Showing papers on "Bronze published in 2017"

Female exogamy and gene pool diversification at the transition from the final neolithic to the early Bronze Age in central Europe

Abstract: Human mobility has been vigorously debated as a key factor for the spread of bronze technology and profound changes in burial practices as well as material culture in central Europe at the transition from the Neolithic to the Bronze Age. However, the relevance of individual residential changes and their importance among specific age and sex groups are still poorly understood. Here, we present ancient DNA analysis, stable isotope data of oxygen, and radiogenic isotope ratios of strontium for 84 radiocarbon-dated skeletons from seven archaeological sites of the Late Neolithic Bell Beaker Complex and the Early Bronze Age from the Lech River valley in southern Bavaria, Germany. Complete mitochondrial genomes documented a diversification of maternal lineages over time. The isotope ratios disclosed the majority of the females to be nonlocal, while this is the case for only a few males and subadults. Most nonlocal females arrived in the study area as adults, but we do not detect their offspring among the sampled individuals. The striking patterns of patrilocality and female exogamy prevailed over at least 800 y between about 2500 and 1700 BC. The persisting residential rules and even a direct kinship relation across the transition from the Neolithic to the Bronze Age add to the archaeological evidence of continuing traditions from the Bell Beaker Complex to the Early Bronze Age. The results also attest to female mobility as a driving force for regional and supraregional communication and exchange at the dawn of the European metal ages.

Revisiting lead isotope data in Shang and Western Zhou bronzes

Abstract: Lead is a major component of Chinese ritual bronze vessels. Defining its sources and usage is thus highly significant to understanding the metal industries of the Chinese Bronze Age. A new, simplified method has been developed for examining data, thereby providing insight into diachronic change in the origins of lead sources used in artefacts. Application of this method to the existing corpus of lead isotope data from the Erlitou (c. 1600 BC) to the Western Zhou (c. 1045�771 BC) periods reveals changes in the isotope signal over this time frame. These changes clearly reflect shifts in the sourcing of ores and their use in metropolitan foundries. Further data are required to understand these complex developments.

Bronze Age metal circulation in China

Abstract: The Shang (c. 1500–1045 BC) and Zhou dynasties (c. 1045–771 BC) of China are famous for their sophisticated ritual bronze vessels. Sourcing the leaded tin-bronze has, however, proved to be a challenge. A new systematic approach to metal chemistry uses trace elements and isotopes to characterise the underlying circulation pattern. It reveals the complexity of the copper sources on which the late Shang capital at Anyang depended for its bronzes, suggesting the transport of copper from distant regions in the south, on the Yangtze, and from north-east China. The new interpretational system furthers our understanding of the network on which successive Chinese dynasties depended for copper, lead and tin, and attempts to give equal weight to the archaeological and chemical data.

Laser cladding of phosphor bronze

Abstract: Phosphor bronze is a suitable bearing material because of its good fatigue strength and excellent wear properties under corrosive conditions, high temperatures and high loads. Bronze is usually continuously cast as bar or tube and machined into bushes, cam followers, washers or other bearing components. It is common to mount bronze bushes around shafts by means of warm shrink fitting. Laser Cladding is a manufacturing process to generate a dense a metallurgical bonded coating over a substrate and it can be employed to deposit a phosphor bronze coating directly over a shaft improving its wear properties. In this paper, the feasibility of the Laser Cladding to produce phosphor bronze coatings on alloy steel is demonstrated. Suitable processing parameters to generate phosphor bronze coatings are presented. The hardness of the bronze coating obtained is 172 ± 12 HV, 56% higher than the one reported for cast bronze. Finally, Laser Cladding is proposed as a method to create a bronze surface in an area of a shaft as a substitute of warm shrink fitting of machined bronze bushes.

Welding parameters analysis and microstructural evolution of dissimilar joints in Al/Bronze processed by friction stir welding and their effect on engineering tensile behavior

Abstract: The effect of welding parameters on the joint properties in dissimilar friction stir welding (FSW) between AA5052 alloy and C22000 Bronze alloy was investigated in this study. The FSW process was carried out at rotational speeds of 800, 1000, 1250 and 1400 revolutions per min (rpm) and welding speeds of 20, 31.5 and 50 mm/min. Results showed that welding under 800 rpm is impossible due mainly to the lack of heat input as well as the appearance of tunnel defects. Results also showed that the increase of rotational speed causes an increase in the fraction of intermetallic layer and the appearance of ring/layer pattern in nugget zone. As well, it was found from EBSD analysis that the difference in stacking fault energy of Aluminum and Bronze leads to different dynamic recrystallization behavior in Aluminum and Bronze parts undergoing equivalent amount of thermo-mechanical process in the nugget zone. Mechanical strength showed that there is a direct relation between the amount of interface of the base metal impressed by welding parameters and the mechanical strength of the joints. Finally, it was found that the maximum amount of ultimate tensile strength (UTS) for the joint was about 64% of the UTS of the Aluminum base metal. This was achieved through changing the welding parameters such that the interface length between the base metals was the highest and in contrast the interacting intermetallic layer, which acts as a bond between the base metals, was the narrowest.

Portable XRF on Prehistoric Bronze Artefacts: Limitations and Use for the Detection of Bronze Age Metal Workshops

Abstract: Abstract Two different scientific analyses-one destructive and one non-destructive-were conducted on two separate groups of bronze ornaments dating from 1500-1100 BC to investigate, amongst other traits, the metal composition of their copper-tin alloys. One group of artefacts was sampled, and polished thin sections were analysed using a scanning electron microscope (SEM). Results from the corrosion crust of copper-tin alloys, and the change measured within the elemental composition from the bulk metal to the surface, greatly influenced the interpretation of the second data set, which was measured using a handheld X-ray fluorescence (XRF) device. The surface of corroded bronze ornaments consists mostly of copper carbonates, oxides, and chlorides. Chemical processes, such as decuprification, change the element composition in such a manner that the original alloy cannot be traced with a non-destructive method. This paper compares the results of both investigations in order to define the possibilities and limits of non-destructive XRF analyses of corroded bronze artefacts.

Determination of the Tin Stable Isotopic Composition in Tin‐bearing Metals and Minerals by MC‐ICP‐MS

Abstract: This study uses MC-ICP-MS for the precise analysis of the stable tin isotopic composition in ore minerals of tin (cassiterite, stannite), tin metal and tin bronze. The ultimate goal is to determine the provenance of tin in ancient metal objects. We document the isotope compositions of reference materials and compare the precision of different isotope ratios and the accuracy of different procedures of mass fractionation correction. These data represent a base with which isotopic data of future studies can be directly compared. The isotopic composition of cassiterite and stannite can be determined after reduction to tin metal and bronze, respectively. Both metals readily dissolve in HCl, but while the solutions of tin metal can be directly measured, the bronze solutions must be purified with an anion exchanger. The correction of the mass bias is best performed with an internal Sb standard and an empirical regression method. A series of Sn isotope determinations on commercially available mono-element Sn solutions as well as reference bronze materials and tin minerals show fractionations ranging from about −0.09‰ to 0.05‰/amu. The combined analytical uncertainty (2s) was determined by replicate dissolutions of reference materials of bronze (BAM 211, IARM-91D) and averages at about 0.005‰/amu.

Pulsed infrared thermography applied to quantitative characterization of the structure and the casting faults of the Capitoline She Wolf

Abstract: Pulsed infrared thermography was applied to the analysis of the Capitoline She Wolf bronze statue, in the collection of the Musei Capitolini in Rome. We show how it can be used to study the bronze alloy properties and several subsurface and structural features of the statue such as casting faults and repairs providing information useful to recover the steps of the manufacturing process. In particular, the thermal diffusivity of the alloy was determined and quantitative evaluations were carried out concerning the thickness of the bronze in various parts of the statue, the depth of cavities originating from air bubbles in the casting melt and the profile of the contact area of some patches applied to mend gaps left after the casting process. Finally the obtained thermal diffusivity value was discussed in relation to the actual bronze composition of the She Wolf statue and it was shown to be consistent with the trend of values expected for different copper alloy compositions.

Hunting Warriors: The Transformation of Weapons, Combat Practices and Society during the Bronze Age in Ireland

Abstract: Warfare is increasingly considered to have been a major field of social activity in prehistoric societies, in terms of the infrastructures supporting its conduct, the effects of its occurrence, and its role in symbolic systems. In the Bronze Age many of the weapon forms that were to dominate battlefields for millennia to come were first invented—shields and swords in particular. Using the case study of Ireland, developments in Bronze Age warfare are traced from the Early to the Late Bronze Age. It is argued that during this period there was a move from warfare that made use of projectiles and impact weapons to warfare that used both defensive and cutting weapons. This formed the basis for a fundamental reorganization in combat systems. This in turn stimulated change in the social organization of warfare, including investment in material and training resources for warriors and the development of new bodily techniques reflecting fundamental changes in martial art traditions. Metalwork analysis of bronze weapons and experimental archaeology using replicas of these are used to support this position. The article explores how developments in fighting techniques transformed the sociality of violence and peer-relations among warriors and proposes that these warriors be regarded as a category of craft specialist exerting significant social influence by the Late Bronze Age.

Copper content in anthropogenic sediments as a tracer for detecting smelting activities and its impact on environment during prehistoric period in Hexi Corridor, Northwest China

Abstract: The Hexi Corridor of northwestern China was a principal axis of cultural interchange between eastern and western Eurasia during the prehistoric and historic epochs. Neolithic groups began dense settlements in Hexi Corridor after 4300 BP with millet crops and polychrome pottery from north China and bronze from Central Asia around 4000 BP accompanied by wheat, barley, and sheep. The impact of these activities on the environment during the late Neolithic and Bronze Age is not clearly understood. Therefore, we analyzed the Cu concentrations of samples collected within cultural layers of anthropogenic sediments from 17 Late Neolithic and Bronze Age sites located within the Hexi Corridor. The Cu content is reported in view of the archaeological and paleoclimatic research undertaken in the area. Our results enabled us to explore the variety of human impact on the environment before and after the introduction of bronze technology into Hexi Corridor. During 4300–4000 BP, Cu concentrations of the anthropogenic sedi...

Eastern Mediterranean Mobility in the Bronze and Early Iron Ages: Inferences from Ancient DNA of Pigs and Cattle

Abstract: The Late Bronze of the Eastern Mediterranean (1550-1150 BCE) was a period of strong commercial relations and great prosperity, which ended in collapse and migration of groups to the Levant. Here we aim at studying the translocation of cattle and pigs during this period. We sequenced the first ancient mitochondrial and Y chromosome DNA of cattle from Greece and Israel and compared the results with morphometric analysis of the metacarpal in cattle. We also increased previous ancient pig DNA datasets from Israel and extracted the first mitochondrial DNA for samples from Greece. We found that pigs underwent a complex translocation history, with links between Anatolia with southeastern Europe in the Bronze Age, and movement from southeastern Europe to the Levant in the Iron I (ca. 1150-950 BCE). Our genetic data did not indicate movement of cattle between the Aegean region and the southern Levant. We detected the earliest evidence for crossbreeding between taurine and zebu cattle in the Iron IIA (ca. 900 BCE). In light of archaeological and historical evidence on Egyptian imperial domination in the region in the Late Bronze Age, we suggest that Egypt attempted to expand dry farming in the region in a period of severe droughts.

Determination on the Effect of Tin Content on Microstructure, Hardness, Optimum Aging Temperature and Aging Time for Spinodal Bronze Alloys Cast in Metal Mold

Abstract: A study was conducted to determine the effect of tin content on microstructure, hardness, optimum aging temperature and aging time of spinodal bronze alloys cast in metal mold. Copper, nickel and tin with appropriate compositions were melted in an electric furnace under argon atmosphere and were cast into metal molds. The cast specimens were solutionized at 825 °C for 10 h and were aged at 250, 300, 350, 400 and 450 °C for 1–5 h. The solutionized and aged specimens were subjected for microstructural evaluation and hardness testing. It was observed that the grain boundary precipitates form upon over-aging. The peak hardness increases with increase in tin content from 4 to 12 wt% in solutionized and aged condition. The peak aging time was found to remain a constant with increase in Sn content. The optimum aging temperature and aging time were also determined for spinodal bronze alloys cast in metal mold.

Arrows of Power from Brittany to Denmark (2500–1700 BC)

Abstract: This article presents a comparative study of the arrowheads found in graves dating to between 2500 BC and 1700 bc in north-west France, southern Britain and Denmark. The aim is to characterise their modes of production and functions during a period which successively sees the introduction of copper then bronze metallurgy, the former accompanying the appearance of Bell Beaker pottery and associated practices in these areas. Several modes of production are proposed, from individual manufacture by Bell Beaker-using warriors to specialist production for elite use during the Early Bronze Age. Over and above their function as weapons – arguably associated more with interpersonal combat than with hunting – arrowheads served to portray and emphasise the social status of the individuals. In the case of the Early Bronze Age Armorican arrowheads, they should be regarded as ‘sacred’ objects, made for display and enhancing the power of the chiefs. Lastly, arrows are placed in the broader perspective of major trends affecting Europe during the Bell Beaker period and then the Early Bronze Age, while the distribution of arrowheads with slanted barbs suggests the operation of an Atlantic cultural complex.

Metalworking at Megiddo during the Late Bronze and Iron Ages

Abstract: Over the years, the excavations at Tel Megiddo have yielded numerous metal objects, as well as evidence of metallurgical activity. Here we show that metalworking was practiced continuously in the southeastern sector of the tell from the end of the Middle Bronze Age until Iron IIB. During this time, one can trace changes in the production processes, including the introduction of ironworking alongside the continuation of bronzeworking. Dating and contextualizing this significant development is crucial to understanding the social, economic, and geo-political circumstances under which it occurred. The evidence that we present shows that iron production was accompanied by a substantial increase in iron, as expressed on the level of consumption. This occurred during Iron IIA, concurrent with cultural and political changes, expressed, inter alia, in the architectural layout of the city and its cultic practices. Possible evidence that local bronzesmiths may have been partially engaged in iron production already in Iron Age I is found in the form of a hoard recently unearthed at Megiddo, although iron-working debris has not yet been found in contemporary contexts. The fact that metalworking and exploitation of metal resources are strongly tied to political power and social infrastructure is well accepted.1 Especially intriguing is the introduction and gradual preeminence of iron over bronze (which continued to be produced), a process that took place at the turn of the

Iron Age tin bronze metallurgy at Marlik, Northern Iran: an analytical investigation

Abstract: The archaeological excavations performed in 1961 and 1962 at the necropolis of Marlik (Gilan District, northern Iran) revealed important archaeological remains dating to Iron Age I and II periods (late second/early first millennium BCE). While the metal collection from Marlik includes various gold, silver and bronze objects and is considered one of the most significant finds of metal objects from the prehistoric Iran, the technological investigations discussed in this paper provide information on tin bronze objects only from Marlik. Both the composition and the microstructure of 25 copper alloy objects have been determined in order to achieve a better understanding of the metallurgical processes used in northern Iran from the second to the first millennium BCE. Experimental analyses were carried out using inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) and optical microscopy. The results demonstrated that the copper-base objects were made of the binary copper–tin alloy with variable tin contents. Other elements such as As, Ni, Pb, Zn and Sb were detected in minor/trace amounts. Variable tin content may be due to the application of an uncontrolled procedure to produce bronze alloy (e.g. co-smelting or cementation). Microscopic observations and microanalyses revealed the presence of numerous copper sulphide inclusions, lead globules and intermetallic phases scattered in the bronze solid solution. The microstructures seen in the bronze objects under study were varied and included worked/annealed or dendritic grain structures.

High-Pressure Synthesis of Fully Occupied Tetragonal and Cubic Tungsten Bronze Oxides

Abstract: A high-pressure reaction yielded the fully occupied tetragonal tungsten bronze K3W5O15 (K0.6WO3). The terminal phase shows an unusual transport property featuring slightly negative temperature-dependence in resistivity (dρ/dT<0) and a large Wilson ratio of RW=3.2. Such anomalous metallic behavior possibly arises from the low-dimensional electronic structure with a van Hove singularity at the Fermi level and/or from enhanced magnetic fluctuations by geometrical frustration of the tungsten sublattice. The asymmetric nature of the tetragonal tungsten bronze KxWO3-K0.6−yBayWO3 phase diagram implies that superconductivity for x≤0.45 originates from the lattice instability because of potassium deficiency. A cubic perovskite KWO3 phase was also identified as a line phase—in marked contrast to NaxWO3 and LixWO3 with varying quantities of x (<1). This study presents a versatile method by which the solubility limit of tungsten bronze oxides can be extended.

Egyptian Imperial Economy in Canaan: Reaction to the Climate Crisis at the End of the Late Bronze Age

Abstract: In this article we discuss four datasets that provide evidence for the expansion of grain growing in Canaan in the second half of the 13th century and the 12th century BCE: the faunal and flint records from Megiddo, the pollen diagram for the Sea of Galilee and the ancient DNA study of Bronze and Iron Age cattle in the Levant. Efforts to expand dry farming in Canaan were probably related to the dry climate event in the later phases of the Late Bronze Age, which has recently been detected in several pollen records from the Eastern Mediterranean. We discuss textual evidence related to drought and famine that struck the Near East at that time. We then suggest that the Egyptian administration in Canaan initiated the extension of dry farming in order to stabilise the situation in the southern and eastern fringe areas of the Levant and supply grain to areas in the northern Near East which, according to textual data, were badly afflicted by the climate crisis.

Effect of High Energy Milling Time of the Aluminum Bronze Alloy Obtained by Powder Metallurgy with Niobium Carbide Addition

Abstract: The aluminum bronze alloy is part of a class of highly reliable materials due to high mechanical strength and corrosion resistence being used in the aerospace and shipbuilding industry. It's machined to produce parts and after its use cycle, it's discarded, but third process is considered expensive and besides not being correct for environment reasons. Thus, reusing this material through the powder metallurgy (PM) route is considered advantageous. The aluminum bronze chips were submitted to high energy ball milling process with 3% of niobium carbide (NbC) addition. The NbC is a metal-ceramic composite with a ductile-brittle behaviour. It was analyzed the morphology of powders by scanning electron microscopy as well as particle size it was determined. X ray diffraction identified the phases and the influence of milling time in the diffractogram patterns. Results indicates that milling time and NbC addition improves the milling efficiency significantly and being possible to obtain nanoparticles.

The Bronze Age battlefield in the Tollense Valley, Northeast Germany : Conflict scenario research

Abstract: A comprehensive series of radiocarbon dates on human skeletal material was conducted to differentiate Bronze Age human remains from earlier or later river finds. The distribution of bronze finds in the Tollense Valley is even more extensive than that of Bronze Age skeletal remains. The Tollense Valley is situated in northeastern Germany, in the federal state of Mecklenburg-Western Pomerania, c. 120 km north of Berlin, c. 60 km south of the Baltic coast and c. 70 km west of the German-Polish border. The distribution of socketed arrowheads gets sparser from south to north in Germany and Europe; apart from the finds from the Tollense Valley, there are only 28 examples from Mecklenburg-Western Pomerania, and further to the north and northwest they are extremely rare. The starting point of research in the Tollense Valley was the hypothesis that the find layer with skeletal remains might result from a violent conflict.

Multianalytical study of corrosion layers in some archaeological copper alloy artefacts

Abstract: Corrosion layers in some copper and bronze archaeological objects from Haft Tappeh archaeological site, southwest Iran, were studied. For this purpose, optical microscopy, scanning electron microscopy with energy dispersive X-ray microanalysis, micro-Raman spectroscopy and X-ray diffraction methods were applied to observe corrosion stratigraphy and their characteristics as well as identification of chemical composition and phase determination of different corrosion layers. Based on optical and electron microscopy, three different corrosion strata were identified in cross section of different metallic objects including various red, green, white-grey powdery and dark internal compact layers. Scanning electron microscopy with energy dispersive X-ray microanalysis on different corrosion layers revealed that Cu, Sn and Cl are the main elements in the chemical composition of different layers. Tin-rich phases were detected in white-grey and dark layers that may be formed because of the internal oxidation of tin as well as the decuprification (selective dissolution of copper) phenomena occurring during long-term burial period in the soil. Also, the XRD and micro-Raman spectroscopy results proved that the main corrosion products are nantokite (CuCl), copper trihydroxychlorides and copper oxides. The combination of these analytical methods allows us to explore the surface and internal corrosion layers of the archaeological copper and bronze samples, and major interest is on studying their chemistry, microstructural properties and corrosion stratigraphy. Copyright © 2015 John Wiley & Sons, Ltd.

Shimao and Erlitou: new perspectives on the origins of the bronze industry in central China*

Abstract: Over the last five years, excavation of a large, stone, fortified site at Shimao, on the northern edge of the Loess Plateau in Shaanxi Province, China, has radically changed our understanding of the events that precipitated the development of the first bronze casting in central China at Erlitou (Figure 1). An international conference on the Shimao site, held at Shenmu in August 2016, explored many aspects of this major discovery.

Radiocarbon Assessment of Early Bronze Arad: The 20 Year Lifespan of Stratum II

Abstract: The rich remains from the Early Bronze II at Tel Arad have been interpreted as representing several centuries of activity. According to conventional wisdom, after the destruction of Stratum III by fire, Stratum II endured for about 150 years. However, high precision dates obtained for Stratum II as well as a subsequent destruction event suggest that rapid reconstruction took place in the span of one or two decades. The results point to a short duration of the EB II occupation in Arad and these are in agreement with the south Levantine radiocarbon chronology for the Early Bronze Age. They suggest that the end of the EB II occupation was synchronous with the 1st Egyptian Dynasty ruler Qaʿa.

EXCAVATIONS AT KURD QABURSTAN, A SECOND MILLENNIUM b.c. URBAN SITE ON THE ERBIL PLAIN 1

Abstract: Excavations at the 109 hectare site of Kurd Qaburstan on the Erbil plain in the Kurdistan Region of Iraq were conducted by the Johns Hopkins University in 2013 and 2014. The Middle Bronze Age (Old Babylonian period) is the main period of occupation evident on the site, and the project therefore aims to study the character of a north Mesopotamian urban centre of the early second millennium b.c. On the high mound, excavations revealed three phases of Mittani (Late Bronze) period occupation, including evidence of elite residential architecture. On the low mound and the south slope of the high mound, Middle Bronze evidence included domestic remains with numerous ceramic vessels left in situ. Also dating to the Middle Bronze period is evidence of a city wall on the site edges. Later occupations include a cemetery, perhaps of Achaemenid date, on the south slope of the high mound and a Middle Islamic settlement on the southern lower town. Faunal and archaeobotanical analysis provide information on the plant and animal economy of the second millennium b.c. occupations, and geophysical results have documented a thirty-one hectare expanse of dense Middle Bronze Age architecture in the northern lower town.

Examinations of a Bronze Ingot Made of Fahlore

Abstract: In Europe, the metallurgy of copper has been a tradition for thousands of years, which is also testified by relevant artifacts that can be found. A copper ingot of unknown origin was made available for the examinations. The surface of the ingot was characterized by a deposit of corrosion products from malachite and cuprite which could also be observed in cavities. XRF measurements resulted in Cu as the main component, up to 4 wt. % As, and 2.5 wt. % S, as well as smaller quantities of Sb, Ni, Fe, and Ag. This composition suggests the production from fahlores. A typical cast structure with copper dendritic areas and concentrations of the accompanying elements in the interdendritic areas could be observed. Delafossite crystals (Cu3Ni2SbO6) were verified on the ingot's top side (melt in contact with the air). The ingot is thus composed of an As bronze with a complex microstructure consisting of solid solutions, intermetallic phases, and sulfides.