Exploring the associations between cooling centre accessibility and marginalization in Montreal,Toronto, and Vancouver,Canada

Cooling centres provide respite, safety, and social support during extreme heat events for populations that do not have the resources to own or operate in-home air conditioning. The objective of this study was to measure the spatial accessibility of cooling centres and analyze the associations between cooling centre access and marginalization in Montreal, Toronto, and Vancouver, Canada. The potential spatial accessibility of cooling centres within a 15-minute walk was measured at the dissemination area scale using the two-step floating catchment area method. A two-stage modelling approach was used to analyze the associations between cooling centre access and marginalization. Approximately 62%, 58%, and 54% of the populations in Montreal, Toronto, and Vancouver had access to at least one cooling centre. In Montreal and Vancouver, high marginalization areas were more likely to have cooling centre access than low marginalization areas. Of the areas with cooling centre access, smaller access scores were observed in areas with high residential instability. Approximately one-fifth of the areas in each city had no cooling centre access and high marginalization, and may be considered for future cooling centres or programs that improve accessibility to existing centres.     

Surface controls on the characteristics of natural CO2 seeps: implications for engineered CO2 stores

CO₂ injected into rock formations for deep geological storage must not leak to surface, since this would be economically and environmentally unfavourable, and could present a human health hazard. In Italy natural CO₂ degassing to the surface via seeps is widespread, providing an insight into the various styles of subsurface ‘plumbing’ as well as surface expression of CO₂ fluids. Here we investigate surface controls on the distribution of CO₂ seep characteristics (type, flux and temperature) using a large geographical and historical data set. When the locations of documented seeps are compared to a synthetic statistically random data set, we find that the nature of the CO₂ seeps is most strongly governed by the flow properties of the outcropping rocks, and local topography. Where low‐permeability rocks outcrop, numerous dry seeps occur and have a range of fluxes. Aqueous fluid flow will be limited in these low‐permeability rocks, and so relative permeability effects may enable preferential CO₂ flow. CO₂ vents typically occur along faults in rocks that are located above the water table or are low permeability. Diffuse seeps develop where CO₂ (laterally supplied by these faults) emerges from the vadose zone and where CO₂ degassing from groundwater follows a different flow path due to flow differences for water and CO₂ gas. Bubbling water seeps (characterized by water bubbling with CO₂) arise where CO₂ supply enters the phreatic zone or an aquifer. CO₂‐rich springs often emerge where valleys erode into CO₂ aquifers, and these are typically high flux seeps. Seep type is known to influence human health risk at CO₂ seeps in Italy, as well as the topography surrounding the seep which affects the rate of gas dispersion by wind. Identifying the physical controls on potential seep locations and seep type above engineered CO₂ storage operations is therefore crucial to targeted site monitoring strategy and risk assessment. The surface geology and topography above a CO₂ store must therefore be characterized in order to design the most effective monitoring strategy.     

Ceramic Production and Interaction in the Northern Range of Trinidad

Regional syntheses based on data recovered mostly from outside of the Northern Range have characterized the mountainous region in northern Trinidad as a boundary between two distinct interaction spheres during the Early Ceramic Age (ca. AD 350–650/800) (Boomert 2000 Boomert, A. 2000. Trinidad, Tobago and the Lower Orinoco interaction Sphere: An Archaeological/Ethnohistorical Study. Alkmaar: Cairi Publications. [Google Scholar]). Changes occurring on Trinidad, other islands of the southern Lesser Antilles, and the South American mainland resulted in the disintegration of these earlier style zones during the final centuries of the Early Ceramic (Boomert 2000 Boomert, A. 2000. Trinidad, Tobago and the Lower Orinoco interaction Sphere: An Archaeological/Ethnohistorical Study. Alkmaar: Cairi Publications. [Google Scholar], 2010). This period of Late Ceramic cultural realignment was characterized by climate change, the renegotiation of political and social networks, and demographic transformations. We consider newly recovered ceramic evidence from the central Northern Range in order to evaluate the characterization of the region as a boundary and the region's role in broader Caribbean trends. We examine participation in interaction spheres to provide a more nuanced understanding of regional dynamics as they were expressed locally. Ceramic data indicate that occupants of the central Northern Range interpreted regional styles using locally derived materials, thus simultaneously engaging regional traditions and constructing local patterns of resource exploitation.     

Polyphasic hydrothermal and meteoric fluid regimes during the growth of a segmented fault involving crystalline and carbonate rocks (Barcelona Plain,NE Spain)

A polyphasic tectonic‐fluid system of a fault that involves crystalline and carbonate rocks (Hospital fault, Barcelona Plain) has been inferred from regional to thin section scale observations combined with geochemical analyses. Cathodoluminescence, microprobe analyses and stable isotopy in fracture‐related cements record the circulation of successive alternations of hydrothermal and low‐temperature meteoric fluids linked with three main regional tectonic events. The first event corresponds to the Mesozoic extension, which had two rifting stages, and it is characterized by the independent tectonic activity of two fault segments, namely southern and northern Hospital fault segments. During the Late Permian‐Middle Jurassic rifting, these segments controlled the thickness and distribution of the Triassic sediments. Also, dolomitization was produced in an early stage by Triassic seawater at shallow conditions. During increasing burial, formation of fractures and their dolomite‐related cements took place. Fault activity during the Middle Jurassic–Late Cretaceous rifting was localized in the southern segment, and it was characterized by hydrothermal brines, with temperatures over 180°C, which ascended through this fault segment precipitating quartz, chlorite, and calcite. The second event corresponds to the Paleogene compression (Chattian), which produced exhumation, folding and erosion, favouring the percolation of low‐temperature meteoric fluids which produced the calcitization of the dolostones and of the dolomite cements. The third event is linked with the Neogene extension, where three stages have been identified. During the syn‐rift stage, the southern segment of the Hospital fault grew by tip propagation. In the relay zone, hydrothermal brines with temperature around 140°C upflowed. During the late postrift, the Hospital fault acted as a unique segment and deformation occurred at shallow conditions and under a low‐temperature meteoric regime. Finally, and possibly during the Messinian compression, NW‐SE strike‐slip faults offset the Hospital fault to its current configuration.     

Carbon dioxide controlled earthquake distribution pattern in the NW Bohemian swarm earthquake region,western Eger Rift,Czech Republic – gas migration in the crystalline basement

The ascent of magmatic carbon dioxide in the western Eger (Oh?e) Rift is interlinked with the fault systems of the Variscian basement. In the Cheb Basin, the minimum CO₂ flux is about 160 m³ h^?1, with a diminishing trend towards the north and ceasing in the main epicentral area of the Northwest Bohemian swarm earthquakes. The ascending CO₂ forms Ca‐Mg‐HCO₃ type waters by leaching of cations from the fault planes and creates clay minerals, such as kaolinite, as alteration products on affected fault planes. These mineral reactions result in fault weakness and in hydraulically interconnected fault network. This leads to a decrease in the friction coefficient of the Coulomb failure stress (CFS) and to fault creep as stress build‐up cannot occur in the weak segments. At the transition zone in the north of the Cheb Basin, between areas of weak, fluid conductive faults and areas of locked faults with frictional strength, fluid pressure can increase resulting in stress build‐up. This can trigger strike‐slip swarm earthquakes. Fault creep or movements in weak segments may support a stress build‐up in the transition area by transmitting fluid pressure pulses. Additionally to fluid‐driven triggering models, it is important to consider that fluids ascending along faults are CO₂‐supersaturated thus intensifying the effect of fluid flow. The enforced flow of CO₂‐supersaturated fluids in the transitional zone from high to low permeability segments through narrowings triggers gas exsolution and may generate pressure fluctuations. Phase separation starts according to the phase behaviour of CO₂‐H₂O systems in the seismically active depths of NW Bohemia and may explain the vertical distribution of the seismicity. Changes in the size of the fluid transport channels in the fault systems caused, or superimposed, by fault movements, can produce fluid pressure increases or pulses, which are the precondition for triggering fluid‐induced swarm earthquakes.     

南宋川陕战区兵力部署的失衡与吴曦之变

南宋在川陕战区兵力部署中,基于战略防御和节制武将的考虑,形成兴州、金州、兴元府三大屯驻重心。在具体兵力分布上,由于吴氏武将集团的影响,兴州驻军的数量与实力最为强大,呈现出严重的失衡状态。兴州驻军力量过于强大是吴曦据兴州叛变的关键因素。吴曦叛变平定后,南宋对兴州军事力量予以分化,又导致兵力分散和不利于边疆防御的弊端,体现出南宋削弱地方军事力量与加强边疆防御的两难困境。川陕战区兵力部署的演变,蕴涵着南宋加强中央集权的真实内容。     

Digging Deep for Justice: A Radical Re-imagination of the Artisanal Gold Mining Sector in Ghana

Abstract:  This article explores the concept of "contact zones" to counteract misrecognition and exclusion in the artisanal gold mining sector of Ghana. The large majority of the 300,000–500,000 Ghanaian artisanal miners work without an official license, illegally. Due to their encroachment on corporate concession lands, the use of toxic mercury in the gold extraction process, and the social disruption caused by their migratory activities, these miners are often marginalized and criminalized. Yet, devaluation and misrecognition hamper environmental stewardship and participation in political decision-making. Through parity-fostering participatory research, I propose a radical re-imagination of the sector that encourages agency and flourishing among these ostracized men and women diggers.     

Inferring attitudes from behavior

Abstract

The Middle East has long been a conflict zone; the Palestinian-Israeli conflict has been a persistent factor for decades, and there have been wars over natural resources, ideological causes, and national or religious cleavages as well. How does a historian begin to compile a documentary record of such a struggle? At the beginning of my research stay in the Middle East in 2007, I decided to keep a diary about my experiences and assessments in the field. In this article, I recount and reflect about those experiences in order to propose potential solutions to the problem of on-site research in unstable areas. While field research generally requires a particular kind of preparation, and always faces obstacles and challenges, the success of fieldwork under difficult and hostile research settings is dependent on the skills of the researcher, and his or her ability and preparedness for the problems the nature of the research inevitably will bring forward.     

Changes in chemical composition caused by water–rock interactions across a strike‐slip fault zone: case study of the Atera Fault,Central Japan

In some cases, water–rock interactions in fault zones can affect radionuclide migration. Here, we analyzed the chemical compositions of well‐exposed fault rocks from the strike‐slip Atera Fault, Central Japan, in order to understand the variability and behavior of major and selected trace elements. The fault zone has a 1.2‐m‐wide, smectite‐rich fault core and paired damage zones that developed within welded tuff on one side of the core and within granite on the other side. The 30‐cm‐wide, kaolinite‐rich fault gouge is developed in granite cataclasite, and it shows indications of the latest fault activity, while the 1.2‐m‐wide fault core appears to be older. Hydrogen and oxygen isotope ratios in the clay‐rich fault gouges, and carbon and oxygen isotope ratios in carbonates indicate that the two major clay‐rich zones formed in bedrock near the surface, consistent with observed deformation structures. Based on chemical analyses, we identified (1) a slight depletion in SiO₂, Na₂O, K₂O, and light rare earth elements at the edges of the 1.2‐m‐wide fault core, (2) a clear depletion in SiO₂, Na₂O, K₂O, and all rare earth elements except Eu in the 30‐cm‐wide fault gouge, and (3) an increase in CaO, MnO, and heavy rare earth elements across the entire 1.2‐m‐wide fault core. Findings (1) and (2) reflect water–rock interactions in the 1.2‐m‐wide fault core and in the 30‐cm‐wide fault gouge that resulted in the formation of smectite and kaolinite. Finding (3) reflects carbonate precipitation caused by the addition of basalt fragments from a nearby site to the 1.2‐m‐wide fault core during faulting, and subsequent sorption reactions of heavy rare earth elements via processes such as complexation with the carbonates.