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11.
Paleoproterozoic evolution of Fennoscandia and Greenland   总被引:1,自引:0,他引:1  
The Paleoproterozoic evolution of Fennoscandia and Greenland can be divided into major rifting and orogenic stages. The Paleoproterozoic rifting of Fennoscandia started with 2.505-2.1 Ga, multiphase, southwest-prograding, intraplate rifting. Both Fennoscandia and Greenland experienced 2.1- 2.04 Ga drifting and separation of their Archean cratons by newly-formed oceans. The main Paleoproterozoic orogenic evolution of Fennoscandia resulted in the Lapland-Kola orogen (1.94-1.86 Ga) and the composite Svecofennian orogen (1.92-1.79 Ga). The Paleoproterozoic orogens in Greenland, from north to south, are the lnglefield mobile belt (1.95-1.92 Ga), the Rinkian .fold belt/Nagssugtoqidian orogen (1.88-1.83 Ga) and the Ketilidian orogen (c. 1.8 Ga). The Lapland-Kola orogen, Inglefield mobile belt and the Rinkian fold belt/Nagssugtoqidian orogen are continent-continent collision zones with limited formation of new Paleoproterozoic crust, whereas the Ketilidian orogen displays a convergent plate-tectonic system, without subsequent collision. The composite Svecofennian orogen is responsible for the main Paleoproterozoic crustal growth of Fennoscandia.  相似文献   
12.
The concentrations and composition profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, polybrominated diphenyl ethers and polychlorinated naphthalenes were determined in herring individuals collected from the commercial catches of the Bothnian Sea, northern Baltic. The median age of herring was 5.0 years and in the muscle the median toxic equivalent concentration of PCDD/Fs was 5.6 WHO(PCDD/F)-TEQ pg/g fresh weight (fw) and that of PCBs 2.7 WHO(PCB)-TEQ pg/g fw. The median sum concentration of PBDEs was 1.4 ng/g fw and that of PCNs 0.1 ng/g fw. Differences in age-dependent accumulation between the organohalogen groups and individual congeners were major. In the Bothnian Sea the content of organohalogen compounds in herring is obviously elevated due to the availability and large proportion of Mysis crustaceans in their diet. More intensive fishing could reduce the concentrations of organohalogens, including the abundant, accumulative and toxic 2,3,4,7,8-PeCDF congener in the Baltic herring catch.  相似文献   
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Northern Fennoscandia has experienced high-magnitude postglacial fault (PGF) events, yet the role of seismic tremors in subglacial deformations and meltwater discharge has remained obscure. We studied glacial geomorphology in Utsjoki, Finnish Lapland, an area characterized by the Utsjoki drumlin field fanning out north and northeast to the Younger Dryas End Moraines (YDEMs) in northern Norway. Paleolandslides were common on fells (i.e. mountains shaped by Pleistocene glaciations) and were formed in nunatak position evidencing fault-instability in app. 11,900 calibrated (cal) BP. An anastomosing network of eskers was found throughout Utsjoki, and was probably generated through short-lived sliding bed stages during the discharge of subglacial lake(s). The formation of networks is different from time-transgressive evolution of single-ridged eskers in arborescent (treelike) systems. The most probable triggering mechanism for the meltwater outburst(s) was an earthquake tremor(s) associated with fault-instability during the late and post-Younger Dryas (YD). The alignment of the esker network was inconsistent with parallel-to-iceflow streamlining and the eskers erode or superimpose drumlins. Hence the esker network post-dates the streamlining. In some cases, hummocky (Pulju) moraine was observed to coexist with esker network and peculiar ‘kettle’ and ‘liquefaction’ features. We propose that glacio-seismotectonic events contributed not only to landslides but were also the primary force behind subglacial evolution of esker networks and possibly even hummocky moraine.  相似文献   
15.
The monitoring programme of harmful substances in selected species in the Baltic Sea was started in 1979. In the present study, three-year averages of Zn, Cu, Cd and Pb in cod liver (Hg in cod muscle) and herring muscle are reported. The concentrations of heavy metals in cod show areal differences roughly in accordance with the concentrations of heavy metals in sea water. No significant differences between heavy metal concentrations in North Atlantic and Baltic Sea species were found, except for mercury, for which values in the Baltic Sea species are lower than in those from the North Atlantic.  相似文献   
16.
Jon G. Sutinen 《GeoJournal》1988,16(3):273-281
The establishment of Exclusive Economic Zones places enormous burdens on the resources of coastal states' enforcement agencies. An economic problem looms in that decisions must be made as to how much to allocate to enforcement relative to the expected benefits that can be derived. In this paper, the objective is to review the economic methods available for analysis of enforcement programs. A second objective is to report on the enforcement problems and prospects in three areas with important fishery resources.  相似文献   
17.
Rule interchange between information systems is expanding as new interoperable rule formats are emerging from research. However, existing spatial inference systems generally operate on locally stored data with an internal rule format. Consequently, their design offers little support or facilities for rule interchange. This article presents the requirements, components and design for a spatial inference system with rule interchange. Computational efficiency and overall functionality of the design are considered separately, with the latter demonstrated using encoded agricultural legislation and data. A spatial inference system with rule interchange is based on three primary components: rule representation, spatial functionality and data integration. Of these, the interoperable rule representation and data integration distinctly differ from existing spatial inference systems. The presented inference system combines a spatial superset of the W3C Rule Interchange Format (RIF) with full Open Geospatial Consortium simple feature access (OGC SFA) functionality and on-demand data integration utilising Resource Deception Framework (RDF). The design was found to be effective with a computational efficiency depending predominantly on the spatial operations. This design could be further adapted to implement spatial extensions for existing inference systems. Considerable benefits were also discovered when RIF was used as the native language for the inference engine, thereby removing the need for rule transformations and facilitating on-demand data integration with the GML.  相似文献   
18.
Chemometric modelling of soil element concentrations from diffuse visible and near-infrared (VSWIR, 350–2500 nm) reflectance spectroscopic measurements holds potential for soil element analyses. Research has demonstrated it particularly for organic agricultural soils, yet little is known about the VSWIR response of glacial tills. Soils with low organic matter content developed on unstratified glacial materials were studied at two geologically similar sites on the mafic metavolcanic rocks of the Lapland Greenstone belt in northern Finland. The till samples (n = 217) were composed primarily of quartz, plagioclase and amphibole having less than 3% of clinochlore, talc and illite. VSWIR spectra of mineral powder (<0.06 mm) samples were measured in the laboratory, and the spectral reflectance was regressed against partial elemental concentrations of till obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES) following hot aqua regia digestion. Partial least-squares regression (PLSR) analyses resulted in simultaneous prediction (R2 = 0.80–0.89) of several soil chemical elements such as Al (validation RMSE 1802 mg kg−1), Ba (5.85 mg kg−1), Co (0.86 mg kg−1), Cr (6.94 mg kg−1), Cu (2.54 mg kg−1), Fe (2088 mg kg−1), Mg (449.6 mg kg−1), Mn (0.82 mg kg−1), Ni (3.24 mg kg−1), V (4.88 mg kg−1), and Zn (0.80 mg kg−1). The electronic and vibrational molecular processes causing absorption might be responsible for accurate predictions of major elements such as Al, Fe and Mg. However, the concentrations of other major and trace elements could be predicted by the PLSR because they were cross-correlated to spectrally active soil elements or extraneous soil properties. Therefore, the applicability of the results is highly sample set specific. Further, the results show that in local scale studies at geologically fairly homogenous areas the limited spread of the data may restrict the use of the spectroscopic–chemometric approach. This paper demonstrates the capability of laboratory VSWIR spectroscopy for determining element concentrations of glacial tills. Further work should focus on overcoming the issues of sampling scale and understanding the causality for cross-correlation in quantification of the elements.  相似文献   
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This paper examines ways to reduce conflicts and improve the sustainability and value of marine recreational fisheries by fully integrating the recreational sector into the management of fisheries. One possibility involves a novel approach, here called angling management organizations (AMOs), which combines three of the more pervasive and promising trends in fishery management worldwide—management devolution, strengthened harvest rights, and co-management. AMOs are community-based organizations that are designed to conform to seven basic principles of integrated fishery management, which are described below. AMOs are loosely related to rights-based producer organizations in commercial fisheries, and are expected to strengthen resource stewardship, reduce enforcement and monitoring costs, alleviate management conflicts, and produce greater long-term net economic benefits in recreational fisheries. The other organizational structures considered here, including the management status quo, do not conform to all seven principles and are not expected to be as effective as AMOs.  相似文献   
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