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1.
HEIKKI SEPPÄ H. JOHN B. BIRKS ANNE E. BJUNE ATLE NESJE 《Boreas: An International Journal of Quaternary Research》2010,39(4):649-654
Seppä, H., Birks, H. J. B., Bjune, A. E. & Nesje, A. 2010: Current continental palaeoclimatic research in the Nordic region (100 years since Gunnar Andersson 1909) – Introduction. Boreas, Vol. 39, pp. 649‐654. 10.1111/j.1502‐3885.2010.00170.x. ISSN 0300‐9483. 相似文献
2.
ATLE NESJE SVEIN OLAF DAHL HENRIETTE LINGE COLIN K. BALLANTYNE DANNY MCCARROLL EDWARD J. BROOK GRANT M. RAISBECK FRANCOISE YIOU 《Boreas: An International Journal of Quaternary Research》2007,36(3):227-239
Blockfields, weathering boundaries and marginal moraines have been mapped along a longitudinal transect from northern Andøya to Skånland in northern Norway. The degree of rock-surface weathering above and below glacial trimlines, clay-mineral assemblages and surface exposure dating based on in situ cosmogenic 10 Be have been used to reconstruct the vertical dimensions and timing of the Last Glacial Maximum (LGM) of the Scandinavian Ice Sheet in this region. The cosmogenic exposure dates suggest that the lower blockfield boundary/trimline along the Andøya-Skånland transect represents the upper limit of the Late Weichselian ice sheet, with an average surface gradient of c . 9.5 m/km. The surface exposure dates from Andøya pre-date the LGM, suggesting that the LGM ice sheet did not reach mountain plateaux at northwest Andøya. The results thus support evidence from lake sediment records that the northern tip of Andøya was not covered by the Scandinavian Ice Sheet during the LGM. 相似文献
3.
MORTEN SMELROR ATLE MØRK ERIC MONTEIL DAVID RUTLEDGE HAN LEEREVELD 《Polar research》1998,17(2):181-202
A new Lower Cretceous lithostratigraphic unit of the Western Barents Shelf, named the Klippfisk Formation, is formally introduced. The formation represents a condensed carbonate succession deposited on platform areas and structural highs, where it consists of limestones and marls, often glauconitic. The limestones may have a nodular appearance, and fossil debris, which are dominated by Inoceramus prisms, may be abundant. The Klippfisk Formation is composed of two members: the Kutling Member defined herein from cores drilled on the Bjarmeland Platform, and the coeval Tordenskjoldberget Member described on Kong Karls Land. The base of the formation is defined by the abrupt decrease in gamma-ray intensity, where the dark shales of the underlying Hekkingen or Agardhfjellet formations are replaced by marls. It is often unconformable. The Klippfisk Formation is of Berriasian to Early Barremian age and appears to be time-transgressive over parts of the Western Barents Shelf (including Kong Karls Land). It passes laterally into the basinal Knurr Formation. On Kongsøya (Kong Karls Land) a thin shale unit, bounded by unconformities, earlier included in the Tordenskjoldberget Member, represents the northernmost extension of the overlying Kolje Formation in the Barents Shelf. 相似文献
4.
The Triassic succession of Bjørnøya (200 m) comprises the Lower Triassic Urd Formation (65 m) of the Sassendalen Group, and the Middle and Upper Triassic Skuld Formation (135 m) of the Kapp Toscana Group. These units are separated by a condensed '.'Middle Triassic sequence represented by a phosphatic remainé conglomerate (0.2m).
The Urd Formation consists of grey to dark grey shales with yellow weathering dolomitic beds and nodules. Palynology indicates the oldest beds to be Diencrian; ammonoid faunas in the middle and upper part of the formation arc of Smithian age. The organic content (c. 1 %) includes kerogen of land and marine origin, reflecting a shallow marine depositional environment.
The Skuld Formation is dominated by grey shales with red weathering siderite nodules. There are minor coarsening upwards sequences; the highest bed exposed is a 20 m thick, very fine-grained sandstone. Palynomorphs indicate a late Ladinian age for the lower part of the formation, and macrofossils and palynomorphs indicate Ladinian to Carnian ages for the upper part. Sedimentary structures, a sparse marine fauna and microplankton indicate deposition in a shallow marine environment. The organic residues contain dominantly terrestrially derived kerogen. 相似文献
The Urd Formation consists of grey to dark grey shales with yellow weathering dolomitic beds and nodules. Palynology indicates the oldest beds to be Diencrian; ammonoid faunas in the middle and upper part of the formation arc of Smithian age. The organic content (c. 1 %) includes kerogen of land and marine origin, reflecting a shallow marine depositional environment.
The Skuld Formation is dominated by grey shales with red weathering siderite nodules. There are minor coarsening upwards sequences; the highest bed exposed is a 20 m thick, very fine-grained sandstone. Palynomorphs indicate a late Ladinian age for the lower part of the formation, and macrofossils and palynomorphs indicate Ladinian to Carnian ages for the upper part. Sedimentary structures, a sparse marine fauna and microplankton indicate deposition in a shallow marine environment. The organic residues contain dominantly terrestrially derived kerogen. 相似文献
5.
ATLE MØRK GEIR ELVEBAKK ARNE W. FORSBERG MARK W. HOUNSLOW. HANS ARNE NAKREM. JORUNN OS VIGRAN WOLFGANG WEITSCHAT 《Polar research》1999,18(1):51-82
The Vikinghøgda Formation (250 m) is defined with a stratotype in Deltadalen-Vikinghøgda in central Spitsbergen. The Vikinghøgda Formation replaces the Vardebukta and Sticky Keep Formations of Buchan et al. (1965) and the lower part of the Barentsøya Formation of Lock et al. (1978) as extended geographically by Mørk, Knarud et al. (1982) in central Spitsbergen, Barentsøya and Edgeøya. The formation consists of three member: the Deltadalen Member (composed of mudstones with sandstones and siltstones), the Lusitaniadalen Member (dominated by mudstones with thin siltstone beds and some limestone concretions) and the Vendomdalen Member (composed of dark shales with dolomite interbeds and nodules). The Lusitaniadalen and Vendomdalen members replace the former Sticky Keep Formation/ Member in the siirne areu. The Vikinghøda Formation can be followed through central and eastern Spitsbergen to Barentøya and Edgeøya and includes all sediments between the chert-rich Kapp Starostin Formation (Permian) and the organic-rich shales of the Botneheia Formation (Middle Triassic). The subdivision into three members is also reflected in the organic carbon content and palynofacies. Upwards. each succeeding member becomes more distal, organic-rich and oil-prone than the one below.
The Vikinghøda Formation is well-dated by six ammonoid zones. although the transitional beds between the Deltadalen and Lusitaniadalen members lack age diagnostic macrofossils. Corresponding palynozonation and magnetustratigraphy have also been determined. The overall stratigraphical development correlates well with other key Triassic areas in the Arctic, although intervals in the late Dienerian and early Smithian may be condensed or missing. 相似文献
The Vikinghøda Formation is well-dated by six ammonoid zones. although the transitional beds between the Deltadalen and Lusitaniadalen members lack age diagnostic macrofossils. Corresponding palynozonation and magnetustratigraphy have also been determined. The overall stratigraphical development correlates well with other key Triassic areas in the Arctic, although intervals in the late Dienerian and early Smithian may be condensed or missing. 相似文献
6.
JOHN A. MATTHEWS SVEIN-OLAF DAHL MARK S. BERRISFORD ATLE NESJE P. QUENTIN DRESSER LISA DUMAYNE-PEATY 《第四纪科学杂志》1997,12(2):117-129
A stratigraphic succession of alternating peat and minerogenic sediments at the foot of a steep mountain slope provides the basis for the reconstruction of a preliminary colluvial history from the alpine zone of Jotunheimen, southern Norway. Layers of silty sand and sandy silt, typically 5–10 cm thick and interpreted as distal debris-flow facies, are separated by layers of peat that have been radiocarbon dated. Deposition from at least 7500 to about 3800 14C yr BP of predominantly minerogenic material suggests relatively infrequent but large-magnitude debris-flow events in an environment warmer and/or drier than today. Particularly low colluvial activity between about 6500 and 3900 14C yr BP was terminated by a succession of major debris-flow events between about 3800 and 3400 14C yr BP. Unhumified peats indicative of higher water tables, separate six debris-flows that occurred between about 3300 and 2300 14C yr BP and signify a continuing high frequency of colluvial activity. Uninterrupted peat accumulation between about 2400 and 1600 14C yr BP indicates reduced debris-flow activity; subsequent renewed activity appears to have culuminated in the ‘Little Ice Age’ after about 600 14C yr BP. This pattern of colluvial deposition demonstrates a long history of natural Holocene low-alpine landscape instability, suggests an increase first in the magnitude and then in the frequency of debris-flow activity coincident with late Holocene climatic deterioration, and points to the potential of debris-flow records as a unique source of palaeoclimatic information related to extreme rainfall events. © 1997 John Wiley & Sons, Ltd. 相似文献
7.
Crop contents of Svalbard Ptarmigan have been examined. For chicks younger than 25 days the crops contained almost exclusively bulbils of Polygonum viviparum . High incidence of this food item was also found in crops from adult birds during late summer and autumn (July-October). Midwinter (November-February) crops contained a mixture of plant species dominated by herbs like Saxifraga oppositifolia and S. cespitosa , but with a significant contribution from Salix polaris . The proportion of 5. polaris increased throughout the winter and became highly dominant in spring (May-June). During all seasons the birds ingested plant parts of high nutritional value. The change in crop content from P. viviparum to 5. polaris via different herbs was associated with a decrease in the content of crude protein from 20–25% in July-August to about 16% in March-April, and a corresponding increase in crude fibre from about 10% to about 15%. The content of inorganic constituents (P, Mg, Ca, K, Na) varied insignificantly with season and was fairly high. 相似文献
8.
DANNY McCARROLL ATLE NESJE 《Boreas: An International Journal of Quaternary Research》1993,22(3):255-265
Degree of rock surface weathering was measured on sites in Oldedalen and Brigsdalen, where dates of deglaciation have been estimated. and on an altitudinal transect on the slopes of Skåla. representing one of the highest supra-marine reliefs in western Norway. The Schmidt hammer is useful only for distinguishing sites deglaciated during the Little Ice Age from those deglaciated during the Lateglacial and early Holocene. Degree of roughness of granitic augen gneiss bedrock surfaces was quantified from profiles measured in situ using a micro-roughness-meter and profile gauge. There is a significant increase in surface roughness above a clear trimline at c. 1350 m a.s.I. but no significant increase above a higher trimline previously proposed as the vertical limit of the last ice sheet in this area (c. 1560 m a.s.I.). The roughness of boulder surfaces on the summit blockfield does not direr significantly from the roughness of bedrock surfaces downslope as far as the lower trimline. These unexpected results suggest that bedrock surfaces between the two trimlines were not glacially abraded during the Late Weichselian, so that the upper trimline is unlikely to represent the vertical limit of ice during either the Late Weichselian or a subsequent readvance. Preliminary results of 10 Be dating of surface quartz samples from above the lower trimline support the proposal that the site was not abraded during the last glaciation. The results can be interpreted in two ways: (1) The upper trimline represents the vertical limit of a pre-Late Weichselian advance. During the Late Weichselian the mountains were completely covered but surfaces down to the lower trimline were protected by cold-based ice. (2) The lower trimline marks the vertical limit of the Late Weichselian ice and the upper limit an older and more extensive glaciation. 相似文献
9.
Nunataks of the last ice sheet in northwest Scotland 总被引：1，自引：0，他引：1
DANNY McCARROLL COLIN K. BALLANTYNE ATLE NESJE SVEIN-OLAF DAHL 《Boreas: An International Journal of Quaternary Research》1995,24(4):305-323
High-level weathering limits separating ice-scoured topography from an upper zone of frost-weathered detritus were identified on 17 mountains in NW Scotland at altitudes of <600 m to< 900 m, and a further 6 peaks were found to support evidence of ice scouring to summit level. Weathering limits are most clearly defined on Torridon Sandstone, which is resistant to frost shattering, but can also be mapped on Cambrian Quartzite, Lewisian Gneiss and Moine Schist. Contrasts in degree of rock surface weathering above and below the weathering limits were evaluated using measurements of joint depth and rock surface hardness, and through X-ray diffraction analyses of clay mineral assemblages. The results indicate significantly more advanced rock and soil weathering above the weathering limits. Widespread persistence of gibbsite above the weathering limits suggests that they represent the upper limit of Late Devensian glacial erosion, and the regularity of the decline in weathering limit altitude along former flowlines eliminates the possibility that it represents a former thermal boundary between protective cold-based and erosive warm-based ice. The weathering limits are therefore interpreted as periglacial trimlines defining the maximum surface altitude of the last ice sheet around former nunataks. Calculated basal shear stresses of 50–78 kPa are consistent with this interpretation. The altitude of the trimlines implies that the former ice shed lay at 900–930 m in the Fannich Mountains and descended gently northwards, and that the ice surface descended NW from the ice shed to >500 m over the extreme NW tip of Scotland and to 700–730 m at the head of Little Loch Broom. 相似文献
10.
Eleven shallow cores display 315 m of the >700 m thick Lower and Middle Triasic successional of the Svalis Dome, a Salt diapir in the central south-western Barents Sea. The Svalis Dome was uplifted in the late Mesozoic. and Trisassic rocks suherop below Quaternary till around the Upper Palaeozoic core of the dome. Deposition of the Triassic succession took place in deep shelf to basinal environments below storm wave base. The succession is dated by macrofossils and palynomorphs and can be assigned to four formations. The basal beds of the shaly greenish grey Havert Formation (Griesbachian) occur above Permian bioclastic carbonate. The Klappmyss Formation (Smithian) in the lower part contains gravity flow sands deposited as submarine fans pussible triggered by tectonic movements along the adjacent ault zones overlian by silty claystones. An organic-rich dark shale unit is here formally defined as the Steinkobbe overlain by silty claystones. An organic-rich dark shale unit is here formally defined as the Steinkobbe Formation, and was deposited in a large bight by restricted water circulation. The Snadd Formation. on top, representes a marine shelf unit deposited in front of an emerging land area in the north-east. A minimum of six higher order transgressive-regressive sequences are recognized at the Svalis Dome and these are correlated with other Arctic areas. 相似文献