A REGIONAL INVENTORY OF ROCK GLACIERS AND ICE‐CORED MORAINES IN NORWAY     

KARIANNE S. LILLEØREN  BERND ETZELMÜLLER 《Geografiska Annaler: Series A, Physical Geography》2011,93(3):175-191

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Late‐glacial to Holocene environmental changes and climate variability: evidence from Voldafjorden,western Norway     

H. P. Sejrup  H. Haflidason  T. Flateb  D. Klitgaard Kristensen  K. Grsfjeld  E. Larsen 《第四纪科学杂志》2001,16(2):181-198

Sedimentological, micropalaeontological (benthic foraminifers and dinoflagellate cysts), stable isotope data and AMS ¹⁴C datings on cores and surface samples, in addition to acoustic data, have been obtained from Voldafjorden, western Norway. Based on these data the late glacial and Holocene sedimentological processes and variability in circulation and fjord environments are outlined. Glacial marine sedimentation prevailed in the Voldafjorden between 11.0 kyr and 9.2 kyr BP (radiocarbon years). In the later part of the Allerød period, and for the rest of the Holocene, there was deposition of fine‐grained normal marine sediments in the fjord basin. Turbidite layers, recorded in core material and on acoustic profiles, dated to ca. 2.1, 6.9–7.6, ca. 9.6 and ca. 11.0 kyr BP, interrupted the marine sedimentation. The event dated to between 6.9 and 7.6 kyr BP probably corresponds to a tsunami resulting from large‐scale sliding on the continental margin off Norway (the Storegga Tsunami). During the later part of the Allerød period, Voldafjorden had a strongly stratified water column with cold bottom water and warm surface water, reaching interglacial temperatures during the summer seasons. During the Younger Dryas cold event there was a return to arctic sea‐surface summer temperatures, possibly with year‐round sea‐ice cover, the entire benthic fauna being composed of arctic species. The first strong Holocene warming, observed simultaneously in bottom and sea‐surface temperature proxies, occurred at ca. 10.1 kyr BP. Bottom water proxies indicate two cold periods, possibly with 2°C lowering of temperatures, at ca. 10.0 (PBO 1) and at 9.8 kyr BP (PBO 2). These events may both result from catastrophic outbursts of Baltic glacial lake water. The remainder of the Holocene experienced variability in basin water temperature, indicated by oxygen isotope measurements with an amplitude of ca. 2°C, with cooler periods at ca. 8.4–9.0, 5.6, 5.2, 4.6, 4.2, 3.5, 2.2, 1.2 and 0.4–0.8 kyr BP. Changes in the fjord hydrology through the past 11.3 kyr show a close correspondence, both in amplitude and timing of events, recorded in cores from the Norwegian Sea region and the North Atlantic. These data suggest a close relationship between fjord environments and variability in large‐scale oceanic circulation. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Acidity and organic carbon in lake water: variability and estimation of means     

John F. Boyle 《Journal of Paleolimnology》1991,6(2):95-101

The demand for a single value to characterize the pH (and other chemical variables) of a lake, in order to calibrate palaeolimnological reconstructions, requires an answer to the question of whether means should be of untransformed or log data. The temporal frequency distributions of acidity and organic carbon in seven rivers and lakes (surface samples) in Norway are approximately lognormal. Thus log means describe the distributions better than untransformed means. Estimated standard deviations, which are similar for the rivers and lakes, are independent of the mean values. Restricting observations to the autumn does not result in better estimation of mean annual values.  相似文献   

Discovery of eclogite facies carbonate rocks from the Lindås Nappe, Caledonides, Western Norway     

T. M. Boundy  C. L. Donohue  E. J. Essene  K. Mezger  H. Austrheim 《Journal of Metamorphic Geology》2002,20(7):649-667

Eclogite facies carbonate rocks have been discovered associated with the granulite–eclogite transitional rocks within Bergen Arc system, Caledonian Orogen of western Norway. The local occurrences of marbles and calc‐silicates are found subparallel to the mafic eclogite facies shear zones on Holsnøy Island. Marbles contain the assemblage calcite (Ca_0.99Sr_0.01CO₃), calcian strontianite (Ca_0.18?0.44Sr_0.53?0.84CO₃), clinopyroxene (Jd_7?32), epidote/allanite (Ps_0?33), titanite, garnet (Alm_52?56Grs_28?33Pyp_11?16), barite (Ba_0.90?0.99Sr_0.01?0.10SO₄), celestine (Sr_0.67?0.98Ba_0.01?0.23Ca_0.01?0.11SO₄), and one apparently homogeneous grain of intermediate composition (Ba_0.49Ca_0.01Sr_0.50SO₄). Adjacent eclogites have clinopyroxene with similar jadeite contents (Jd_14?34) and similar garnet (Alm_51?60Grs_26?36Pyp_8?14) compositions. The marbles have high contents of Sr (9500–11000 p.p.m) and Y (115–130 p.p.m). However, low concentrations of some key trace elements (110–160 p.p.m. Ba and <5 p.p.m. Nb) appear to indicate that the marble is not a metamorphosed carbonatite. The ⁸⁷Sr/⁸⁶Sr ratios range from 0.7051 to 0.7059. Field and petrological relationships suggest that metasomatic reactions and fluids played a significant role in producing and/or modifying the marbles. The breakdown of scapolite in the granulite into carbonates and sulphates during eclogite facies metamorphism may have contributed to the metasomatic formation of the marbles along shear zones. Fluids involved during subduction are an important catalyst for metamorphism and are recognized to have played a critical role in the localized transformation from granulite to eclogite in the Holsnøy Island area. Thermobarometry indicates 640–690 °C and 18–20 kbar for adjacent eclogites and temperatures of 580–650 °C for the calc‐silicates. The marble assemblages are consistent with fluid that is dominantly comprised of H₂O (X_CO2 < 0.03) under high‐pressure conditions. Phase equilibria of the marbles constrain the fO₂ of the fluids and imply oxidizing conditions of the deep crustal fluids. At present the source of the fluids remains unresolved. The results provide additional insights into the variable and evolving nature of fluids related to subduction and high‐pressure metamorphism.  相似文献   

Late Weichselian and Holocene sediment flux and sedimentation rates in Andfjord and Vågsfjord,North Norway     

Liv Plassen  Tore O. Vorren 《第四纪科学杂志》2002,17(2):161-180

Late Weichselian and Holocene sediment flux and sedimentation rates in a continental‐shelf trough, Andfjord, and its inshore continuation, Vågsfjord, North Norway, have been analysed. The study is based on sediment cores and high‐resolution acoustic data. Andfjord was deglaciated between 14.6 and 13 ¹⁴C kyr BP (17.5 and 15.6 calibrated (cal.) kyr BP), the Vågsfjord basin before 12.5 ¹⁴C kyr BP (14.7 cal. kyr BP), and the heads of the inner tributary fjords about 9.7 ¹⁴C kyr BP (11.2 cal. kyr BP). In Andfjord, five seismostratigraphical units are correlated to a radiocarbon dated lithostratigraphy. Three seismostratigraphical units are recognised in Vågsfjord. A total volume of 23 km³ post‐glacial glacimarine and marine sediments was mapped in the study area, of which 80% are of Late Weichselian origin. Sedimentation rates in outer Andfjord indicate reduced sediment accumulation with increasing distance from the ice margin. The Late Weichselian sediment flux and sedimentation rates are significantly higher in Vågsfjord than Andfjord. Basin morphology, the position of the ice front and the timing of deglaciation are assumed to be the reasons for this. Late Weichselian sedimentation rates in Andfjord and Vågsfjord are comparable to modern subpolar glacimarine environments of Greenland, Baffin Island and Spitsbergen. Downwasting of the Fennoscandian Ice Sheet, and winnowing of the banks owing to the full introduction of the Norwegian Current, caused very high sedimentation rates in parts of the Andfjord trough at the Late Weichselian–Holocene boundary. Holocene sediment flux and sedimentation rates in Andfjord are about half the amount found in Vågsfjord, and about one‐tenth the amount of Late Weichselian values. A strong bottom current system, established at the Late Weichselian–Holocene boundary, caused erosion of the Late Weichselian sediments and an asymmetric Holocene sediment distribution. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Temporal englacial water content variability associated with a rapidly retreating glacier     

Jane K. Hart  Kathryn C. Rose  Kirk Martinez 《地球表面变化过程与地形》2011,36(9):1230-1239

This study uses a combination of evidence from ground penetrating radar, borehole, video, and wireless probe data to assess temporal changes in englacial water content associated with Briksdalsbreen, a rapidly retreating Norwegian glacier. Over a 13 day period in 2006, ice radar‐wave velocity varied between 0·135 m/ns (± 0·009) and 0·159 m/ns (± 0·003), and water content from 7·8% (+2·6, ?2·8) to 2·5% (+0·9, ?1·1) [derived from the Looyenga (Physica 31 (3): 401–406, 1965) formula]. It is suggested that during warm precipitation free days, void spaces within the glacier become filled with water, resulting in low radar‐wave velocity. This stored water then drained during cold, high precipitation days, allowing the radar‐wave velocity to rise. These changes in englacial storage were caused by the enhanced crevassing generated by the newly floating ice margin, and were associated with accelerated glacier retreat. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Innovation by co-evolution in natural resource industries: The Norwegian experience     

Bjørnar Sæther  Arne Isaksen 《Geoforum》2011,42(3):373-381

Some resource-based economies become wealthy while others stay poor and Norway belongs to the first category. This paper argues that part of the answer to why Norway has managed to benefit from its rich natural resources is found in the formation of a well-functioning national innovation system. The paper integrates the innovation system approach with a historical approach through the concept of co-evolution. The empirical study investigates how innovation systems evolve in natural resource industries through analysing the co-evolution between industry, knowledge organisations and national policy in the Norwegian aluminium and petroleum sectors. Parallels are found in the development of these two sectors, which are: (i) the deliberate use of concession laws to seize value creation and technological development from foreign direct investments, (ii) the establishment and prioritisation of state-owned companies and (iii) the more or less intentional formation of a national innovation system. The paper points to the relevance of analysing the historical evolution of national innovation systems to understand the creation of their specific path-dependent characteristics, to analyse how policy influences the creation and working of innovation systems, to use a multilevel approach in studies of innovation systems and to consider how innovation processes in different industries are linked in value chains and through knowledge flows.  相似文献   

A multi-proxy approach to assessing isolation basin stratigraphy from the Lofoten Islands, Norway     

Nicholas L. Balascio  Zhaohui Zhang  Raymond S. Bradley  Svein Olaf Dahl  Jostein Bakke 《Quaternary Research》2011,75(1):288-300

This study takes a comprehensive approach to characterizing the isolation sequence of Heimerdalsvatnet, a coastal lake in the Lofoten Islands, northern Norway. We use established methods and explore new techniques to assess changes in marine influence. Bathymetric and sub-bottom profiles were acquired to examine basin-wide sedimentation and a 5.8 m sediment core spanning the last 7800 cal yr BP was analyzed. We measured magnetic susceptibility, bulk organic matter properties, molecular biomarkers, diatom assemblages, and elemental profiles acquired by scanning X-ray fluorescence. These characteristics of the sediment reflect detailed changes in salinity and water column conditions as the lake was progressively isolated. Three distinct litho/chemo-stratigraphic units represent a restricted marine phase (7800-6500 cal yr BP), a transitional phase characterized by intermittent marine influence (6500-4900 cal yr BP), and complete isolation and freshwater sedimentation (4900 cal yr BP to present). Although there are uncertainties in the estimate of the threshold elevation of the lake, the timing of these phases generally corresponds with previous interpretations of the local relative sea-level history. This record captures sea-level regression following the Tapes transgression and supports the interpretation of a subsequent sea-level stillstand, dated in Heimerdalsvatnet from 6500 to 4900 cal yr BP.  相似文献   

Mobility encounter: The narratives of Burmese refugees in Norway     

Yee Yee Swe 《Norsk geografisk tidsskrift. Norwegian journal of geography》2013,67(4):229-238

The article examines the lived experiences of Burmese refugees in Norway in order to understand how they experience integration into local society and how they manage their transnational lives in new socio-economic, political, and cultural contexts. The examination is performed from the perspective of mobility as the entanglement of movement, representation, and practice. In teasing out the refugees' various experiences, the author emphasizes the diversity of migrant groups in terms of their ethnicity, religion, gender, and age, as well as multiple dimensions of mobilities. The complex politics of mobility – how different mobilities are produced, practised, and regulated in relation to issues such as transnational migration, diasporic cultures, and communication technologies – is seen as underlying the narratives of Burmese refugees in Norway. Their narratives equate mobilities with escape from poverty, highlighting the linkage that mobility has with poverty and development. The discussion reveals the potential for divisiveness within wider society in Norway, and it is argued that a nuanced understanding of how mobilities are differentially accessed within immigrant groups is essential for conceiving a multicultural society in Norway.  相似文献   

LANDSLIDE‐GLACIER INTERACTION IN A NEOPARAGLACIAL SETTING AT TVERRBYTNEDE,JOTUNHEIMEN, SOUTHERN NORWAY     

GERAINT OWEN  JOHN F. HIEMSTRA  JOHN A. MATTHEWS  LINDSEY J. MCEWEN 《Geografiska Annaler: Series A, Physical Geography》2010,92(4):421-436

A tongue‐like, boulder‐dominated deposit in Tverrbytnede, upper Visdalen, Jotunheimen, southern Norway, is interpreted as the product of a rock avalanche (landslide) due to its angular to subangular boulders, surface morphology with longitudinal ridges, down‐feature coarsening, and cross‐cutting relationship to ‘Little Ice Age’ moraines. The rock avalanche fell onto glacier ice, probably channelled along a furrow between two glaciers, and stopped on the glacier foreland, resulting in its elongated shape and long runout distance. Its distal margin may have become remobilized as a rock glacier, but a rock glacier origin for the entire landform is discounted due to lack of source debris, presence of matrix, lack of transverse ridges, and sparcity of melt‐out collapse pits. Lichenometric dating of the deposit indicates an approximate emplacement age of ad 1900. Analysis highlights the interaction of rock‐slope failures and glaciers during deglacierization in a neoparaglacial setting, with reduced slope stability due to debuttressing and permafrost degradation, and enhanced landslide mobility due to flow over a glacier and topographic channelling. Implications for the differentiation of relict landslides, moraines and rock glaciers are discussed and interrelationships between these landforms are considered in terms of an ice‐debris process continuum.  相似文献