Special alloys from remote frontiers of the Shang Kingdom: scientific study of the Hanzhong bronzes from southwest Shaanxi, China

More than 200 bronze objects found in Hanzhong, southwest Shaanxi Province, China, a frontier region of the Shang Kingdom during the Shang dynasty, have been analysed for their composition and microstructure. Forty-three typologically distinct, and probably culturally indigenous, items have been found to be compositionally distinctive as well. This paper presents analytical results of the two types of local Hanzhong bronzes, namely the sickle-shaped and sceptre-shaped objects. Three special alloys, arsenic bronze, antimonial bronze and copper–nickel–arsenic ternary alloy, are particularly emphasized and discussed. The archaeological context of Hanzhong bronzes and their significance for the archaeometallurgy research of the Shang period are discussed as well.     

Pyrite–sulfosalt reactions and semimetal fractionation in the Chinkuashih,Taiwan, copper–gold deposit: a 1 Ma paleo‐fumarole

The mineralized fracture system that underlay paleo‐fumarole field at Chinkuashih, Taiwan has been exposed by copper–gold mining to depths of about 550 m below the paleo‐surface. Its mineralogy and systematic variations in metal and semimetal (Fe, Cu, As, Sb, Bi, Hg, Cd, Sn, Zn, Pb, Se, Te, Au, Ag) concentrations provide insights into the chemical responses of a magmatic‐vapor phase as it expands through fracture arrays to the surface and discharges as fumaroles associated with more extensive solfatara. At Chinkuashih, following initial sealing of the fractures by silica‐alunite alteration, brittle failure reestablished discharge from an underlying reservoir of magmatic vapor. Crystalline pyrite was deposited first in the fractures and was succeeded and replaced by ‘enargite’ (Cu₃(As,Sb)S₄) as sulfosalt encrustations (‘sublimate’) on fracture surfaces and in extensional cracks. Subsequent recrystallization resulted in complex exsolution intergrowths with antimony fractionation to the evolving crystal–vapor interface. Heavy metal fractionation between sulfosalt and vapor enriched the vapor phase in heavy metals that subsequently precipitated as complex Bi–Hg–Sn sulfosalts in discrete areas (paleo‐fumaroles) close to the paleo‐surface in a manner analogous to modern‐day fumaroles on active volcanoes such as Vulcano, Italy. As in similar paleo‐fumaroles (e.g., El Indio, Chile and Lepanto, Philippines), the most characteristic reaction sequence is the partial replacement of the early pyrite by enargite and Fe‐tennantite. It is proposed that this reaction tracks the decrease in the pressure of the underlying magmatic‐vapor reservoir because of the sustained discharge of vapor to the surface.     

Lead isotope and chemical signature of copper from Oman and its occurrence in Mesopotamia and sites on the Arabian Gulf coast

Lead isotope data, together with an evaluation of previously published results for the chemical composition of Omani ores and copper‐base artefacts are used to define a material signature of Omani copper. Absent from our group of Bronze Age metal (Umm an Nar and Wadi Suq periods) are the signature of ores from Masirah Island and also from the vast deposits in north Oman inland from Suhar. Contemporaneous copper from Bahrain and from Tell Abraq on the Gulf coast is consistent in its material signature with Omani copper; a derivation from Omani ores of this copper is highly likely. A few exceptions at Tell Abraq point to Faynan/Timna in the southern Levant as a possible source region. Among Mesopotamian artefacts the signature of Omani copper is encountered during all cultural periods from Uruk at the end of the fourth millennium BC to Akkadian 1000 years later. Oman/Magan appears to have been particularly important during Early Dynastic III and Akkadian when about half of the copper in circulation bears the Omani signature.     

Sulfosalt melts and heavy metal (As‐Sb‐Bi‐Sn‐Pb‐Tl) fractionation during volcanic gas expansion: the El Indio (Chile) paleo‐fumarole

High‐sulfidation vein gold deposits such as El Indio, Chile, formed in fracture arrays <1000 m beneath paleo‐solfatara in volcanic terranes. Stable isotope data have confirmed a predominance of magmatic vapor during the deposition of arsenic‐rich sulfide–sulfosalt assemblages in this deposit. These provide a unique opportunity to analyze the processes and products of high‐temperature volcanic gas expansion in fractures that form the otherwise inaccessible infrastructure deep inside equivalent present‐day fumaroles. We provide field emission scanning electron microscope and LA‐ICP‐MS micro‐analytical data for the wide range of heavy, semi‐metals and metalloids (arsenic, antimony, bismuth, tin, silver, gold, tellurium and selenium) in the complex pyrite‐enargite‐Fe‐tennantite assemblages from Copper Stage mineralization in the El Indio deposit. These data document the progressive fractionation of antimony and other heavy metals, such as bismuth, during crystallization from a sulfosalt melt that condensed from expanding vapor at about 15 MPa (150 bars) and >650°C following higher temperature vapor deposition of crystalline pyrite and enargite. The sulfosalt melt aggressively corroded the earlier enargite and pyrite and hosts clusters of distinctive euhedral quartz crystals. The crystallizing sulfosalt melt also trapped an abundance of vugs within which heavy metal sulfide and sulfosalt crystals grew together with K‐Al silicates and fluorapatite. These data and their geologic context suggest that, in high‐temperature fumaroles on modern active volcanoes, over 90% of the arsenic content of the primary magmatic vapor (perhaps 2000 mg kg^?1) was precipitated subsurface as sulfosalt. Subsurface fractionation may also account for the range of exotic Pb‐Sn‐Bi‐Se sulfosalts observed in fumarole sublimates on active volcanoes such as Vulcano, Italy, as well as on extra‐terrestrial volcanoes such as Maxwell Montes, Venus.     

Fluid lives: subjectivities,gender and water in rural Bangladesh

This article seeks to contribute to the emerging debates in gender–water and gender–nature literatures by looking at the ways that gendered subjectivities are simultaneously (re)produced by societal, spatial and natural/ecological factors, as well as materialities of the body and of heterogeneous waterscapes. Drawing from fieldwork conducted in Bangladesh on arsenic contamination of drinking water, the article looks at the ways that gender relations are influenced by not just direct resource use/control/access and the implications of different types of waters, but also by the ideological constructs of masculinity/femininity, which can work in iterative ways to influence how people relate to different kinds of water. Conflicts and struggles over water inflect gendered identities and sense of self, where both men and women participate in reproducing and challenging prevailing norms and practices. As a result, multiple social and ecological factors interact in complex and interlinked ways to complicate gender–water relations, whereby socio-spatial subjectivities are re/produced in water management and end up reinforcing existing inequities. The article demonstrates that gender–water relations are not just intersected by social axes, as generally argued by feminist scholars, but also by ecological change and spatial relations vis-à-vis water, where simultaneously socialized, ecologized, spatialized and embodied subjectivities are produced and negotiated in everyday practices.