1,001 research outputs found
Optical and Scanning Electron Microscope Images of Metallurgical Debris from Mtsvane Gora
No full textThis dataset contains optical microscope (reflected light images of polished sections) and scanning electron microscope (SEM) images of metallurgical debris from the archaeological site of Mtsvane Gora in southern Georgia
Iron in copper metallurgy at the dawn of the Iron Age: insights on iron invention from a mining and smelting site in the Caucasus
No full textData on analyses of slags, ores, and fluxes is provided in the supplementary information and in an open access dataset published on the Harvard Dataverse (Erb-Satullo and Klymchuk, 2025).
Appendix A. Supplementary data. Supplementary data to this article can be found on the publisher web page.Despite enormous interest in the origins of the iron, the world's quintessential industrial metal, the technological foundations of the invention and innovation of extractive iron metallurgy remain unclear. While fundamental aspects of geology and thermodynamics favor a model for the invention of iron by copper smelters, empirical archaeological evidence to support this model is lacking. Reanalysis of the smelting workshop at Kvemo Bolnisi, originally published as an iron smelting site in the 1960s and dated to the late 2nd millennium BC, offers insights by which copper smelters recognized and experimented with iron oxides. Chemical and microscopic analysis of slags and minerals samples via optical microscopy and SEM-EDS conclusively shows that metalworkers at the site were smelting copper rather than iron. However, our analyses, coupled with a reassessment of the excavation report, show that iron oxides were deliberately stockpiled and added to the furnace as a separate component of the charge to flux the silica-rich host rock. These discoveries make Kvemo Bolnisi arguably the earliest unequivocal example of the deliberate use iron oxide fluxes in copper metallurgy. The knowledge and behaviors reflected in the Kvemo Bolnisi copper smelting technology have important implications for theories about the invention of iron metallurgy by copper smelters.This research was supported by the British Institute at Ankara, the Gerda Henkel Foundation (AZ 33/F/22), and the American Research Institute of the South Caucasus, and the Teschmacher Fund.Journal of Archaeological Scienc
Archaeomaterials, Innovation, and Technological Change
No full textThe field of archaeomaterials research has enormous potential to shed light on past innovation processes. However, this potential has been only partially recognized outside its immediate practitioners, despite the fact that innovation and technology change are topics of enduring interest in archaeology and the broader social sciences. This review explores the relationship between archaeomaterials research and the interdisciplinary study of innovation, and maps out a path toward greater integration of materials analysis into these discussions.
To foster this integration, this review has three aims. First, I sketch the theoretical landscape of approaches to the study of innovation in archaeology and neighboring disciplines. I trace how theoretical traditions like evolutionary archaeology have influenced archaeomaterials approaches to questions of technological change while also highlighting cases where work by archaeomaterials researchers anticipated trends in the anthropology of technology. Next, I distill a series of core concerns that crosscut these different theoretical perspectives. Finally, I describe examples where archaeomaterials research has deepened scholarly understanding of innovation processes and addressed these core questions. The future of archaeomaterials research lies in engagement with these broader discussions and effective communication of the contributions that materials analysis can make to building a comparative understanding of innovation processes
Aggregation Properties of the Chromonic Liquid Crystal Benzopurpurin 4B
No full textUnlike solids, which have both positional and orientation order, and liquids, which have no molecular organization, liquid crystals have have a degree of orientation order while still flowing like liquids. This unusual combination of properties makes them especially useful in technological applications. In certain lyotropic liquid crystals, molecular aggregates forming in solution orient along the same axis rather than individual molecules themselves. We studied this aggregation process in the chromonic liquid crystal Benzopurpurin 4B (BPP), a textile dye. In order to study the process of aggregation, we used dynamic light scattering on a range of different solutions to determine aggregate size and shape, the concentration needed for aggregate formation, and their response when heated. Results indicate that large anisotropic aggregates form in solution starting in the 0.11-0.12 wt% concentration range, but then grow in size as the concentration is increased. This type of aggregation behavior differs from other chromonic liquid crystals in that aggregation only begins above a certain concentration. On the other hand, amphiphillic aggregates, which also form only above certain concentration, do not grow in size. Therefore, BPP behaves differently than both more typical chromonic aggregates and amphiphillic systems. Since BPP comes with several different salt impurities, we developed a purification process using dialysis to obtain solutions of pure BPP. By reintroducing sodium salts in known concentrations and making phase measurements at different temperatures, we determined the salt effects on the formation of aggregates. Results for BPP paralelled a similar study [12] on disodium chromogylcate, with the addition of salt increasing the temperatures at which the liquid crystal phase can exist. Given the differences in aggregation behavior between these two compounds, these findings contribute to a more general understanding of how salt effects chromonic aggregation
The innovation and adoption of iron in the ancient Near East
No full textThis review synthesizes field research, textual analysis, and archaeometric data to evaluate different explanations for the spread of iron in the ancient Near East. Current evidence supports an Anatolian origin for extractive iron metallurgy on a limited scale sometime in the early 2nd millennium BC. However, the first major expansion of iron, both in Anatolia and across the wider Near East, occurred in the late second and early first millennium BC. Explanations that place iron adoption within its broader social context are favored over those that consider material or geological properties in isolation. A recurring theme is the importance of comparative analysis, both geographically and between the iron and bronze economies, to explore how social, political, and economic conditions affected adoption patterns
Chapter 43: Materials analysis of ceramics
No full textThe versatility and geological ubiquity of clay materials have meant that humans have adapted it to a wide range of different purposes, from building materials to tools for storage, transport, cooking, and eating. Archaeological ceramics range from mundane everyday wares to exquisite pieces of craftsmanship available only to the highest elites. Ceramic ethnoarchaeology has documented a wide range of approaches to clay processing, involving the removal and addition of constituents, as well as homogenization and transformation of raw materials through ageing or ‘souring’ of clays to improve their properties. Most laboratory analyses of ceramic materials can be grouped into three broad categories: compositional analyses, microstructural analyses, and macrostructural analyses. The presence of optical activity in the clay groundmass, when viewed in thin section under crosspolars, suggests a firing process that preserved the crystalline structure of clay minerals and did not result in extensive vitrification
Mechanistic Investigations into the Palladium-Catalyzed Decarboxylative Allylic Alkylation of Ketone Enolates Using the PHOX Ligand Architecture
No full textPalladium-catalyzed asymmetric allylic alkylation has become a large and important field for chemical synthesis. Many methodologies in this field offer mild conditions under which challenging and important molecular features can be reliably synthesized, including chiral all-carbon quaternary stereocenters. As a result, palladium- catalyzed asymmetric allylic alkylation has found significant use in total synthesis, and growing use in industry. While the general process of palladium-catalyzed asymmetric allylic alkylation has been studied for decades, there have been a number of recent modifications and developments, such as asymmetric versions of decarboxylative allylic alkylation procedures that are not yet well understood. The development of future implementations and improvements to palladium-catalyzed asymmetric allylic alkylation and related methodologies is expected to be facilitated by a better understanding of these more recent developments, and thus further mechanistic investigation is warranted.
Reported herein is a set of investigations into the palladium-catalyzed decarboxylative asymmetric allylic alkylation of ketone enolates using the PHOX ligand architecture. By monitoring the reaction via 31P NMR, a series of previously unidentified key intermediates is discovered. Two representatives of these key intermediates are isolated and characterized. The solution behavior of these species under reaction-like conditions is studied along with a few novel and related complexes. The role of these intermediates and their impact on the behavior of the reaction and product formation is discussed. Previously confounding experimentally observed behavior for this methodology is rationalized via the properties elucidated for these discovered intermediates.</p
Technological rejection in regions of early gold innovation revealed by geospatial analysis
No full textIn research on early invention and innovation, technological “firsts” receive enormous attention, but technological “lasts”—instances of abandonment and rejection—are arguably more informative about human technological behavior. Yet, cases of technological discontinuance are largely ignored in studies of early innovation, as the lack of robust datasets makes identification and analysis difficult. A large-scale geospatial analysis of more than 4500 gold objects from the Caucasus, an early center of gold innovation, shows a precipitous decline at 1500 BC in precisely the places with the earliest global evidence of gold mining (c. 3000 BC). Testing various causal models reveals that social factors, rather than resource limitations or demographic disruption, were the primary causes of this rejection. These results indicate that prior models of technological rejection and loss have underestimated the range of conditions in which they can occur, and provide empirical support for theories of innovation that reject notions about the linearity of technological progress.Scientific Report
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Metal Production in the Land of the Golden Fleece: Economic Organization and Technological Change in the South Caucasus, 1500-500 BC
No full textAnalyzing the causes and consequences of technological change is essential not only for the reconstruction of ancient social dynamics, but also for understanding how present-day societies confront the process of innovation. A central issue in the study of innovation is the effect of existing sociotechnical systems on the development of new technologies. In studying the emergence of iron technologies in the Near East, many scholars have theorized about the relationship between bronze and iron, comparing their relative geological availability, organization of production, and modes of distribution in an attempt to explain the rise of iron. The Caucasus is an ideal place to explore the impact of a well-established, large-scale bronze industry on the development of iron technology. Drawing on both social constructionist approaches to technology and theories of innovation diffusion, this dissertation considers whether established traditions of metallurgical practice engendered conservatism, or whether the existence of communities of metalworkers skilled in pyrotechnology stimulated the emergence and spread of iron.
Field survey, test excavation, laboratory analysis, and museum research were undertaken to explore how bronze production influenced the adoption of iron in the southeastern Black Sea region, known as Colchis by the ancient Greeks. Field survey of metal production landscapes revealed a highly dispersed distribution of small copper and iron smelting sites. Radiocarbon dating of these sites showed that copper smelting remains clustered in the period 1300-800 BC, while the earliest direct evidence for iron production comes from the mid-late 1st millennium BC. A detailed reconstruction of the technologies of iron and copper smelting, based on optical microscopy (reflected and transmitted light), scanning electron microscopy, and chemical analysis (SEM-EDS, pXRF, and WDS-XRF), highlighted specific techniques in the practice of copper smelting that would have facilitated learning and aided the spread of iron technologies. The integration of spatial and chemical data using GIS showed that there was little direct coordination of production activities between sites. The highly dispersed character of all stages of bronze production suggests that, in spite of its large aggregate scale and shared technological koiné, the industry operated in the absence of an overarching authority. This mode of production contrasts with other areas of the Near East, where contemporary copper smelting landscapes show a correlation between centralization, scale, and top-down control.
These results have significant implications for the rise of iron. A reexamination of its chronology in Colchis shows that iron was adopted following a massive expansion of bronze production. The existence of a community of practice based on common traditions of bronze manufacturing likely inhibited the early spread of iron in the region, but resulted in relatively rapid adoption once it was accepted as a culturally appropriate material. During the 8th-6th centuries BC, centralization of social networks through collective grave rituals and the emergence of sanctuary sites created an environment of elite competition and public display of metal wealth, accelerating the adoption of new metals. The result is that the earlier tradition of bronze production was neither purely inhibiting nor purely encouraging of innovation. Rather, its influence shifted, perhaps abruptly, sometime after 800 BC. Traditions of technical knowledge facilitated the rapid spread of iron use, but these effects were contingent upon important shifts in broader social and ritual practices. This research demonstrates that the influence of complex technical systems on innovation is not constant, and that seemingly minor shifts in social relations can abruptly alter the pace and pattern of technological change.AnthropologyCopper; Bronze; Iron; Craft Production; Technology; Landscape Archaeology; Geographic Information Systems; Materials Analysis; Microscopy; Caucasus; Black Se
Alloys from Anau: The Manipulation of Metallic Properties in 3<sup>rd</sup>Millennium B.C. Southern Central Asia
No full textABSTRACTMetallography, chemical analysis, and microhardness testing of copper-alloy objects from Anau, Turkmenistan (c. 3000-2400 B.C.), were undertaken to determine how technological choices influenced the properties of the finished objects. Additionally, this analytical program assessed the position of the Anau metals in the development of metallurgy in southern Central Asia. Metallographic analysis of three bladed objects, all copper-arsenic alloys with 1% to 5% arsenic, showed that their edges had been cold-worked to a greater or lesser degree to create a blade that maintained a sharp edge, but also had flexibility to withstand impacts. Microhardness testing confirmed that the blade edges had a higher hardness than the interior metal. One of the objects had sulfur-rich inclusions in the metal matrix, suggesting the original charge had at least some sulfide ore. Conversely, a curved rod, made from a copper-lead-tin alloy, was cast to shape and showed no additional working of the metal. Lead, visible as black particles in the microstructure, was likely added to make the molten metal flow more easily. The metallographic and chemical analyses showed that the Anau objects fit into the tradition of Southern Central Asian metallurgy, though the presence of tin in objects of this period is more rare here than in later periods. Anau smiths displayed an ability to manipulate both physical and chemical properties of metal in order to produce functional objects with optimal characteristics.</jats:p
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