From the Early Paleozoic Platforms of Baltica and Laurentia to the Caledonide Orogen of Scandinavia and Greenland   总被引：1，自引：0，他引：1  

David G. Gee Haakon Fossen Niels Henriksen Anthony K. Higgins 《《幕》》2008,31(1):44-51

The Caledonide Orogen in the Nordic countries is exposed in Norway, western Sweden, westernmost Finland, on Svalbard and in northeast Greenland. In the mountains of western Scandinavia, the structure is dominated by E-vergent thrusts with allochthons derived from the Baltoscandian platform and margin, from outboard oceanic （lapetus） terranes and with the highest thrust sheets having Laurentian affinities. The other side of this bivergent orogen is well exposed in northeastern Greenland, where W-vergent thrust sheets emplace Laurentian continental margin assemblages onto the platform. Svalbard＇s Caledonides are disrupted by late Caledonian faults, but have close affinity with the Laurentian margin in Northeast Greenland. Only Svalbard＇s Southwestern terrane is foreign to this margin, showing affinity, to the Pearya terrane of northern Ellesmere Island in arctic Canada. Between the margins of western Scandinavia and eastern Greenland, the wide continental shelves, now covered by late Paleozoic and younger successions, are inferred to be underlain by the Caledonide hinterland, probably incorporating substantial Grenville-age basement. In northernmost Norway, the NE-trending Caledonian thrust front truncates the NW-trending Neoproterozoic Timanide orogen of northwest Russia. Much of the central and eastern parts of the Barents Shelf are thought to be underlain by Caledonian-deformed Timanide basement.
Caledonian orogeny in Norden resulted from the closure of the Iapetus Ocean and Scandian collision of continent Baltica with Laurentia. Partial subduction of the Baltoscandian margin beneath Laurentia in the midlate Silurian was followed by rapid exhumation of the highly metamorphosed hinterland in the early Devonian, and deposition of Old Red Sandstones in intramontane basins. Late Scandian collapse of the orogen occurred on major extensional detachments, with defor mation persisting into the late Devonian.  相似文献   

Observations of thermospheric neutral winds within the polar cusp and the auroral oval using a Doppler imaging system (DIS)     

D. Rees  R. W. Smith  F. Signernes  K. Henriksen  U. Brandstrom  M. Harris  G. Maskall 《Annales Geophysicae》1998,16(11):1461-1474

Two Doppler imaging systems (DIS) or wide-field imaging Fabry-Perot interferometers (FPI), have recently been commissioned, one at the Auroral Station, Adventdalen, Longyearbyen, Svalbard, and the second at the IRF, Kiruna, Sweden. These instruments can provide wide-field (600 * 800 km) images of neutral wind flows in the upper thermosphere, by measuring the Doppler shift of the atomic oxygen forbidden near 630 nm, which is emitted from an altitude of approximately 240 km. From the instrument in Svalbard, at mid-winter, it is possible to observe the dayside polar cusp and the polar cap throughout the entire day, whereas from Kiruna, the night-time auroral oval is observable during the hours of darkness. Measurements of thermospheric dynamics from the DIS can be used in conjunction with observations of ionospheric plasma flows and thermal plasma densities by the EISCAT-Svalbard radar (ESR) and by EISCAT, along with other complementary observations by co-located instruments such as the auroral large-scale imaging system (ALIS). Such combined data sets will allow a wide range of scientific studies to be performed concerning the dynamical response of the thermosphere and ionosphere, and the important energetic and momentum exchange processes resulting from their complex interactions. These processes are particularly important in the immediate vicinity of the polar cusp and within the auroral oval. Early results from Svalbard in late 1995 will be discussed. The DIS in Kiruna observed two interesting geomagnetic disturbances in early 1997, the minor geomagnetic storm of 10, 11 January, and the disturbed period from 7–10 February. During these events, the thermospheric wind response showed some interesting departures from the average behaviour, which we attribute to the result of strong and variable Lorenz forcing (ion drag) and Joule and particle heating during these geomagnetic disturbances.  相似文献   

Geographic variation of Sebastes mentella in the Northeast Arctic derived from a morphometric approach     

Saborido-Rey  Fran; Nedreaas  Kjell H. 《ICES Journal of Marine Science》2000,57(4):965-975

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Genetic studies of redfish (Sebastes spp.) from Icelandic and Greenland waters     

Nedreaas  Kjell; Johansen  Torild; Naevdal  Gunnar 《ICES Journal of Marine Science》1994,51(4):461-467

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The Importance of Posidonia oceanica and Cymodocea nodosa as Contributors of Free Amino Acids in Water and Sediment of Seagrass Beds     

Niels O. G.  Jørgensen  T. Henry  Blackburn  Kai  Henriksen Daniel  Bay 《Marine Ecology》1981,2(2):97-112

Abstract. Dissolved free amino acids (DFAA) were measured in sediment porewater and overlying sea water in seagrass beds of Posidonia oceanica and Cymodocea nodosa at a water depth of 8–10 m in Corsica, France. In the sea water, DFAA concentrations from 0.5 to 1.9μM were found. Lowest concentrations occurred in the afternoon in surface water samples, while higher concentrations were measured in morning surface samples and in all bottom samples. The most abundant amino acids were serine, glycine, and alanine. In the sediment, the upper 4cm contained the highest concentrations of DFAA (177nmol cm^-3 or 367 μM), while lower concentrations (<50nmol cm^-3 or 104 μM) prevailed deeper in the sediment. Glycine, glutamic acid, alanine, and β-alanine were the major components of the DFAA. The photosynthetic activity of the seagrasses influenced sediment porewater pools of DFAA. When a Posidonia bed was covered with a black polyethylene shield, the interstitial amino acids were reduced at a rate of 16nmol cm^-2 h^-1 (0-10cm depth). Conversely, extended daylight (floodlight) increased the DFAA pool in sediment depths below 4 cm. Free amino acids were released to the overlying sea water from both seagrass sediment and individual shoots, the rates being highest in the dark. The present investigation indicates that a substantial portion of the N-cycling of the seagrass sediment includes free amino acids.  相似文献   

裤式拖网法校核试验和网形分析     

唐衍力  梁振林  Arill Engas  Kjell Gamst 《中国海洋大学学报(自然科学版)》2003,33(5):695-700

裤式拖网法是渔具选择性研究方法之一 ,其网形和校核试验于 2 0 0 2年 1月在挪威特鲁姆瑟海湾进行。在 1 1 5～ 2 70 m的水深范围内 ,测量的裤式拖网网口的水平扩张平均为 (2 3.2 7± 0 .2 6) m,网口高度为 (6.53± 0 .1 2 ) m;右网囊对左网囊的虾渔获物重量之比为 1 .0 0± 0 .0 4 ,右网囊对左网囊的渔获物尾数之比为 1 .0 8± 0 .0 9,渔获物种类及体长频率分布相似 ,基本符合用裤式拖网法进行选择性研究的要求  相似文献   

Herring at the Arctic front: influence of temperature and prey on their spatio-temporal distribution and migration     

Leif Nøttestad  Ole Arve Misund  Webjørn Melle  Bente K. Hoddevik Ulvestad  & Kjell Arild Orvik 《Marine Ecology》2007,28(S1):123-133

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A comparative acoustic-abundance estimation of pelagic redfish (Sebastes mentella) from hull-mounted and deep-towed acoustic systems     

Dalen  John; Nedreaas  Kjell; Pedersen  Ronald 《ICES Journal of Marine Science》2003,60(3):472-479

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MODIS-NDVI-based mapping of the length of the growing season in northern Fennoscandia     

Stein Rune Karlsen  Anne Tolvanen  Eero Kubin  Jarmo Poikolainen  Kjell Arild Høgda  Bernt Johansen  Fiona S. Danks  Paul Aspholm  Frans Emil Wielgolaski  Olga Makarova 《International Journal of Applied Earth Observation and Geoinformation》2008

Northern Fennoscandia is an ecologically heterogeneous region in the arctic/alpine-boreal transition area. Phenology data on birch from 13 stations and 16-day MODIS-NDVI composite satellite data with 250 m resolution for the period 2000 to 2006 were used to map the growing season. A new combined pixel-specific NDVI threshold and decision rule-based mapping method was developed to determine the onset and end of the growing season. A moderately high correlation was found between NDVI data and birch phenology data. The earliest onset of the growing season is found in the narrow strip of lowland between the mountains and the sea along the coast of northern Norway. The onset follows a clear gradient from lowland to mountain corresponding to the decreasing temperature gradient. In autumn, the yellowing of the vegetation shows a more heterogeneous pattern. The length of the growing season is between 100 and 130 days in 55% of the study area.  相似文献   

Rare earth elements in some igneous rocks in the Oslo rift, Norway     

Else-Ragnhild Neumann  Arild O. Brunfelt  Kjell G. Finstad 《Lithos》1977,10(4):311-319

Rare earth element (REE) concentrations have been determined for 27 plutonic rocks in the Permian Oslo rift, including kjelsåsite/larvikites, lardalites, nordmarkites, ekerites and Drammen granites.

The kjelsåsite/larvikites from different parts of the rift have very similar REE concentrations and must be derived from a source or sources homogeneous with respect to REE.

The genetic relations between the kjelsåsite/larvikites and the other rocks were tested by comparing observed REE enrichment factors with calculated ones based on hypothetical fractionation relations derived from petrographic mixing calculations. Several of the analyzed nordmarkites may be derived from kjelsåsitic/larvikitic parent magmas: the ekerites are closely related to the nordmarkites.  相似文献