Abstract Emerald from the Binntal occurrence in the Canton of Valais in Switzerland has been studied to determine its chemical zonation, stable isotopic signatures, depositional-fluid characteristics, pressure-temperature emplacement conditions, and formational model. The emerald is vanadium-rich, with optical and blue cathodoluminescence zoning related to chemical variations, primarily in V 2 O 3 concentrations. The hydrogen isotope signature of the emerald channel fluids is unique and in agreement with previously identified high-altitude (deuterium-depleted) Alpine-age meteoric fluids. Field studies, fluid inclusion analyses, and oxygen isotope thermometry are consistent with a metamorphic formational model for the Binntal emerald at temperatures and hydrostatic pressures ranging from 200 to 400 °C and 100 to 250 Mpa, respectively. This corresponds to formational depths on the order of 4 to 9 km and fluids consistent with a 10–20 Ma CO 2 -dominant fluid with approximate mole percentages of 84.0, 11.9, 1.5, 1.3, 0.3, and 0.5 for CO 2 , H 2 O, CH 4 , N 2 , H 2 S, and NaCl, respectively.
Abstract Although the UN and EU focus their climate policies on the prevention of a 2 °C global mean temperature rise, it has been estimated that a rise of at least 4 °C is more likely. Given the political climate of inaction, there is a need to instigate a bottom-up approach so as to build domestic support for future climate treaties, empower citizens, and motivate leaders to take action. A review is provided of the predominant top-down cap-and-trade policies in place – the Kyoto Protocol and EU Emissions Trading Scheme (EU ETS) – with a focus on the grandfathering of emissions entitlements and the possibility of offsetting emissions. These policies are evaluated according to two criteria of justice and it is concluded that they fail to satisfy them. Some suggestions as to how the EU ETS can be improved so as to enable robust climate action are also offered. Policy relevance The current supranational climate policy has not been successful and global leaders have postponed the adoption of a meaningful successor to the Kyoto Protocol. In view of this inaction, bottom-up approaches with regard to climate policy should be further developed. It is argued that two of the main top-down policies, grandfathering and offsetting, impede the avowed goals of EU climate policy and pose significant ethical dilemmas with regard to participatory and intergenerational justice. In order to provide a more robust EU climate policy, the EU should inter alia provide a long-term perspective for investors, reduce the volatility of the carbon price, and prepare for the possibility of carbon leakage. Keywords: bottom-up initiativesclimate policyethicsEU ETSgrandfatheringoffsettingtop-down approaches Acknowledgements The authors wish to thank the referees for their most insightful comments, Marc Davidson for his remarks, Simon Caney for providing research material and Julian Cockbain for language editing. Notes The 450 Scenario was developed by the IEA and describes the emissions reductions the energy sector must undertake if 450 ppm CO2e is the peak emissions target (OECD/IEA, Citation2010). It is worth remembering that energy emissions represent around two-thirds of global emissions, while agriculture accounts for between 30% and 35%. Agriculture consists mostly of land use, land-use change and forestry (LULUCF), and the production of meat and dairy products. See FAO (Citation2006), Foley et al. (Citation2011), and Stern (Citation2010). It should be noted, however, that the recent proposal by the European Commission to move to a 25% reduction target was met with fierce internal opposition (King, Citation2012). Some commentators have opted for an intermediate approach that recognizes both the dominant role of a centralized international authoritative body and the need to address different elements of climate governance in an incremental fashion and embed them in an international political framework (see e.g. Falkner, 2012; Falkner, Stephan, & Vogler, Citation2010). Others have advocated stringent state-governed climate policy regulation complemented by market-based mechanisms (Adelman & Engel, Citation2008; Andreen, Glicksman, Menselson, Steinzor, & Jones, Citation2008; Kaswan, Citation2011). An additional and important criterion of justice is whether the climate policy compensates climate victims. This, however, falls outside of the scope of this article.
Emerald from the deposits at Poona shows micrometre-scale chemical, optical, and cathodoluminescence zonation. This zonation, combined with fluid inclusion and isotope studies, indicates early emerald precipitation from a single-phase saline fluid of approximately 12 weight percent NaCl equivalent, over the temperature range of 335–525 °C and pressures ranging from 70 to 400 MPa. The large range in pressure and temperature likely reflects some post entrapment changes and re-equilibration of oxygen isotopes. Secondary emerald-hosted fluid inclusions indicate subsequent emerald precipitation from higher salinity fluids. Likewise, the δ18O-δD of channel fluids extracted from Poona emerald is consistent with multiple origins yielding both igneous and metamorphic signatures. The combined multiple generations of emerald precipitation, different fluid compositions, and the presence of both metamorphic and igneous fluids trapped in emerald, likely indicate a protracted history of emerald precipitation at Poona conforming to both an igneous and a metamorphic origin at various times during regional lower amphibolite to greenschist facies metamorphism over the period ~2710–2660 Ma.
Abstract Central aims of IODP Expedition 352 were to delineate and characterize the magmatic stratigraphy in the Bonin forearc to define key magmatic processes associated with subduction initiation and their potential links to ophiolites. Expedition 352 penetrated 1.2 km of magmatic basement at four sites and recovered three principal lithologies: tholeiitic forearc basalt (FAB), high-Mg andesite, and boninite, with subordinate andesite. Boninites are subdivided into basaltic, low-Si, and high-Si varieties. The purpose of this study is to determine conditions of crystal growth and differentiation for Expedition 352 lavas and compare and contrast these conditions with those recorded in lavas from mid-ocean ridges, forearcs, and ophiolites. Cr# (cationic Cr/Cr+Al) vs. TiO2 relations in spinel and clinopyroxene demonstrate a trend of source depletion with time for the Expedition 352 forearc basalt to boninite sequence that is similar to sequences in the Oman and other suprasubduction zone ophiolites. Clinopyroxene thermobarometry results indicate that FAB crystallized at temperatures (1142–1190 °C) within the range of MORB (1133–1240 °C). When taking into consideration liquid lines of descent of boninite, orthopyroxene barometry and olivine thermometry of Expedition 352 boninites demonstrate that they crystallized at temperatures marginally lower than those of FAB, between ~1119 and ~1202 °C and at relatively lower pressure (~0.2–0.4 vs. 0.5–4.6 kbar for FAB). Elevated temperatures of boninite orthopyroxene (~1214 °C for low-Si boninite and 1231–1264 °C for high-Si boninite) may suggest latent heat produced by the rapid crystallization of orthopyroxene. The lower pressure of crystallization of the boninite may be explained by their lower density and hence higher ascent rate, and shorter distance of travel from place of magma formation to site of crystallization, which allowed the more buoyant and faster ascending boninites to rise to shallower levels before crystallizing, thus preserving their high temperatures.
