Abrupt climatic changes and an unstable transition into a late Holocene Thermal Decline: a multiproxy lacustrine record from southern Sweden     

Catherine A. Jessen  Mats Rundgren  Svante Bjrck  Dan Hammarlund 《第四纪科学杂志》2005,20(4):349-362

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Species composition and dietary relationships in a brackish shallow water fish assemblage in the Bothnian Sea,Sweden     

Staffan Thorman  Anne-Marie Wiederholm 《Estuarine, Coastal and Shelf Science》1984,19(3):359-371

A nearshore fish assemblage inhabiting a shallow bay in the southern Bothnian Sea, Sweden, with demanding environmental conditions (c. 5‰; >15°C during 4 months 1980 and 1 month 1981) was studied during a two-year period, in 1980 and 1981. Seasonal distribution patterns, dietary relationships, and growth rates were studied in Pungitius pungitius (L.), Pomatoschistus minutus (Pallas.), Gasterosteus aculeatus (L.), Phoxinus phoxinus (L.), Pomatoschistus microps (Krøyer) and Gobius niger L. The structure of the juvenile populations changed both over seasons and years but the adult populations remained constant. Lower water temperature, fewer individuals, lower and delayed fish growth, and lower interspecific food overlaps were found in 1981 compared to 1980. Few significant correlations were found in both years between the following community parameters: diversity, niche width, food overlap, and the proportion of each species in the fish assemblage.According to these results it is suggested that food competition and resource partitioning were of minor importance for the structuring of the fish community in the present area. Rather, the extreme salinity and the fluctuations in temperature regulated the fish populations. One may conclude that the populations of juveniles were more influenced by short-term changes in the environment than those of the adults.  相似文献   

Late Holocene climate change in central Sweden inferred from lacustrine stable isotope data     

Sofia Andersson  Gunhild Rosqvist  Melanie j. leng  Stefan Wastegård  Maarten Blaauw 《第四纪科学杂志》2010,25(8):1305-1316

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Defining geographical mobility: Perspectives from higher education     

《Geoforum》2017

Context is generally overlooked when selecting measures to define geographical mobility in mobility and migration research. This paper contributes to a discussion on the importance of context when defining geographical mobility and draws on examples from higher education in Sweden. Using binary logistic regression, statistical outcomes are compared when different measures of mobility to and mobility from higher education are employed. The measures produce different statistical outcomes, and these differences are illuminated when comparing results of common measures of mobility (e.g. crossing administrative boundaries or moving a certain distance) against two measures constructed specifically for Swedish higher education-related mobility. The results indicate that using municipality boundaries for measuring mobility in the Swedish higher education context is particularly inappropriate because the measure does not differentiate commuters from movers. This challenge surfaces because mobility must be determined in relation to the locations of students’ higher education institutions since administratively registered moves are unreliable in the educational context. These findings emphasize the importance of considering the geographical locations and characteristics of higher education institutions in addition to feasible commuting possibilities in research on higher education-related mobility. The two measures developed for the Swedish higher education context are identified as most appropriate because they center on the geographical distribution of higher education, and this distribution is perceived as having an important role in influencing mobility in this context. Consequently, this study accentuates the need for considering the geographical arrangement of resources (e.g. schools, hospitals) relevant to the context under investigation when determining measures to define mobility.  相似文献   

Climate and causation in the Swedish Iron Age: learning from the present to understand the past     

《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2012,112(2):126-134

The paper reassesses the role of climate as a factor shaping changes in settlement and landscape in the Swedish Iron Age (500 BC–AD 1050). Two reasons motivate this re-evaluation. First, high-resolution data based on climate proxies from the natural sciences are now increasingly available. Second, the climate-related social sciences have yielded conceptual and theoretical developments regarding vulnerability and adaptability in the present and recent past, creating new ways to analyse the effects of climatic vs. societal factors on societies in the more distant past. Recent research in this field is evaluated and the explicitly climate deterministic standpoint of many recent natural science texts is criticized. Learning from recent approaches to climate change in the social sciences is crucial for understanding society–climate relationships in the past. The paper concludes that we are not yet in a position to fully evaluate the role of the new evidence of abrupt climate change in 850 BC, at the beginning of the Iron Age. Regarding the crisis in the mid-first millennium AD, however, new climate data indicate that a dust veil in AD 536–537 might have aggravated the economic and societal crisis known from previous research.  相似文献   

160 Ma of magmatic/hydrothermal and metamorphic activity in the Gällivare area: Re–Os dating of molybdenite and U–Pb dating of titanite from the Aitik Cu–Au–Ag deposit, northern Sweden     

Christina Wanhainen  Kjell Billström  Olof Martinsson  Holly Stein  Roger Nordin 《Mineralium Deposita》2005,40(4):435-447

Host rocks to the Aitik Cu–Au–Ag deposit in northern Sweden are strongly altered and deformed Early Proterozoic mica(-amphibole) schists and gneisses. The deposit is characterised by numerous mineralisation styles, vein and alteration types. Four samples were selected for Re–Os molybdenite dating and 12 samples for U–Pb titanite dating in order to elucidate the magmatic/hydrothermal and metamorphic history following primary ore deposition in the Aitik Cu–Au–Ag deposit. Samples represent dyke, vein and alteration assemblages from the ore zone, hanging wall and footwall to the deposit. Re–Os dating of molybdenite from deformed barite and quartz veins yielded ages of 1,876±10 Ma and 1,848±8 Ma, respectively. A deformed pegmatite dyke yielded a Re–Os age of 1,848±6 Ma, and an undeformed pegmatite dyke an age of 1,728±7 Ma. U–Pb dating of titanite from a diversity of alteration mineral associations defines a range in ages between 1,750 and 1,805 Ma with a peak at ca. 1,780 Ma. The ages obtained, together with previous data, bracket a 160-Ma (1,890–1,730 Ma) time span encompassing several generations of magmatism, prograde to peak metamorphism, and post-peak cooling; events resulting in the redistribution and addition of metals to the deposit. This multi-stage evolution of the Aitik ore body suggests that the deposit was affected by several thermal events that ultimately produced a complex ore body. The Re–Os and U–Pb ages correlate well with published regional Re–Os and U–Pb age clusters, which have been tied to major magmatic, hydrothermal, and metamorphic events. Primary ore deposition at ca. 1,890 Ma in connection with intrusion of Haparanda granitoids was followed by at least four subsequent episodes of metamorphism and magmatism. Early metamorphism at 1,888–1,872 Ma overlapping with Haparanda (1,890–1,880 Ma) and Perthite-monzonite (1,880–1,870 Ma) magmatism clearly affected the Aitik area, as well as late metamorphism and Lina magmatism at 1,810–1,774 Ma and TIB1 magmatism at 1,800 Ma. The 1,848 Ma Re–Os ages obtained from molybdenite in a quartz vein and pegmatite dyke suggests that the 1,850 Ma magmatism recorded in parts of northern Norrbotten also affected the Aitik area.  相似文献   

Landscape preservation under Fennoscandian ice sheets determined from in situ produced Be and Al     

Derek Fabel  Arjen P. Stroeven 《Earth and Planetary Science Letters》2002,201(2):397-406

Some areas within ice sheet boundaries retain pre-existing landforms and thus either remained as ice free islands (nunataks) during glaciation, or were preserved under ice. Differentiating between these alternatives has significant implications for paleoenvironment, ice sheet surface elevation, and ice volume reconstructions. In the northern Swedish mountains, in situ cosmogenic ¹⁰Be and ²⁶Al concentrations from glacial erratics on relict surfaces as well as glacially eroded bedrock adjacent to these surfaces, provide consistent last deglaciation exposure ages (∼8-13 kyr), confirming ice sheet overriding as opposed to ice free conditions. However, these ages contrast with exposure ages of 34-61 kyr on bedrock surfaces in these same relict areas, demonstrating that relict areas were preserved with little erosion through multiple glacial cycles. Based on the difference in radioactive decay between ²⁶Al and ¹⁰Be, the measured nuclide concentration in one of these bedrock surfaces suggests that it remained largely unmodified for a minimum period of 845₋₄₁₈⁺⁴⁶¹ kyr. These results indicate that relict areas need to be accounted for as frozen bed patches in basal boundary conditions for ice sheet models, and in landscape development models. Subglacial preservation also implies that source areas for glacial sediments in ocean cores are considerably smaller than the total area covered by ice sheets. These relict areas also have significance as potential long-term subglacial biologic refugia.  相似文献   

The emergence of a post-industrial music economy? Music and ICT synergies in Stockholm, Sweden     

Dominic Power  Johan Jansson 《Geoforum》2004,35(4):425-439

Research into the music industry has for a long time been almost exclusively dominated by a focus on the production of albums and songs. In recent years, however, cities such as Stockholm have seen the growth of a profitable and varied music services industry producing everything from remixes to music marketing strategies. Standing at the forefront of this growth industry are a large number of firms attempting to combine in innovative ways music and ICT. This can take a variety of forms, for instance: selling and distributing music over the internet; web design and computerised advertising services tailored to music products; software design focused on multimedia products and virtual instruments; high-tech post-production and mixing services; and virtual centres and communities of music industry actors. The article will examine these activities within the city in attempt to measure the direction and cohesiveness of the emerging sector. The article concludes by arguing that these type of new industrial synergies tell us much about the way industrial innovations are formed in an interindustry and inter-cluster environment, and the future competitiveness and shape of the music industry. In particular, the article argues that evidence from Stockholm points to the emergence of a post-industrial musical economy.  相似文献   

Crustal conductivity anomalies in central Sweden and southwestern Finland     

K. Pajunpää  I. Lahti  B. Olafsdottir  T. Korja  BEAR Working Group 《Geophysical Journal International》2002,150(3):695-705

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Summary of project TOR: delineation of a stepwise, sharp, deep lithosphere transition across Germany–Denmark–Sweden     

TOR Working Group  S. Gregersen  P. Voss 《Tectonophysics》2002,360(1-4):61-73

Project Tor (Teleseismic Tomography across the Tornquist Zone in Germany–Denmark–Sweden) is now producing results. We are able to detect very significant deep lithosphere differences, and we can now discuss the sharpness laterally. In 1996–1997, our 120 seismographs constituted the largest seismic antenna ever in Europe. The Tor area was chosen along a well-studied crustal profile of an earlier project, and the inversion efforts are concentrated on the deep lithosphere and asthenosphere differences to depths around 300 km. The Tor investigation can be called two-and-a-half-dimensional, as it has a 900-km profile length with 100 km width plus a few seismographs off the profile. The Tor data have been subjected to P-wave travel time tomography, surface wave and receiver function analysis as well as anisotropy and scattering measurements. Through ray tracing in a compiled crustal model and subtraction of the modelled travel time anomalies, the influence of the lower lithosphere/asthenosphere on the seismic rays from distant earthquakes is being established. Travel time tomography results confirm very large lateral lithosphere differences of 4–6% in P-wave velocity. For several events of the large data base, it is demonstrated that the observed P-wave travel time anomalies of 1–2 s can be divided almost equally between known crustal effects and lower lithosphere/asthenosphere differences, which then must account for about 1 s of the travel time differences. The transition is interpreted to be sharp and steep in two places. It goes all the way through the lithosphere at the northern rim of the Tornquist Zone near the border between Sweden and Denmark, and here the lithosphere difference is large. A smaller lithosphere difference is found near the southern edge of the Ringkøbing-Fyn High just north of the border between Denmark and Germany. Also, this transition is sharp and steep, and goes all through the lithosphere. These two sharp transitions divide the Tor region into three different lithosphere structures distinguishable in P-wave travel time tomography, surface wave dispersion, P- and S-wave anisotropy, and partly in P-wave scattering.  相似文献