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A two-step climatic warming and oceanographic change during the Younger Dryas/Preboreal transition was registered by diatom, foraminiferal, mollusc, lithologic data and sediment accumulation rates in a high resolution sediment core from the Swedish west coast. An abrupt climatic warming in the surface water of the Kattegat occurred at c . 10 200 BP, resulting in a rapid increase in sea surface water temperatures. The attenuation of meltwater discharge into the Kattegat led to an increase in sea surface salinity. Consequently, the difference in salinity through the water column diminished. This change happened within less than 80 years. The warming of bottom water in the deeper parts of the region took place a few hundred years after the surface water warming. The climatic amelioration was recorded by increased meltwater discharge and a slight increase in abundance of relatively warm diatoms around 10 600 BP at the time of the recession of the Fennoscandian ice sheet. An increase in the number of arctic/subarctic benthic foraminifera shows that the bottom water temperature during this period was still relatively low.  相似文献   
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Late Weichselian glaciation history of the northern North Sea   总被引:8,自引:1,他引:8  
Based on new data from the Fladen, Sleipner and Troll areas, combined with earlier published results, a glaciation curve for the Late Weichselian in the northern North Sea is constructed. The youngest date on marine sedimentation prior to the late Weichselian maximum ice extent is 29.4 ka BP. At this time the North Sea and probably large parts of southern Norway were deglaciated (corresponding to the Alesund interstadial in western Norway). In a period between 29.4 and c. 22 ka BP, the northern North Sea experienced its maximum Weichselian glaciation with a coalescing British and Scandinavian ice sheet. The first recorded marine inundation is found in the Fladen area where marine sedimentation started close to 22 ka BP. After this the ice fronts receded both to the east and west. The North Sea Plateau, and possibly parts of the Norwegian Trench, were ice-free close to 19.0 ka, and after this a short readvance occurred in this area. This event is correlated with the advance recorded at Dimlington, Yorkshire, and the corresponding climatostratigraphic unit is denoted the Dimlington Stadial (18.5 ka to 15.1 ka). The Norwegian Trench was deglaciated at 15.1 ka in the Troll area. The data from the North Sea, together with the results from Andwa, northern Norway (Vorren et al . 1988; Møller et al . 1992), suggest that the maximum extent of the last glaciation along the NW-European seaboard from the British Isles to northern Norway was prior to c . 22 ka BP.  相似文献   
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The late Weichselian sequence in the northern part of the Norwegian Trench is composed of eight units. The two lowermost units are massive, firm to stiff diamictons, interpreted to have been deposited beneath ice-streams that in all likelihood reached the shelf edge. They are overlain by glaciomarine and normal-marine sediments deposited after 15000BP. The first phase of glacial retreat from the Norwegian Trench (15000–14800 BP) was very rapid and left a thin layer of proximal sediments on top of the tills. This was followed by a period with lower accumulation rates (14800–13600 BP), probably as a result of rapid source retreat and cold meltwater inhibiting dropstone fall-out. The end of this interval marks the change from ice-stream calving in cold water to melting on land. According to lithologic and isotopic data, the maximum rate of Fennoscan-dian ice-sheet disintegration took place around 12500 BP. The water temperatures declined significantly and rates of sedimentation and ice-rafting fell in association with the Younger Dryas period. The final retreat of the ice began as early as 10 500 BP, and the transition to normal-marine sedimentation is reflected by precipitation of iron oxide followed by pyrite, reduced sedimentation rates, and a change from terrigenous to biogenic sedimentation.  相似文献   
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Stray, Kristen Fredrik: Små og mellomstore industribedrifter i Oslo indre by. Problemer, konflikter og tiltak i byfornyelsen. Geografisk Tidsskrift 83: 42–48, May 1., 1983.

In 1977 the City Council of Oslo passed an act of city renewal. 18 renewal districts in the inner part of Oslo were chosen. These areas with houses and housing facilities of low quality consist of a mixture of dwellings and economic activities of industry and trade. This paper deals with the problems and conflicts one meets when bringing through a renewal programme of housing and environmental improvements that cause restrictions to future economic activities or force firms to move out.  相似文献   
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A new temperature reconstruction with decadal resolution, covering the last two millennia, is presented for the extratropical Northern Hemisphere (90–30°N), utilizing many palaeo‐temperature proxy records never previously included in any large‐scale temperature reconstruction. The amplitude of the reconstructed temperature variability on centennial time‐scales exceeds 0.6°C. This reconstruction is the first to show a distinct Roman Warm Period c. ad 1–300, reaching up to the 1961–1990 mean temperature level, followed by the Dark Age Cold Period c. ad 300–800. The Medieval Warm Period is seen c. ad 800–1300 and the Little Ice Age is clearly visible c. ad 1300–1900, followed by a rapid temperature increase in the twentieth century. The highest average temperatures in the reconstruction are encountered in the mid to late tenth century and the lowest in the late seventeenth century. Decadal mean temperatures seem to have reached or exceeded the 1961–1990 mean temperature level during substantial parts of the Roman Warm Period and the Medieval Warm Period. The temperature of the last two decades, however, is possibly higher than during any previous time in the past two millennia, although this is only seen in the instrumental temperature data and not in the multi‐proxy reconstruction itself. Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods, except for the period c. ad 300–800, despite significant differences in both data coverage and methodology.  相似文献   
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A Late Pleistocene sequence at Margreteberg, southwestern Sweden   总被引:1,自引:0,他引:1  
At Margreteberg, southwestern Sweden, a comple Pleistocene sequence has been stratigraphically investigated. Strata of clay, silt, sand, peat and solifluction layers are overlain by till-like sediments which are covered by sandy-clayey strata. By means of biostratigraphical analyses (foraminifera, olluscs, wood remains, pollen and diatoms), a reconstruction of the palaeoenvirnmental development has been obtained. Radiocarbon measurements and amiono acis ratios have been carried out in order to date the sediments. The foraminifera in the lowermost clay strata indicate Arctic or boreal-Arctic marine environment during the Late Saalian or Late Elsterian perods The δ18 Ovalues and molluscs also suggest that the clay was deposited in glaciomarine conditions. Amino acid ratios (D/L=0.25) of Hiatella in the clay imply an age between the Holsteinian and Eemian Interglacials. Teh peat layers contain a pollen flora. Prtedominated by Picea and Pinus, and are pollen analytically dated to the end of the Eemian interglacial. The solofluction sediments most probably were fromed during the first stage (s) of the Early weichselian and may include the initaial phase of the Brorup Interstadial (the Rodebaek interstadial). During this stage(s) aretic-Subarctic conditions previaled reflected by a pollen flora with a predominance of herbs and shrubs. Acidophilous and aerohpilous diatoms indicate oligotrophic shallow wate conditions in an Arctic environment, when almost no leaching of mineral solis occurred. The solofluction sediments also contain reworked interglacial (Eemian) pollen and brackish-Marine diatoms. Radiocarbon dating of the peat, wood and solofluction sediments yieded infinnite ages>40,000B.P.  相似文献   
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Proxy data are our only source of knowledge of temperature variability in the period prior to instrumental temperature measurements. Until recently, very few quantitative palaeotemperature records extended back a millennium or more, but the number is now increasing. Here, the first systematic survey is presented, with graphic representations, of most quantitative temperature proxy data records covering the last two millennia that have been published in the peer-reviewed literature. In total, 71 series are presented together with basic essential information on each record. This overview will hopefully assist future palaeoclimatic research by facilitating an orientation among available palaeotemperature records and thus reduce the risk of missing less well-known proxy series. The records show an amplitude between maximum and minimum temperatures during the past two millennia on centennial timescales ranging from c. 0.5 to 4°C and averaging c. 1.5–2°C for both high and low latitudes, although these variations are not always occurring synchronous. Both the Medieval Warm Period, the Little Ice Age and the 20th century warming are clearly visible in most records, whereas the Roman Warm Period and the Dark Age Cold Period are less clearly discernible.  相似文献   
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