Hypotheses and observations on the origin of the landscape of southern Norway—A comment regarding the isostasy-climate-erosion hypothesis by Nielsen et al. 2008     

Karna Lidmar-Bergstrm  Johan M. Bonow 《Journal of Geodynamics》2009,48(2):95-100

  相似文献   

Distinction between the Storegga tsunami and the holocene marine transgression in coastal basin deposits of western Norway     

Stein Bondevik  John Inge Svendsen  Jan Mangerud 《第四纪科学杂志》1998,13(6):529-537

Many coastal lakes were inundated by both the Storegga tsunami (7000 ¹⁴C yr BP) and the mid-Holocene sea-level rise (the Tapes transgression) in western Norway. The tsunami eroded lake bottoms and deposited graded and/or massive beds of sand, rip-up clasts, and coarse plant material. By contrast, when the rising sea entered the lakes, it deposited only gyttja, silt and fine sand, without causing much erosion of the underlying lake sediments. Storegga tsunami deposits in some coastal lakes were interpreted previously as ordinary marine sediments from the Tapes transgression. Our reinterpretation of these deposits shows that the transgression maximum phase was reached after 6500 yr BP, more than 1000 yr later than previously inferred for the coast of Sunnmøre. The new data cannot be combined in a shoreline diagram without showing the 6000 yr BP and 7000 yr BP shorelines as slightly warped. © 1998 John Wiley & Sons, Ltd.  相似文献   

Magmatic evolution of the Løkken SSZ Ophiolite,Norwegian Caledonides: Relationships between anomalous lavas and high-level intrusions     

Tor Grenne 《Geological Journal》1989,24(4):251-274

The Lower Ordovician Løkken ophiolite fragment shows a tripartite subdivision of its thick volcanic sequence into: (1) an Upper Volcanic Member (UVM) of transitional MORB/IAT character, comprising basalts or, in a related, thrust-bounded sequence, a bimodal basalt-rhyolite assemblage; (2) a Middle Volcanic Member (MVM) derived from widely variable, generally MORB-related magmas; and (3) a Lower Volcanic Member (LVM) of N-type MORB basalts which locally passes into an underlying sheeted dyke complex. The UVM and LVM were fed from relatively deep-seated magma chambers, and lavas were erupted at moderate flow rates to form predominantly pillow lavas. The whole sequence is interpreted as having formed in a marginal basin setting. The MVM is characterized by abundant voluminous sheet basalts thought to have been erupted at high flow rates. The volcanites had their source, through extensive dyke swarms, in high-level magmas which intruded the sheeted dyke complex and parts of the LVM, possibly in a near-axial seamount setting. The magmas differentiated to form plagiogranitic melts, with a wide range of conjunctive, mafic to intermediate cumulates. This plutonic assemblage, possibly in crystal mush form, was subsequently intruded by new, mafic magma, leading partly to large-scale remelting or assimilation of cumulus phases. These processes are reflected in the MVM by common hybrid flows, as well as local intermediate lavas having the geochemical characteristics of cumulates, erupted during a period of intense faulting. Major tapping of the primary, mafic magma occurred toward the end of the period of MVM volcanism. A predominance of voluminous, apparently fluid, massive flows in the MVM is mainly ascribed to the shallow depth of magma reservoirs.  相似文献   

The Origin of the Proterozoic Bidjovagge Gold-Copper Deposit, Finnmark, Northern Norway, as Deduced from Rare Earth Element and Nd Isotopic Evidences on Calcites     

Feng–Jun NIE  Arne BJ&#;RLYKKE  Kjell S. NILSEN 《Resource Geology》1999,49(1):13-25

Abstract: The Bidjovagge gold-copper deposit, northern Norway occurs in the lower Proterozoic Kautokeino greenstone belt, and consists of ten ore bodies in albite felsite, graphite schist and meta-diabase sills, along with a series of syenodiorite dykes. Calcite is one of the most important gangue minerals occurring within the ore veins. The early primary calcite samples from A, C and D ore bodies (copper–rich) show almost flat chondrite-normalised REE curves, and slightly positive Eu anomalies. A Sm-Nd isotope age of 1858 ± 72 Ma (2ρ) has been given based on fifteen primary calcite samples. The Sm-Nd age of calcite is in well agreement with previously published U-Pb davidite age of 1885 ±18 Ma (2ρ) and Sm-Nd davidite age of 1886 ± 88 Ma (2ρ). All these isotopic age data indicate that the gold-copper mineralisation may occur during or slightly after the peak of the Svecokarelian orogeny. Two late primary calcite samples from C and D ore bodies have flat chondrite-normalised LREE curves, positive HREE curves, and negative Eu anomalies. In contrast, most of the early primary calcite samples from B ore body (gold–rich) show an overall negative chondrite-normalised REE slope and negative Eu anomalies. Sm-Nd data on seven primary calcite samples from the B ore body are relatively scattered, and gave an isochrone age of 1809 ± 150 Ma (2ρ), identical to the age of the calcite samples from A, C and D ore bodies. Two late primary calcite samples from the B ore body have almost flat chondrite-normalised REE slope and negative Eu anomalies. REE patterns and eNd (T) values of calcites suggest that the ore fluids for the calcites from the A, C and D ore bodies derived their metals from mafic igneous rocks (diabase sills). For the secondary calcites from the C ore body, their relative high initial Nd (T) values at 1858 Ma imply that much more radiogenic Nd-component were incorporated during calcite crystallisation when another ore fluid emplaced. Combined Nd isotope data and REE geochemical features suggest that the isotopically more evolved source such as albite felsite and syn-genetic high level syenodiorite dykes were probably metal source for these calcites in the B ore body. Three samples of secondary calcite from the B ore body, which obviously deviated from 1809 Ma isochron are easily explained as products of post-ore hydrothermal events.  相似文献   

A growth model that incorporates individual variability for the Norway lobster population (Nephrops norvegicus, L. 1758) from the bay of Biscay     

Verdoit  M.; Pelletier  D.; Talidec  C. 《ICES Journal of Marine Science》1999,56(5):734-745

  相似文献   

Spatial scale and habitat-dependent diversity patterns in nematode communities in three seepage related sites along the Norwegian Sea margin     

Saskia Van Gaever  Maarten Raes  Francesca Pasotti  & Ann Vanreusel 《Marine Ecology》2010,31(1):66-77

Assessing the relative contribution of local diversity to regional biodiversity may be the key to understanding large-scale and even global patterns in species diversity. Here, the contribution of habitat heterogeneity of cold seeps at three spatial scales [micro-scale (ms), macro-scale (10 to 100s of ms), and mega-scale (10 to 100s of km)] to the total nematode biodiversity (genus level) along the Norwegian continental margin is evaluated. Due to the development of higher resolution bathymetry and increased bottom sampling in recent years, continental margins, once regarded as monotonous landscapes, are now acknowledged to have a high degree of habitat complexity and diversity. By calculating the additive partitioning of gamma diversity in alpha and beta fractions, we examined to what extent habitat diversity of seep sites significantly increases the nematode genus composition and diversity at different spatial scales. Siboglinidae patches and control sediments yielded comparably high levels of nematode genus richness. They exhibited low turnover rates within and across the different seep sites. In contrast, the bacterial mats at Håkon Mosby Mud Volcano (HMMV) and the reduced sediments at the Nyegga pockmarks harboured genus-poor nematode communities with an equally high dominance of one or two species, which were different for each seep. Different habitats, in particular at the HMMV, contributed significantly to the seep nematode richness. This study demonstrates that the presence of distinct habitat types within multiple seep sites contributes to the high diversity of nematode communities inhabiting the seeps in the Norwegian deep sea.  相似文献   

Fecundity of the European lobster (Homarus gammarus) off southwestern Norway after stock enhancement: do cultured females produce as many eggs as wild females?     

Agnalt  Ann-Lisbeth 《ICES Journal of Marine Science》2008,65(2):164-170

  相似文献   

The effect of metamorphic fluid flow on the nucleation and growth of garnets from Troms, North Norway     

A. D. L. SKELTON 《Journal of Metamorphic Geology》1997,15(1):85-92

A spatial association is observed between the size distribution of garnet porphyroblasts and the size distribution of quartz veins in greenschist facies metapelites from Troms, North Norway. The size distribution of quartz veins reflects the flow regime of metamorphic fluids. The hypothesis that the flow regime of metamorphic fluids is also responsible for the size distribution of garnet crystals was tested by ascribing empirical acceleration parameters to the nucleation and growth rates of garnet crystals.
In regions where fluid flow was interpreted as pervasive', acceleration parameters for nucleation were high, whereas in regions where fluid flow was interpreted as channelled', acceleration parameters for growth were high. Accelerated crystal growth is further implied from the chemical zoning and crystal morphologies of garnets collected near discrete veins.
This spatial association may imply that fluid flow can be instrumental in controlling garnet crystallization. Fluid flow could affect garnet crystallization kinetics by facilitating thermal advection and/or mass transfer. In the study area, rhodochrosite (MnCO₃) veins provide evidence for mass transfer of Mn by fluid flow. An influx of Mn would expand the stability field of garnet to lower temperatures. The resulting thermal overstep could accelerate nucleation and/or growth of garnets.
The corollary of this study is that size distributions and chemical zoning of garnets, or other porphyroblast phases, can be used to study metamorphic fluid flow.  相似文献   

Climate change and the effect of temperature backlashes causing frost damage in Picea abies     

Anna Maria Jnsson  Maj-Lena Linderson  Ingrid Stjernquist  Peter Schlyter  Lars Brring 《Global and Planetary Change》2004,44(1-4):195

In boreal and nemoboreal forests, tree frost hardiness is modified in reaction to cues from day length and temperature. The dehardening processes in Norway spruce, Picea abies, could be estimated to start when the daily mean temperature is above 5 °C for 5 days. Bud burst will occur approximately after 120–170 degree-days above 5 °C, dependent on genetic differences among provenances. A reduced cold hardiness level during autumn and spring and an advanced onset of bud burst are expected impacts of projected future global warming. The aim of this study was to test if this will increase the risk for frost damage caused by temperature backlashes. This was tested for Sweden by comparing output from the Hadley Centre regional climate model, HadRM3H, for the period 1961–1990 with future IPCC scenario SRES A2 and B2 for 2070–2099. Different indices for calculating the susceptibility to frost damage were used to assess changes in frost damage risk. The indices were based on: (1) the start of dehardening; (2) the severity of the temperature backlash; (3) the timing of bud burst; and (4) the cold hardiness level. The start of dehardening and bud burst were calculated to occur earlier all over the country, which is in line with the overall warming in both climate change scenarios. The frequency of temperature backlashes that may cause frost damage was calculated to increase in the southern part, an effect that became gradually less pronounced towards the north. The different timing of the onset of dehardening mainly caused this systematic latitudinal pattern. In the south, it occurs early in the year when the seasonal temperature progression is slow and large temperature variations occur. In the north, dehardening will occur closer to the spring equinox when the temperature progression is faster.  相似文献