Character and origin of variably deformed granitoids in central southern Sweden: implications from geochemistry and Nd isotopes     

Karin Appelquist  Linus Brander  ke Johansson  Ulf Bertil Andersson  David Cornell 《Geological Journal》2011,46(6):597-618

We present major and trace element data for eighteen 1.71–1.66 Ga granitoid samples, and Sm–Nd whole‐rock isotope data for eleven of these samples, in a transect across the border between the Transscandinavian Igneous Belt (TIB) and the Eastern Segment in central southern Sweden. The geochemistry of the granitoids varies from alkalic to alkali‐calcic and peraluminous in the east to predominantly calc‐alkaline and metaluminous in the west. Rocks in the west also have lower SiO₂ contents. Trace element signatures favour formation in an active continental margin setting. Nd isotope data are completely overlapping along the transect and initial ε_Nd values are mildly depleted in the range +0.3 to +2.6. The combined data suggest that the magmas were derived mainly from juvenile, pre‐existing crust, increasingly mafic and less alkaline towards the west. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Towards Better WMS Maps Through the Use of the Styled Layer Descriptor and Cartographic Conflict Resolution for Linear Features     

Ionuţ Iosifescu Enescu  Nadia H. Panchaud  Magnus Heitzler  Cristina M. Iosifescu Enescu  Lorenz Hurni 《The Cartographic journal》2013,50(2):125-136

Abstract

Mercator depicted Croatia on several general maps. In accordance with the level of geographical knowledge, map scales and technical possibilities of the time, Mercator provided a relatively detailed depiction of basic geographical features on these maps. His interest in mapping Croatia was probably motivated by the fact that the Venetian Republic, the Habsburg Monarchy and the Ottoman Empire had fought over this area in the sixteenth century, contributing to the fragmentation of the medieval Croatian State, while at the same time facilitating economic, religious, linguistic, artistic and scientific communication between Central, South East and Mediterranean Europe. Mercator paid special attention to toponyms that enabled geographical objects to be identified and the decoding of cartographic contents. Research into Mercator’s maps has shown that geographical names, among other things, clearly indicate the sources of spatial data that he used. Additionally, geographical names on Mercator’s maps are significant indicators of the linguistic and cultural contacts that were particularly prominent in border areas, for example, along the eastern Adriatic coast, or the courses of the Danube, Sava and Drava.  相似文献   

Effects of hysteresis,rainfall dynamics,and temporal resolution of rainfall input data in solute transport modelling in uncropped soil     

Magnus Persson  Alan Saifadeen 《水文科学杂志》2013,58(5):982-990

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Groundwater contamination risks from conservative point source pollutants in a future climate     

Magnus Persson  Tarek Selim  Jonas Olsson 《水文科学杂志》2013,58(13):1659-1671

ABSTRACT

The groundwater contamination risk in future climates was investigated at three locations in Sweden. Solute transport penetration depths were simulated using the HYDRUS-1D model using historical data and an ensemble of climate projections including two global climate models (GCMs), three emission scenarios and one regional climate model. Most projections indicated increasing precipitation and evapotranspiration until mid-century with a further increase at end-century. Results showed both increasing and decreasing groundwater contamination risks depending on emission scenario and GCM. Generally, the groundwater contamination risk is likely to be unchanged until mid-century, but higher at the end of the century. Soil and site specific relationships between Δ(P – PET) (i.e. change in the difference between precipitation, P, and potential evapotranspiration, PET) and changes in solute transport depths were determined. Using this, changes in solute transport depths for other climate projections can be assessed.  相似文献   

Elemental and isotopic carbon and nitrogen records of organic matter accumulation in a Holocene permafrost peat sequence in the East European Russian Arctic   总被引：1，自引：0，他引：1  

Rina Argelia Andersson  Philip Meyers  Edward Hornibrook  Peter Kuhry  Carl‐Magnus Mörth 《第四纪科学杂志》2012,27(6):545-552

A peat deposit from the East European Russian Arctic, spanning nearly 10 000 years, was investigated to study soil organic matter degradation using analyses of bulk elemental and stable isotopic compositions and plant macrofossil remains. The peat accumulated initially in a wet fen that was transformed into a peat plateau bog following aggradation of permafrost in the late Holocene (～2500 cal a BP). Total organic carbon and total nitrogen (N) concentrations are higher in the fen peat than in the moss‐dominated bog peat layers. Layers in the sequence that have lower concentrations of total hydrogen (H) are associated with degraded vascular plant residues. C/N and H/C atomic ratios indicate better preservation of organic matter in peat material dominated by bryophytes as opposed to vascular plants. The presence of permafrost in the peat plateau stage and water‐saturated conditions at the bottom of the fen stage appear to lead to better preservation of organic plant material. δ¹⁵N values suggest N isotopic fractionation was driven primarily by microbial decomposition whereas differences in δ¹³C values appear to reflect mainly changes in plant assemblages. Positive shifts in both δ¹⁵N and δ¹³C values coincide with a local change to drier conditions as a result of the onset of permafrost and frost heave of the peat surface. This pattern suggests that permafrost aggradation not only resulted in changes in vegetation but also aerated the underlying fen peat, which enhanced microbial denitrification, causing the observed ¹⁵N‐enrichment. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Evolution of In Situ Rock Mass Damage Induced by Mechanical–Thermal Loading     

Hengxing Lan  C. D. Martin  J. C. Andersson 《Rock Mechanics and Rock Engineering》2013,46(1):153-168

To understand and predict the in situ brittle rock mass damage process induced by a coupled thermo-mechanical loading, the knowledge of rock mass yielding strength, scaling relationship between laboratory and in situ and microstructure characterization is required. Difficulties have been recognized due to the seldom availability of in situ experiment and appropriate numerical methodologies. The Äspö Pillar Stability Experiment was used to monitor the evolution of rock mass damage in a pillar of rock separating two 1.75-m diameter vertical boreholes. The loading of the pillar was controlled using the in situ stresses, excavation geometry, and locally increasing the rock temperature. The induced loading resulted in a complex discontinuum process that involved fracture initiation, propagation, interaction and buckling, all dominated by a tensile mechanism. Tracking this damage process was carried out in two steps. Initially, a three-dimensional numerical model was used to generate the stresses from the excavation geometry and thermal loading. The plane strain stresses, at selected locations where detailed displacement monitoring was available, were then used to track the evolution of damage caused by these induced stresses. The grain-based discrete element modeling approach described in Lan et al. (2010), which captures the grain scale heterogeneity of the rock, was used to establish the extent of damage. Good agreement was found between the predicted and measured temperatures and displacements. The grain-based model provided new insights into the progressive failure process.  相似文献   

Arctic Ocean manganese contents and sediment colour cycles   总被引：5，自引：0，他引：5  

Ludvig Löwemark  Martin Jakobsson  Magnus Mörth  & Jan Backman 《Polar research》2008,27(2):105-113

Cyclical variations in colour and manganese content in sediments from the central Arctic Ocean have been interpreted to represent climatically controlled changes in the input of Mn from the Siberian hinterland, and/or variations in the intermediate and deep water ventilation of the Arctic basins, although a diagenetic origin has not been excluded. A reinvestigation of core 96/12-1pc using an Itrax X-ray fluoresence (XRF) core scanner confirms that these colour cycles are indeed controlled by variations in Mn content, although changes in the source region of the sediment may override the Mn colour signal in certain intervals. The prominent Mn cycles show no correspondence to any of the other measured elements. This decoupling of Mn and the bulk chemistry of the sediment is taken to indicate that the cycles observed are caused by variations in water column ventilation and riverine input, rather than variations in sediment source or diagenesis. We therefore conclude that the Mn maxima do represent warm phases with increased ventilation and/or riverine input, and that they therefore could be used for chronostratigraphic correlation between cores from the central Arctic Ocean, where traditional isotope stratigraphy is difficult or impossible to establish because of the lack of calcareous microfossils.  相似文献   

Waves and instabilities in dissipative rotating superfluid neutron stars     

T. Sidery  N. Andersson  G. L. Comer 《Monthly notices of the Royal Astronomical Society》2008,385(1):335-348

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On the design and selection of polychlorinated biphenyls for use in biological test systems     

M. Tysklind  P. L. Andersson  B. Van Bavel 《Marine environmental research》1998,46(1-5)

The polychlorinated biphenyls (PCBs) consist of a large number of individual congeners with varying degree of chlorination and possible substitution patterns. No single congener can be used as a representative congener for the whole class of compounds. Multivariate chemical characterisation (principal component analysis) in combination with factorial design provide tools by which small sets of structurally representative congeners can be determined. These tools are suggested to be used in the design of biological experiments in order to introduce systematic structural variation in the congeners to be tested and to make it possible to construct quantitative structure-activity relationships (QSARs). A QSAR based on bioaccumulation factors (BAFs) in fish for 20 systematically selected PCBs made it possible to predict BAFs for all 134 non-tested tetra-through hepta-chlorinated congeners. The use of these systematic and balanced sets of congeners in the experimental protocol will provide increased knowledge of the environmental behaviour of the PCBs.  相似文献   

Directional interpolation of multicomponent data          下载免费PDF全文

Fredrik Andersson  Adriana Citlali Ramírez  Torgeir Wiik  Viktor V. Nikitin 《Geophysical Prospecting》2017,65(5):1246-1263

A method for interpolation of multicomponent streamer data based on using the local directionality structure is presented. The derivative components are used to estimate a vector field that locally describes the direction with the least variability. Given this vector field, the interpolation can be phrased in terms of the solution of a partial differential equation that describes how energy is transported between regions of missing data. The approach can be efficiently implemented using readily available routines for computer graphics. The method is robust to noise in the measurements and particularly towards high levels of low‐frequent noise that is present in the derivative components of the multicomponent streamer data.  相似文献