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1.
The Nordic geological surveys: Geology for society in practice 总被引:1,自引:0,他引:1
Morten Smelror Andreas AhlstrФm Lena Ekelund Jens Morten Hansen Keijo Nenonen Anette K. Mortensen 《《幕》》2008,31(1):193-200
Since the mid-nineteenth century., when the first of the Nordic Geological Surveys were established, they have generated a substantial amount of information on the Earth's crust, its natural resources, its processes, and on the geological history of Nordic areas. The collective mission of the geological surveys is to carry out "Geology for Society", by doing research and providing services, and by making geological information and data easily accessible to all the varied end users in industry, government agencies, government institutes, public administrations, technical offices, academia and research institutes, as well as for private individuals. The present paper gives a brief overview of a few, selected, research areas and projects currently undertaken by the Nordic geological surveys. These serve as practical examples of how the Nordic geological surveys address important societal problems and challenges that require geological input for their solution. 相似文献
2.
Interannual variability in Nordic seas primary production 总被引:1,自引:0,他引:1
3.
Identification of Danish North Sea trawl fisheries 总被引:1,自引:3,他引:1
4.
5.
Lars Chresten Lund-Hansen Morten Pejrup Jens Valeur Anders Jensen 《Estuarine, Coastal and Shelf Science》1994,38(6)
Gross sedimentation rates (GSR) have been measured using sediment traps placed at nine different levels above the bed (0·3, 0·5, 0·8, 1·0, 2·0, 4·0, 6·0, 8·0 and 10·0 m). The sediment traps were deployed for 1·25 years and recovered 28 times during the study period. Low average GSR values of 5·5 g m-2 day-1 were obtained at 10·0 m, and high average GSR values of 114·8 g m-2 day-1 were obtained at 0·3 m. An expression for the eddy diffusion coefficient of suspended particulate matter (Ks), based on the measured GSR is given. The expression has been used for modelling of Ks at the different trap levels above the bed. High values (≈42 cm2 s-1) of Ks were obtained at the upper traps, whereas low values (≈2 cm2 s-1) were obtained near the bed. Comparison between level of turbulent energy in terms of shear stress at the boundaries of the water column, i.e. from the wind and the bed flow, showed that wind energy exceeded that of the bed flow by a factor 16. At 5·0 m Ks was positively correlated (r=0·66) to the eddy diffusion coefficient of momentum (Km) derived from the wind energy transfer to the water, giving an average β of 0·5 for Ks =βKm. The density difference between surface and bottom waters has been designated a parameter of stratification, and is discussed in relation to variations of Ks and Km . 相似文献
6.
Donald E. Canfield Claus A. Olesen Raymond P. Cox 《Geochimica et cosmochimica acta》2006,70(3):548-561
A synthesis of previous results, which we dub the “standard model,” provides a prediction as to how isotope fractionation during sulfate reduction should respond to physiological variables such as specific rate of sulfate reduction and environmental variables such as substrate availability and temperature. The standard model suggests that isotope fractionation should decrease with increasing specific rates of sulfate reduction (rate per cell). Furthermore, the standard model predicts that low fractionations should be found at both high and low temperatures whereas the highest fractionations should be found in the intermediate temperature range. These fractionation trends are controlled, as a function of temperature, by the balance between the transfer rates of sulfate into and out of the cell and the exchange between the sulfur pools internal to the organism. We test this standard model by conducting experiments on the growth physiology and isotope fractionation, as a function of temperature, by the sulfate-reducing bacterium Desulfovibrio desulfuricans (DSMZ 642). Our results contrast with the “standard model” by showing a positive correlation between specific rates of sulfate reduction and fractionation. Also by contrast with the standard model, we found the highest fractionations at low and high temperatures and the lowest fractionations in the intermediate temperature range. We develop a fractionation model which can be used to explain both our results as well as the results of the “standard model.” Differences in fractionation with temperature relate to differences in the specific temperature response of internal enzyme kinetics as well as the exchange rates of sulfate in and out of the cell. It is expected that the kinetics of these processes will show strain-specific differences. 相似文献
7.
Summary Crust-derived xenoliths hosted by Miocene basaltic diatremes in the Hyblean Plateau (south-eastern Sicily, Italy) provide
new information regarding the nature of a portion of the central Mediterranean lower crust. These xenoliths can be divided
into three groups: gabbros (plagioclase + clinopyroxene + Fe–Ti oxides ± apatite ± amphibole ± Fe-rich green spinel), diorites
(An-poor plagioclase, clinopyroxene ± Fe–Ti oxides ± orthopyroxene) and mafic granulites (plagioclase + clinopyroxene + green
spinel ± orthopyroxene ± Fe–Ti oxides). Gabbros form the main subject of this paper. They represent cumulates whose igneous
texture has been locally obliterated by metamorphic recrystallization and shearing. They were permeated by Fe–Ti-rich melts
related to tholeiitic-type fractional crystallisation. Incompatible element ratios (Zr/Nb = 5–26; Y/Nb = 1.4–11) indicate
that these cumulate gabbros derived from MORB liquids. Late-stage and hydrothermal fluids caused diverse, sometimes important,
metasomatic trasformations. Petrographic and geochemical comparison with gabbroids from well-known geodynamic settings show
that the Hyblean lower crustal xenoliths were probably formed in an oceanic or oceanic-continent transition environment. 相似文献
8.
T-matrix approach to shale acoustics 总被引:2,自引:0,他引:2
Morten Jakobsen John A. Hudson Tor Arne Johansen 《Geophysical Journal International》2003,154(2):533-558
9.
10.
High‐resolution stratigraphy of Scandinavian coastal archaeological settlements: the case of Håkonshella,W Norway 下载免费PDF全文
Arnald Puy Andrea L. Balbo Camilla Zinsli Morten Ramstad 《Boreas: An International Journal of Quaternary Research》2016,45(3):508-520
The stratigraphy of Scandinavian open‐air archaeological settlements is usually characterized as homogeneous, highly enriched in decomposing organic matter and poor in biogenic carbonates such as shells or bones. As a result, stratigraphies are often difficult to read in the field and settlement sequences may pass unnoticed by archaeologists. Here we show how the integration of bulk analyses, soil micromorphology, X‐ray fluorescence (XRF) core scanning and multivariate statistics can help in overcoming such limitations. We use the case study of Håkonshella 8, a Mesolithic hunter‐fisher‐gatherer settlement located in Bergen (W Norway). Fluctuations in the organic matter content, geochemical proxies (mainly P, Ga, Ti and the Si/Al ratio) and redoximorphic features highlight four cycles of site occupation and abandonment in an otherwise massive anthropogenic deposit. Following these settlement sequences, the site was covered by colluvium from nearby slopes over which a waterlogged soil formed. The approach used in Håkonshella has the potential to improve our capacity to interpret organically enriched anthropic deposits formed in coastal Scandinavia and in similar climatic regions. 相似文献