbedded chert and iron minerals of banded iron formation (BIF) provide an important window into the chemistry of the Precambrian ocean. Chert microbands have better preservation potential than the iron-rich bands but pose analytical challenges. The generally much lower concentration of trace elements in chert require better detection limits and make chert more susceptible to the influence of foreign materials such as ash or detritus. Without screening for chemical complexity, bulk chemical analyses may have limited significance. Here we report a new analytical protocol consisting of two steps. First it uses exploratory laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in situ analysis for identifying suitable chert areas to be sub-sampled for solution ICP-MS analysis. Second, the subsampled chert is digested and dried down, volatilizing the bulk of the matrix as SiF4. The solution can then be admitted to the ICP-MS at much lower dilution factors than common rock samples, resulting in detection limits for many of the rare earth elements at double or single digit ppt levels. This approach produces high quality trace element data even for cherts with exceedingly low trace element contents. Significantly, such data approach primary chemical composition of the BIF better than conventional bulk analysis. It is also demonstrated, through selective digestions, that the most common types of mineralogical heterogeneity in cherts – carbonate and iron-oxide minerals – have minimal effect on the REE+Y composition, at least in studied cherts from the Abitibi Greenstone Belt. The proposed combination of techniques will allow future studies of more refined trace element chert geochemistry, providing a better understanding of Precambrian oceans and BIF deposition.
Trace elemental analysis of ancient ceramics has been proven a very useful tool for tracing the circulation of this material. Instrumental neutron activation analysis (INAA) was for years the analytical technique of choice to measure the composition of ceramics because of the large number of elements it could determine and its good sensitivity. Lately, a few publications have shown that laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) could provide similar results as INAA more quickly and at lower cost. A protocol has been developed to determine 51 elements using LA-ICP-MS and tested it on Wari period ceramics previously analyzed using INAA. We show how INAA and LA-ICP-MS analysis lead to the same conclusion in terms of sample groupings.
A comparison between the compositions determined by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) from two different laboratories on 52 ancient beads recovered in Africa was undertaken. Single point and raster samplings by the laser ablation systems were used. Although similar results were obtained using the two approaches on most of the beads, raster sampling was found more sensitive to corrosion than single point sampling. The impact of corrosion on the results and on their interpretation is discussed. Depending on the types of glass, group attribution is variably affected.
Microanalytical trace element techniques (such as ion probe or laser ablation ICP-MS) are hampered by a lack of well characterized, homogeneous standards. Two silicate glass reference materials produced by National Institute of Standards and Technology (NIST), NIST SRM 610 and NIST SRM 612, have been shown to be homogeneous and are spiked with up to sixty one trace elements at nominal concentrations of 500 mu g g(-1) and 50 mu g g(-1) respectively. These samples (supplied as 3 mm wafers) are equivalent to NIST SRM 611 and NIST SRM 613 respectively (which are supplied as 1 mm wafers) and are becoming more widely used as potential microanalytical reference materials. NIST however, only certifies vp to eight elements in these glasses. Here we have compiled concentration data from approximately sixty published works for both glasses, and have produced new analyses from our laboratories. Compilations are presented for the matrix composition of these glasses and for fifty eight trace elements. The trace element data includes all available new and published data, and summaries present the overall average and standard deviation, the range, median, geometric mean and a preferred average (which excludes all data outside +/- one standard deviation of the overall average). For the elements which have been certified, there is a good agreement between the compiled averages and the NIST data. This compilation is designed to provide useful new working values for these reference materials.
The Corning Museum of Glass
- R H Brill
Brill, R.H., 1999. Chemical Analyses of Early Glasses, Vol. 2. The Corning Museum of Glass,
New York.
Classifying chalcedony: its many varieties are an ongoing debate. Rock and Gem
- G Butler
Butler, G., 1995. Classifying chalcedony: its many varieties are an ongoing debate. Rock
and Gem, November, 60-61.
Trade, exchange, and, sociopolitical development in iron age (500 BC-AD 500) mainland southeast Asia: an examination of stone and glass beads from Cambodia and Thailand
- A K Carter
Carter, A.K., 2013. Trade, exchange, and, sociopolitical development in iron age (500 BC-AD 500) mainland southeast Asia: an examination of stone and glass beads from
Cambodia and Thailand (Ph.D.) Department of Anthropology. University of
Wisconsin-Madison.
Indian Agate Beads. Lapis Route Books
- P Francis
Francis Jr., P., 1982. Indian Agate Beads. Lapis Route Books, Lake Placid, NY.
Ancient Trades and Cultural Contacts in Southeast Asia. The Office of the National Culture Commission
- P Francis
Francis Jr., P., 1996. Beads, the bead trade, and state development in Southeast Asia. In:
Chutiwongs, N. (Ed.), Ancient Trades and Cultural Contacts in Southeast Asia. The Office of the National Culture Commission, Bangkok, pp. 139-160.