Monitoring fluid chemistry in iron oxide–copper–gold‐related metasomatic processes,eastern Mt Isa Block,Australia

Most researchers in the Proterozoic eastern Mt Isa Block, NW Queensland, Australia, favour magmatic fluid and salt sources for sodic‐(calcic) alteration and iron oxide–copper–gold mineralization. Here we compare spatial, mineralogic and stable isotope data from regional alteration assemblages with magmatic and magmatic‐hydrothermal interface rocks in order to track chemical and isotopic variations in fluid composition away from inferred fluid sources. Tightly clustered δ¹⁸O values for magnetite, quartz, feldspar and actinolite for igneous‐hosted samples reflect high temperature equilibration in the magmatic‐hydrothermal environment. In contrast, these minerals record predominantly higher δ¹⁸O values in regional alteration and Cu–Au mineralization. This dichotomy reflects partial equilibration with isotopically heavier wallrocks and slightly lower temperatures. Increases in Si concentrations of metasomatic amphiboles relative to igneous amphiboles in part reflect cooling of metasomatic fluids away from igneous rocks. Variations in X_Mg for metasomatic amphiboles indicate local wallrock controls on amphibole chemistry, while variations in X_Cl/X_OH ratios for amphiboles (at constant X_Mg) indicate variable aH₂O/aHCl ratios for metasomatic fluids. Biotite geochemistry also reflects cooling and both increases and decreases in aH₂O/aHCl for fluids away from plutonic rocks. Decreased aH₂O/aHCl ratios for metasomatic fluids reflect in part scavenging of chlorine out of meta‐evaporite sequences, although this process requires already saline fluids. Local increases in aH₂O/aHCl ratios, as well as local decreases in δ¹⁸O values for some minerals (most notably haematite and epithermal‐textured quartz), may indicate ingress of low salinity, low δ¹⁸O fluids of possible meteoric origin late in the hydrothermal history of the region. Taken together, our observations are most consistent with predominantly magmatic sources for metasomatic fluids in the eastern Mt Isa Block, but record chemical and isotopic variations along fluid flow paths that may be important in explaining some of the diversity in alteration and mineralization styles in the district.     

Sustainability Science Partnerships in Concept and in Practice: a Guide to a New Curriculum from a European Perspective

This paper makes the case for advancing sustainability science partnerships (SSPs) both within universities and through innovative means of integrating universities with external public‐private and civil sectors. It links the basic principles of sustainable development with an emerging science of cooperative learning that connects researchers to a wide range of partners. SSPs are specifically designed to be transformational through becoming active agents for societal change. Universities play a special role here because they can act both as communication networks and as laboratories for developing the capability to design and manage SSPs in the creative transition to sustainability. It is gratifying to note that these ideas are beginning to emerge in a number of universities, with European examples being highlighted in this paper. Further steps towards introducing full‐blooded SSPs across the university spectrum are suggested.     

The question of national identity and the institutionalisation of the visual arts in Grenada

ABSTRACT. This article argues for a close relationship between national identity and the institutionalisation of the visual arts in Grenada. Art, which is intrinsic to all humans, predates its institutionalisation: it is only institutionalised in societies with a strong sense of national identity. In order to explain the role of national identity in the formation of national art, the article begins by examining the period following World War II, when Grenada – still under British colonialism – was undergoing intense social and political changes. To understand these changes, the analysis of the stratification system is paramount. The article delineates three groups on the basis of the value systems developed historically: the elite, the masses and a small, growing middle class situated between these two groups. The works of three prominent Grenadian artists illustrate the argument that institutionalisation of art requires a strong sense of national identity, and through this process the artistic development of a society occurs. Furthermore, understanding this process requires a focus on the ways in which social and political groups or classes impeded the development of a national identity, preventing the institutionalisation of the arts.     

Society and politics in China today

China's social and economic transformations, and their growing global impact, have prompted a plethora of books. This review article examines five recent books in Polity's China today series as a basis for discussion about society and politics in China. The series is structured around applying different themes or concepts to China, and these five look at consumption, social welfare, class, ethnicity, and the nature, role and performance of the Communist Party and state. The books provide well‐researched and balanced accounts of developments in China, especially since the era of ‘reform and opening up’ began in 1978. The article argues that important themes of the books—the growing discourse of consumption, the depoliticization of class as socio‐economic strata, the Party‐state as a pragmatic provider of citizen services, and the role of the private sector in the provision of social welfare—are all features of the current phase of a globalized capitalist modernity, and concludes that while the country wants to be seen as different, the accounts of politics and society in this series suggests that China today offers more of an alternative within that modernity than an alternative to it.     

Granite‐related overpressure and volatile release in the mid crust: fluidized breccias from the Cloncurry District,Australia

The source and transport regions of fluidized (transported) breccias outcrop in the Cloncurry Fe‐oxide–Cu–Au district. Discordant dykes and pipes with rounded clasts of metasedimentary calc–silicate rocks and minor felsic and mafic intrusions extend several kilometres upwards and outwards from the contact aureole of the 1530 Ma Williams Batholith into overlying schists and amphibolites. We used analytical equations for particle transport to estimate clast velocities (≥20 m sec^?1), approaching volcanic ejecta rates. An abrupt release of overpressured magmatic‐hydrothermal fluid is suggested by the localization of the base of the breccias in intensely veined contact aureoles (at around 10 km, constrained by mineral equilibria), incorporation of juvenile magmatic clasts, the scale and discordancy of the bodies, and the wide range of pressure variation (up to 150 MPa) inferred from CO₂ fluid inclusion densities and related decrepitation textures. The abundance of clasts derived from depth, rather than from the adjacent wallrocks, suggests that the pressure in the pipes was sufficient to restrict the inwards spalling of fragments from breccia walls; that is, the breccias were explosive rather than implosive, and some may have vented to the surface. At these depths, such extreme behaviour may have been achieved by release of dissolved fluids from crystallizing magma, in combination with a strongly fractured and fluid‐laden carapace, sitting under a strong, low permeability barrier. The relationship of these breccias to the Ernest Henry iron‐oxide–Cu–Au deposit suggests they may have been sources of fluids or mechanical energy for ore genesis, or alternately provided permeable pathways for later ore fluids.