排序方式： 共有16条查询结果，搜索用时 15 毫秒
1.
Dinoflagellate cysts in Upper Quaternary sediments from southwestern Norway and potential correlations with the oceanic record 总被引：1，自引：0，他引：1
Twenty-two samples from two locations at the Foss-Eigeland clay and gravel pit, Jæren, southwestern Norway were analysed for dinoflagellate cysts. Cyst recovery was generally poor and cyst assemblages indicate a cold temperate to arctic glacimarine environment. The percentage composition of a total of 19 cyst species identified allowed the recognition of five assemblage zones. These are thought to reflect fluctuating minor climatic changes during an interstadial period preceding the last glacial advance in the region. Cyst assemblages from these supposedly Middle Weichselian sediments at Foss-Eigeland are similar to those found in the northern North Sea and the Norwegian Sea in probably similarly aged sediments. This suggests a potential for using dinoflagellate cysts to correlate land-based Quaternary sequences with the deep sea record. 相似文献
2.
3.
KNUT BJÖRLYKKE 《Sedimentology》1974,21(2):251-272
The mineralogy and geochemistry of clastic sediments in the 1000 m thick Lower Palaeozoic marine sequence of the Oslo Region is discussed on the basis of 200 chemical (XRF) and mineralogical (X-ray diffractometer) analyses. The composition of these sediments is considered to largely be a function of the relative supply from land of the continental shield (Baltic Shield) and from island are systems to the NW in the Trondheim Region. The relative abundance of chlorite and illite is discussed in light of recent knowledge about their distribution in modern oceans. Middle Cambrian to Lowermost Ordovician black shales contain only illite as the dominant clay mineral and have a high potassium content. These sediments are thought to be derived from land on the continental shield, which during this period probably had a low relief and a warm climate where chlorite is not stable. Chlorite is introduced first in the Arenigan (L. Ordovician) and this is interpreted as evidence for transport of clastic chlorite from a developing island arc system in the Trondheim Region to the west. The highest chlorite/illite ratio in the Middle and Upper Ordovician sediments of the Oslo Region corresponds to a Taconic orogenic phase. The content of clastic chlorite in the Lower Palaeozoic of the Oslo Region is thus shown to be a sensitive indicator of palaeoenvironment and tectonic evolution of the Caledonian geosyncline. This conclusion is also supported by a systematic increase in Mg, Fe, Ni, and Cr from Lower to Middle and Upper Ordovician beds. High Cr values exceeding 0–1 % Cr in the Middle/Upper Ordovician shales are due to small grains of clastic chromite resembling those in the serpentinites of the Trondheim Region. This also suggests transport from exposed island arcs onto the epicontinental shelf. 相似文献
4.
This article discusses how different climate policy instruments such as CO2 taxes and renewable energy subsidies affect the profitability of fossil-fuel production, given that a fixed global climate target shall be achieved in the long term. Within an intertemporal framework, the model analyses show that CO2 taxes reduce the short-term profitability to a greater extent than technology subsidies, since the competition from CO2-free energy sources does not become particularly noticeable until decades later. Due to, for example, the discounting of future revenues, most fossil-fuel producers prefer subsidies to their competitors rather than CO2 taxes. However, this conclusion does not apply to all producers. Oil producers outside OPEC lose the most on the subsidizing of CO2-free energy, while CO2 taxes only slightly reduce their profits. This is connected to OPEC's role in the oil market, as the cartel chooses to reduce its extraction significantly in the tax scenario. The results seem to be consistent with the observed behaviour of important players in the climate negotiations. 相似文献
5.
PETER EMIL KALAND KNUT KRZYWINSKI BJØRG STABELL 《Boreas: An International Journal of Quaternary Research》1984,13(2):243-258
In three different areas in western Norway, large errors are obtained in the radiocarbon dates from lacustrine sediments close to marine/lacustrine sediment boundaries. Differences occur between radiocar-bon and pollenanalytic dates and between dates at isolation/ingression contacts for lakes of the same altitude above the present sea level. Younger radiocarbon dates are also obtained below older ones in undisturbed sediments. When divergent dates occur, the radiocarbon dates always seem to be the youngest. Large differences are also found between NaOH soluble and insoluble fractions of the same sediment samples. Insoluble fractions generally yield younger dates than the soluble. Differences are not found, however, for dates younger than about 8,000 B.P. The dating errors are connected to periods with more oligotrophic conditions with isoetides. Their roots penetrate older sediments. Due to contamination of the organic part of the sediment from partly decomposed roots, some radiocarbon dates will be too young. The isoetide vegetation and the dating errors disappear when the lakes become dystrophic. 相似文献
6.
KNUT BJØRLYKKE 《Sedimentology》1966,6(4):343-345
The present paper describes the use of cellulose acetate replicas in the study of silicate rocks, particularly indurated sandstones. The procedure of Boardman and Utgaard (1964) for the reproduction of surface structures of polished limestone slabs for the study of Paleozoic Bryozoa, was modified and applied on silicate rocks using HF instead of formic acid as the etching agent. The polished slabs are etched with 40 % HF for 5–10 seconds and then washed, dried, wetted with acetone and gently pressed towards a mount of cellulose acetate. After drying, the specimen is quickly removed and an imprint is left on the acetate peel. By using thick (1.6 mm) cellulose acetate sheets no mounting on glass slides is needed, and the replica can be studied directly under the microscope or be used as a photographic negative. 相似文献
7.
CORNELIA WINGUTH DAVID M. MICKELSON EILIV LARSEN JESSICA R. DARTER CAROLYN A. MOELLER KNUT STALSBERG 《Boreas: An International Journal of Quaternary Research》2005,34(2):176-185
Winguth, C., Mickelson, D. M., Larsen, E., Darter, J. R., Moeller, C. A. & Stalsberg, K. 2005 (May): Thickness evolution of the Scandinavian Ice Sheet during the Late Weichselian in Nordfjord, western Norway: evidence from ice-flow modeling. Boreas , Vol. 34, pp. 176–185. Oslo. ISSN 0300–9483.
Results from experiments with a two-dimensional ice-flow model, applied along a west-east transect in western Norway, provide new constraints on the thickness evolution of the Scandinavian Ice Sheet throughout the Late Weichselian glaciation and deglaciation. Investigations took place along an E-W flowline of the former ice sheet at c. 62N, from the modern glacier Jostedalsbreen, through the Nordfjord, and across the continental shelf. A paleoclimate record from Kråkenes, which is located directly at the flowline, provides temperature and precipitation information for the time between 13 800 and 9200 cal. yr BP. LGM climate conditions for the study area are estimated from various GCM studies. The GISP2 δ18 O record has been tuned to the local data in order to provide a continuous temperature record as input for time-transgressive model runs. The results of all experiments suggest that the ice did not cover the highest mountain peaks in this area, and that nunataks persisted throughout the Late Weichselian glaciation. These findings are in contrast to results from many previous model studies and other ice-sheet reconstructions, but agree well with minimum thickness estimates from cosmogenic dating and with vertical ice limits inferred from lower block field boundaries and trimlines. 相似文献
Results from experiments with a two-dimensional ice-flow model, applied along a west-east transect in western Norway, provide new constraints on the thickness evolution of the Scandinavian Ice Sheet throughout the Late Weichselian glaciation and deglaciation. Investigations took place along an E-W flowline of the former ice sheet at c. 62N, from the modern glacier Jostedalsbreen, through the Nordfjord, and across the continental shelf. A paleoclimate record from Kråkenes, which is located directly at the flowline, provides temperature and precipitation information for the time between 13 800 and 9200 cal. yr BP. LGM climate conditions for the study area are estimated from various GCM studies. The GISP2 δ
8.
KNUT STALSBERG EILIV LARSEN DAG OTTESEN HANS PETTER SEJRUP 《Boreas: An International Journal of Quaternary Research》2003,32(1):149-166
Glacial lineations on a bank area and a coastal lowland, both bordering the Norwegian Channel, are studied with regard to morphology and distribution by means of side-scan sonar data, detailed digital maps and fieldwork. Their genesis and age are further elucidated through stratigraphic and sedimentologic information from excavations in one typical coast-parallel drumlin. Four excavated sections revealed four lithologic units: Prodeltaic glaciomarine sand, glaciofluvial gravel, glaciomarine diamicton and deformation till. After Middle Weichselian delta progradation, glaciomarine diamicton was deposited and later subglacially reworked by a northwards flowing glacier. The two upper diamictons form the main volume of the ridge, which is interpreted as a drumlin, and imply a reinterpretation of the Jæren part of the so-called Lista moraine. Preconsolidation of glaciomarine diamicton suggests a maximum ice thickness of 500 m during drumlin formation, indicating an ice surface slope of 1 m/km. The occurrence of sediments that provided low basal shear stresses, and the orientation of drumlins and megaflutes indicating ice confluence both point to high glacier flow velocities and suggest that an ice stream, rather than a slower moving part of the ice sheet, occupied the Norwegian Channel during the Late Weichselian maximum. Deformation till overlying, more or less, undeformed glaciomarine diamicton suggests that high glacier velocities during periods of low driving stresses were possible due to a subglacial deformable layer. 相似文献
9.
10.
KNUT KAISER ALEXANDRA HILGERS NORBERT SCHLAAK MICHA&#; JANKOWSKI PETER KÜHN SIXTEN BUSSEMER KRZYSZTOF PRZEGI&#;TKA 《Boreas: An International Journal of Quaternary Research》2009,38(3):591-609
Lateglacial buried soil horizons, which occur widely in sandy aeolian sequences of northern central Europe, were analysed in order to evaluate their regional pedostratigraphical and palaeoenvironmental potential. Data on stratigraphy, sedimentology, pedology, geochronology and palaeobotany from 29 palaeosol-bearing profiles at terrestrial sites are presented. Greyish Ahb and Eb horizons occur, as well as brownish Bwb and BwAhb horizons. They are 5–30 cm thick, showing similar pedological properties except colour, and they frequently bear charcoal typically from pine. Soil classification results in Albic Arenosols (Dystric) and Brunic Arenosols (Dystric) representing palaeosols of the Usselo and Finow types, respectively. Radiocarbon dating of the palaeosols reveals a dominance of Allerød ages followed by Younger Dryas and Preboreal ages. Most luminescence ages on overlying aeolian sands date into the Allerød–Younger Dryas interval. Mapping of all Usselo and Finow soil occurrences ( n =96) in northern central Europe known so far reveals a nearly closed Finow soil province between Usselo soil areas in NW Germany and central Poland, mainly situated in NE Germany. Most Usselo soils compiled contain charcoal, indicating widespread and repeated fires. Recent claims that the Usselo soil represents an event layer from rapid aeolian sedimentation caused by an extraterrestrial impact is rejected. Instead, both Usselo and Finow soils can be assumed to be pedostratigraphical marker horizons in northern central Europe and beyond. 相似文献