The Nature of Decision Making in the Practice of Dwelling: A Practice Theoretical Approach to Understanding Maintenance and Retrofitting of Homes in the Context of Climate Change     

Håkon Fyhn  Nina Baron 《社会与自然资源》2017,30(5):555-568

In order to make existing private housing more energy efficient, various policies aim at influencing decisions made by homeowners regarding renovation and retrofitting in Scandinavia. Presenting two case studies from Denmark and Norway, we take one step back and observe the whole process of keeping a home habitable. Inspired by theories of Tim Ingold and Elizabeth Shove, we suggest calling this process “the practice of dwelling.” Rather than focusing on decisions and acts pertaining to retrofitting alone, we observe how maintenance and retrofitting are parts of an ongoing practice of dwelling. The cases demonstrate how decisions can be understood as embedded in the practice of dwelling, and how a readiness for decisions regarding retrofitting is created, or not, in this practice. We suggest shifting focus from the outcome of decisions, to attention toward the process that leads to readiness for making the decision in the first place.  相似文献   

Seismic wave velocities in the lower mantle     

Markus Båth 《Pure and Applied Geophysics》1966,65(1):5-11

Summary The vertical velocity variations of longitudinal and transverse waves in the earth's interior in the depth range of 413 to 2800 km are put into mathematical form. Expressions of the velocities in terms of power functions of the radius are found to conform closely to the given velocities, as well as to be very simple in applications. Examples of the use of such formulas are given, including calculations of travel times and of radial velocity gradients.  相似文献   

Widespread dispersal of Icelandic tephra: how does the Eyjafjöll eruption of 2010 compare to past Icelandic events?     

Siwan M. Davies  Gudrun Larsen  Stefan Wastegård  Chris S. M. Turney  Valerie A. Hall  Lisa Coyle  Thor Thordarson 《第四纪科学杂志》2010,25(5):605-611

The Eyjafjöll AD 2010 eruption is an extraordinary event in that it led to widespread and unprecedented disruption to air travel over Europe – a region generally considered to be free from the hazards associated with volcanic eruptions. Following the onset of the eruption, satellite imagery demonstrated the rapid transportation of ash by westerly winds over mainland Europe, eventually expanding to large swathes of the North Atlantic Ocean and the eastern seaboard of Canada. This small‐to‐intermediate size eruption and the dispersal pattern observed are not particularly unusual for Icelandic eruptions within a longer‐term perspective. Indeed, the Eyjafjöll eruption is a relatively modest eruption in comparison to some of the 20 most voluminous eruptions that have deposited cryptotephra in sedimentary archives in mainland Europe, such as the mid Younger Dryas Vedde Ash and the mid Holocene Hekla 4 tephra. The 2010 eruption, however, highlights the critical role that weather patterns play in the distribution of a relatively small amount of ash and also highlights the spatially complex dispersal trajectories of tephra in the atmosphere. Whether or not the preservation of the Eyjafjöll 2010 tephra in European proxy archives will correspond to the extensive distributions mapped in the atmosphere remains to be seen. The Eyjafjöll 2010 event highlights our increased vulnerability to natural hazards rather than the unparalleled explosivity of the event. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Middle and Late Weichselian (Devensian) glaciation history of south-western Norway,North Sea and eastern UK     

H.P. Sejrup  A. Nygård  A.M. Hall  H. Haflidason 《Quaternary Science Reviews》2009,28(3-4):370-380

Data from eastern England, Scotland, the northern North Sea and western Norway have been compiled in order to outline our current knowledge of the Middle and Late Weichselian glacial history of this region. Radiometric dates and their geological context from key sites in the region are presented and discussed. Based on the available information the following conclusions can be made: (i) Prior to 39 cal ka and most likely after ca 50 cal ka Scotland and southern Norway were extensively glaciated. Most likely the central North Sea was not glaciated at this time and grounded ice did not reach the shelf edge. (ii) During the time interval between 29 and 39 ka periods with ameliorated climate (including the Ålesund, Sandnes and Tolsta Interstadials) alternated with periods of restricted glaciation in Scotland and western Norway. (iii) Between 29 and 25 ka maximum Weichselian glaciation of the region occurred, with the Fennoscandian and British ice sheets coalescing in the central North Sea. (iv) Decoupling of the ice sheets had occurred at 25 ka, with development of a marine embayment in the northern North Sea (v) Between 22 and 19 ka glacial ice expanded westwards from Scandinavia onto the North Sea Plateau in the Tampen readvance. (vi) The last major expansion of glacial ice in the offshore areas was between 17.5 and 15.5 ka. At this time ice expanded in the north-western part of the region onto the Måløy Plateau from Norway and across Caithness and Orkney and to east of Shetland from the Moray Firth. The Norwegian Channel Ice Stream (NCIS), which drained major parts of the south-western Fennoscandian Ice Sheet, was active at several occasions between 29 and 18 ka.  相似文献   

Massive serpentinite carbonation at Linnajavri,N–Norway     

Andreas Beinlich  Oliver Plümper  Jörn Hövelmann  Håkon Austrheim  Bjørn Jamtveit 《地学学报》2012,24(6):446-455

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Quaternary palaeoenvironments and multi-storey valley fill architecture along the Mezen and Severnaya Dvina river valleys,Arkhangelsk region,NW Russia     

Maria A. Jensen  Igor N. Demidov  Eiliv Larsen  Astrid Lyså 《Quaternary Science Reviews》2009,28(23-24):2489-2506

The modern Severnaya Dvina and Mezen river systems in the Arkhangelsk region, NW Russia, are located within extensive palaeovalley systems. The palaeovalleys form depressions in bedrock and have controlled the drainage systems in the area at least since the Last Interglacial. Vertically stacked marine to fluvial sediments reflect deposition during fluctuating climate and sea levels.A compilation of lithostratigraphical data collected during the last decade has been coupled with bedrock topography and geomorphology from satellite images in order to describe the valley fill architecture for the two valley systems. Each system has been divided into a number of depositional units (storeys) separated by incision/non-deposition and used to investigate the timing of aggradational versus incisional phases. Time constraints for each phase are provided by optically stimulated luminescence (OSL) ages, and aggradation and incision are linked to independent records of climate and sea level change.The pattern of aggradation and erosion is regional and primarily driven by episodes of increasing and decreasing sediment supply. Aggradation is correlated to times of deglaciation with high sediment supply from the ice margin, release of sediment from ice-dammed lakes and low vegetation and degradation of permafrost on the flood plain. Incision is related to cold intervals with low sediment supply, delayed incision due to isostatic uplift and drainage of ice-dammed lakes. Relative sea level change controls the distribution of marine deposits, which show significant regional variations due to variable isostatic response across the region. Sea level change plays a limited role for fluvial aggradation/incision in the study area.  相似文献   

A Lateglacial–early Holocene tephrochronology for SW Sweden     

Carl Lilja  Ewa M. Lind  Björn Morén  Stefan Wastegård 《Boreas: An International Journal of Quaternary Research》2013,42(3):544-554

Four cores from southwestern Sweden are presented together with their tephra geochemistry. Two cryptotephra horizons were confirmed geochemically in the cores, the Vedde Ash and the Hässeldalen Tephra. The Lateglacial Hässeldalen Tephra (11 360–11 300 cal. a BP) offers great potential as a regional isochrone to add a new degree of certainty to the deglaciation chronology of southern Sweden, including the extent of glacial Lake Bolmen. In addition, the geographical distribution of the Hässeldalen Tephra has recently been extended outside of Sweden, making it an important time‐marker horizon in northern Europe. There are potential difficulties, however. Proper identification of the actual isochrone is complicated by the vertical pattern of shard distribution, which could be the result of several eruptive events, as well as by the fact that shards from the 10‐ka Askja horizon (10 500–10 350 cal. a BP) were found in close stratigraphical proximity. The geochemical data presented are the result of improved EPMA methodology, which significantly reduces sodium mobilization. The results therefore have slightly altered values, which has consequences for classifying new finds when they are compared with previous data for geochemically similar tephras. Finally, potential indications of the Borrobol/Penifiler horizon are presented, although the existence of the horizon could not be confirmed geochemically. This highlights the need to retrieve cores from different locations within a basin based on an analysis of basin morphology if horizons are to be located.  相似文献   

Formation of corundum megacrysts during H<Subscript>2</Subscript>O-saturated incongruent melting of feldspar: P–T pseudosection-based modelling from the Skattøra migmatite complex,North Norwegian Caledonides     

Kåre Kullerud  Pritam Nasipuri  Erling J. K. Ravna  Rune S. Selbekk 《Contributions to Mineralogy and Petrology》2012,164(4):627-641

Corundum megacryst-bearing rocks associated with the high-pressure migmatites of the Skattøra migmatite complex (SMC) belonging to the Nakkedal Nappe Complex, North Norwegian Caledonides, display a classical example of incongruent melting of plagioclase under water-saturated conditions. Petrography and micro-textures suggest that several centimetre long corundum megacrysts formed from the silicate melt along with amphibole (pargasite) and plagioclase (X_An ~ 0.47). The corundum-bearing leucosomes are rich in biotite compared to the other mafic units of SMC. Locally, margarite occurs in coronas around corundum megacrysts. Geochemically, the corundum-bearing rocks are enriched in Al, K, Rb and Ba and depleted in Fe, Mg and Ca compared to the leucogabbroic host rock. A P–T pseudosection of the leucogabbro indicates that feldspar breakdown and corundum formation occurred at temperatures >850 °C and pressure >1.2 GPa. The calculated equilibrium P–T of the corundum-bearing rock corresponds to 750–825 °C and 0.9–1.1 GPa. The P–T pseudosection of margarite indicates that margarite formed after cooling and decompression to P–T conditions corresponding to 600 °C at 0.5 GPa. Based on geochemical and mineral chemical analysis coupled with thermodynamic modelling, we suggest that formation of corundum occurred as a result of high-pressure incongruent melting of plagioclase in the presence of a K-, Rb- and Ba-rich external fluid. It is also suggested that the external fluid transported out portions of Ca, Fe and Mg, resulting in an increase of the peraluminousity of the melt and promoting further growth of corundum.  相似文献   

Phase-equilibrium geobarometers for silicic rocks based on rhyolite-MELTS. Part 1: Principles,procedures, and evaluation of the method     

Guilherme?A.?R.?GualdaEmail author  Mark?S.?Ghiorso 《Contributions to Mineralogy and Petrology》2014,168(1):1033

Constraining the pressure of crystallization of magmas is an important but elusive task. In this work, we present a method to derive crystallization pressures for rocks that preserve glass compositions (either glass inclusions or matrix glass) representative of equilibration between melt, quartz, and 1 or 2 feldspars. The method relies on the well-known shift of the quartz–feldspar saturation surface toward higher normative quartz melt compositions with decreasing pressure. The critical realization for development of the method is the fact that melt, quartz and feldspars need to be in equilibrium at the liquidus for the melt composition. The method thus consists of calculating the saturation surfaces for quartz and feldspars using rhyolite-MELTS over a range of pressures, and searching for the pressure at which the expected assemblage (quartz+1 feldspar or quartz+2 feldspars) is found at the liquidus. We evaluate errors resulting from uncertainties in glass composition using a series of Monte Carlo simulations for a quartz-hosted glass inclusion composition from the Bishop Tuff, which reveal errors on the order of 20–45 MPa for the quartz+2 feldspars constraint and on the order of 25–100 MPa for the quartz+1 feldspar constraint; we suggest actual errors are closer to the lower bounds of these ranges. We investigate the effect of fluid saturation in two ways: (1) By applying our procedure over a range of water contents for three glass compositions; we show that the effect of fluid saturation is more important at higher pressures (~300 MPa) than at lower pressures (~100 MPa), but reasonable pressure estimates can be derived irrespective of fluid saturation for geologically relevant H₂O concentrations >3 wt% and (2) by performing the same type of pressure determinations with a preliminary version of rhyolite-MELTS that includes a H₂O–CO₂ mixed fluid phase; we use a range of H₂O and CO₂ concentrations for two compositions characteristic of early-erupted and late-erupted Bishop Tuff glass inclusions and demonstrate that calculated pressures are largely independent of CO₂ concentration (for CO₂ <1,000 ppm), at least for relatively high H₂O contents, as expected in most natural magmas, such that CO₂ concentration can be effectively neglected for application of our method. Finally, we demonstrate that pressures calculated using the rhyolite-MELTS geobarometer compare well with those resulting from H₂O–CO₂ glass inclusion barometry and Al-in-hornblende barometry for an array of natural systems for which data have been compiled from the literature; the agreement is best for quartz-hosted glass inclusions, while matrix glass yields systematically lower rhyolite-MELTS pressures, suggestive of melt evolution during eruptive decompression.  相似文献   

Depositional architecture and evolution of progradationally stacked lobe complexes in the Eocene Central Basin of Spitsbergen   总被引：1，自引：0，他引：1  

Sten‐Andreas Grundvåg  Erik P. Johannessen  William Helland‐Hansen  Piret Plink‐Björklund 《Sedimentology》2014,61(2):535-569

The down‐dip portion of submarine fans comprises terminal lobes that consist of various gravity flow deposits, including turbidites and debrites. Within lobe complexes, lobe deposition commonly takes place in topographic lows created between previous lobes, resulting in an architecture characterized by compensational stacking. However, in some deep water turbidite systems, compensational stacking is less prominent and progradation dominates over aggradation and lateral stacking. Combined outcrop and subsurface data from the Eocene Central Basin of Spitsbergen provide a rare example of submarine fans that comprise progradationally stacked lobes and lobe complexes. Evidence for progradation includes basinward offset stacking of successive lobe complexes, a vertical change from distal to proximal lobe environments as recorded by an upward increase in bed amalgamation, and coarsening and thickening upward trends within the lobes. Slope clinoforms occur immediately above the lobe complexes, suggesting that a shelf‐slope system prograded across the basin in concert with deposition of the lobe complexes. Erosive channels are present in proximal axial lobe settings, whereas shallow channels, scours and terminal lobes dominate further basinward. Terminal lobes are classified as amalgamated, non‐amalgamated or thin‐bedded, consistent with turbidite deposition in lobe axis, off‐axis and fringe settings, respectively. Co‐genetic turbidite–debrite beds, interpreted as being deposited from hybrid sediment gravity flows which consisted of both turbulent and laminar flow phases, occur frequently in lobe off‐axis to fringe settings, and are rare and poorly developed in channels and axial lobe environments. This indicates bypass of the laminar flow phase in proximal settings, and deposition in relative distal unconfined settings. Palaeocurrent data indicate sediment dispersal mainly towards the east, and is consistent with slope and lobe complex progradation perpendicular to the NNW–SSE trending basin margin.  相似文献