Unresolved Complexity in Assessments of Mineral Resource Depletion and Availability

Considerations of mineral resource availability and depletion form part of a diverse array of sustainable development-oriented studies, across domains such as resource criticality, life cycle assessment and material flow analysis. Given the multidisciplinary nature of these studies, it is important that a common understanding of the complexity and nuances of mineral supply chains be developed. In this paper, we provide a brief overview of these assessment approaches and expand on several areas that are conceptually difficult to account for in these studies. These include the dynamic nature of relationships between reserves, resources, cut-off grades and ore grades; the ability to account for local economic, social and environmental factors when performing global assessments; and the role that technology improvements play in increasing the availability of economically extractable mineral resources. Advancing knowledge in these areas may further enhance the sophistication and interpretation of studies that assess mineral resource depletion or availability.     

Statistical analysis of short-term water stress conditions at Riggs Creek OzFlux tower site

Theoretical and Applied Climatology - A large range of indices and proxies are available to describe the water stress conditions of an area subject to different applications, which have varying...     

Urban agriculture and the sustainability fix in Vancouver and Detroit

Both Vancouver, British Columbia, and Detroit, Michigan, have significant and growing urban agriculture movements. In this article, I follow recent work investigating the connection between urban agriculture and neoliberalization to determine how these local governments have used urban agriculture in narratives of economic development to selectively pursue a sustainability fix. I analyze how different regimes of local governance have influenced the urban agriculture movements, leading to local, hybridized fixes that adapt to different material and discursive contexts in each place. I argue that in both cities, urban agriculture has radical potential as a grassroots response to economic and environmental injustice, but has also been enrolled as a device by the local state in which the primary goal of sustainability planning becomes enhanced economic competitiveness. Pursuing an agenda of food justice requires examining the larger context and effects of municipal involvement with food movements.     

Simultaneous optical polarimetry and X-ray observations of the magnetic CV CP Tuc (AX J2315−592)

CP Tuc (AX J2315–592) shows a dip in X-rays which lasts for approximately half the binary orbit and is deeper in soft X-rays compared with hard X-rays. It has been proposed that this dip is due to the accretion stream obscuring the accretion region from view. If CP Tuc were a polar, as has been suggested, then the length of such a dip would make it unique amongst polars since in those polars in which a dip is seen in hard X-rays the dip lasts for only 0.1 of the orbit. We present optical polarimetry and RXTE observations of CP Tuc which show circular polarization levels of ∼10 per cent and find evidence for only one photometric period. These data confirm CP Tuc as a polar. Our modelling of the polarization data implies that the X-ray dip is due to the bulk of the primary accretion region being self-eclipsed by the white dwarf. The energy dependence of the dip is due to a combination of this self-eclipse and also the presence of an X-ray temperature gradient over the primary accretion region.     

Rights, the environment and Part V of the Criminal Justice and Public Order Act 1994

Summary Using figures derived from the UK Home Office, this paper analyses and reviews the impact and deployment of Part V of the Criminal Justice and Public Order Act 1994 since its enactment. This is done with special reference to its impact on citizenship and the regulation of 'the environment' and associated rural spaces. It is argued that, notwithstanding the actual use of the public order clauses in Part V of the Act, its underlying meanings are largely of a symbolic nature. Such symbolism is, however, a powerful indication of the defence of particularist constructions of rural space. It can also open out new conditions of possibility, providing a useful 'oppressed' status and media spectacle for a range of protesters and activists.     

Was the M<Subscript>w</Subscript> 7.5 1952 Kern County,California, earthquake induced (or triggered)?

Several recent studies have presented evidence that significant induced earthquakes occurred in a number of oil-producing regions during the early and mid-twentieth century related to either production or wastewater injection. We consider whether the 21 July 1952 M_w 7.5 Kern County earthquake might have been induced by production in the Wheeler Ridge oil field. The mainshock, which was not preceded by any significant foreshocks, occurred 98 days after the initial production of oil in Eocene strata at depths reaching 3 km, within ~1 km of the White Wolf fault (WWF). Based on this spatial and temporal proximity, we explore a potential causal relationship between the earthquake and oil production. While production would have normally be expected to have reduced pore pressure, inhibiting failure on the WWF, we present an analytical model based on industry stratigraphic data and best estimates of parameters whereby an impermeable splay fault adjacent to the main WWF could plausibly have blocked direct pore pressure effects, allowing the poroelastic stress change associated with production to destabilize the WWF, promoting initial failure. This proof-of-concept model can also account for the 98-day delay between the onset of production and the earthquake. While the earthquake clearly released stored tectonic stress, any initial perturbation on or near a major fault system can trigger a larger rupture. Our proposed mechanism provides an explanation for why significant earthquakes are not commonly induced by production in proximity to major faults.     

Stable isotope paleohydrology and chemostratigraphy of the Albian Wayan Formation from the wedge-top depozone,North American Western Interior Basin

Understanding of the role of atmospheric moisture and heat transport in the climate system of the Cretaceous greenhouse world represents a major challenge in Earth system science.Stable isotopic paleohydrologic data from mid-Cretaceous paleosols in North America,from paleoequatorial to paleoArctic latitudes,have been used to constrain the oxygen isotope mass balance of the Albian hydrologic cycle.Over the range from 40°-50°N paleolatitude,sideritic paleosols predominate,indicating paleoenvironments with positive precipitation-evaporation(P-E)balances.Local exceptions occur on leeward side of the Sevier Orogen,where calcic paleosols in the wedge-top depozone record paleoenvironments with negative P-E balances in the orographic rain shadow.Stratigraphic sections in the Wayan Formation of Idaho(WF)were sampled from the wedge-top depozone.The units consist of stacked m-scale mudstone paleosols separated by m-scale sandstone-siltstone beds.Sections were sampled for organic carbon isotope profiles,and B-horizons from 6 well-developed paleosols were sampled for detrital zircons to determine maximum depositional ages.The first of these from the WF has produced a U-Pb concordia age of 101.0±1.1 Ma.This same WF section has produced a stratigraphic trend of upwardly decreasingδ~(13)C values ranging from-24‰upwards to-27‰VPDB,suggesting correlation to the late Albian C15 C-isotope segment.Pedogenic carbonates from the WF principally consist of micritic calcite,with carbon-oxygen isotope values that array along meteoric calcite lines(MCLs)withδ~(18)O values that range from-9.47‰up to-8.39‰VPDB.At approximately 42°N paleolatitude,these MCL values produce calculated paleoprecipitation values of-8.12‰to-7.04‰VSMOW,a range that is consistent with the estimates produced from other proxies at the same paleolatitudes across North America.These results indicate that despite the orographic rain shadow effect,the processes of meridional atmospheric moisture transport in this locale were similar to those in more humid mid-latitude paleoenvironments elsewhere in the continent.