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1.
The seasonal evolution of the hydrographic structure of the West Spitsbergen Current (WSC) above bottom depths from 300 m to 800 m is discussed based on a modern data set with high spatial resolution. The WSC appears to have a core with high temperature and salinity, linked to the topography in this depth interval, with a width on the order of 10 km. Strong cooling occurs in the autumn, reducing the heat content of the upper 200 m, but advected temperature and salinity maxima survive close to the surface in spring when air-sea exchange and vertical mixing is hampered by sea ice and meltwater.  相似文献   

2.
The narrow slope-confined warm core of the West Spitsbergen Current (WSC) is a major pathway for warm and saline Atlantic Water to enter the Arctic Ocean. Long-term mean northward cooling and freshening rates in the warm core of the WSC are calculated with error ranges, and heat loss estimates are derived. The observed combination of cooling and freshening is not consistent with a hypothesis of pure isopycnal offshore mixing, but rather suggests influence from diapycnal mixing connected, for example, to exchange with shelf waters.  相似文献   

3.
The intensity of sea-ice interaction in the Fram Strait is estimated from hydrographic data by use of three different methods. Preliminary results concerning fresh water formation rate are reported.  相似文献   

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A year ago the writer published in this journal1 an article giving some preliminary results of studies on the continental shelf off the coasts of Norway. In a general map, a system of supposed submarine fault lines was shown — fault lines along which the Scandinavian land-mass is believed to have been lifted up in fairly recent, in Tertiary-Quaternary times. The existence of such lines is indicated by the presence of longitudinal channels, separating the area of banks from that of the rocky land-mass (with the »skjærgård« — skerries — area as its outermost zone) and by the way in which many transverse submarine valleys are abruptly cut off towards the land, along lines lying in the continuation of the said longitudinal channels.

It was maintained that the transverse channels represent the outer, peripheral, remnants of old valleys, the inner parts of which cannot generally be traced any longer because of the uplift and  相似文献   

6.
The annually thawing active layer of permafrost is central to considerations of climate change consequences in arctic areas and interpretations of deep permafrost temperatures that constitute and exceptional archive of past climate change. Moreover, a sound understanding of the thermal regime of the active layer is of great interest, because all chemical, biological and physical processes are concentrated there. The author studied this layer by examining the soil physical properties and heat transfer processes that dictate soil temperatures for an arctic desert site in northwestern Spitsbergen. A wide array of soil physical properties based on field observations and laboratory measurements were defined. These include mineralogy, grain size distribution, local regolith thickness, porosity, density, typical soil moisture profile, heat capacity and thermal conductivity. Heat transfer processes were studied through modeling of soil temperatures. The heat transfer model accounted for much of the observed soil thermal regime. It was found that thermal conduction, phase change of soil water at 0°C, and changes in unfrozen water content are the primary thermal processes that explain the observed soil temperatues in this field site. Melt-water infiltration, which is often overlooked in the energy budget, causes abrupt warming events and delivers considerable energy to the soil in late spring. An increase in frequency or magnitude of infiltration events could mimic simple spring time surface warming. Advection of ground water and soil internal evaporation were found to be generally unimportant at the site studied.  相似文献   

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常恩予  张敏 《地理科学进展》2022,41(8):1516-1529
随着现代社会空间和个人流动性水平的持续提升以及流动模式的日益复杂化,社会科学与空间科学领域对流动性的关注也持续升温。“流动转向”以来,西方流动性研究和交通地理学研究经历了激烈的碰撞,逐步展开了广泛深入的对话,推进了双方的互动发展和研究创新。而现有国内交通地理学对流动性的研究相对滞后,且跨学科的互利对话尚未有效开展。因而论文重点关注西方新流动性研究与交通地理学的对话交流与研究进展,通过梳理二者在流动性实践和意义、流动性不平等、信息通信技术与流动性3个共同议题下的探索,总结对国内交通地理学流动性研究的启示,并结合中国地理学相关研究现状以及社会发展与技术革新带来的流动性加剧状况,提出面向日常流动性的研究展望。中国流动性研究应进一步拓展流动性的多元内涵,丰富研究主体和尺度,辩证思考流动性价值,嵌入社会技术情境,并探索多元研究方法创新。  相似文献   

9.
The species composition and biomass of material collected in the summers 1981 and 1983 from 69 stations in the Hornsund fiord were analysed. 48 macroalgal taxa were found: 13 green algae, 18 brown algae and 17 red algae. 19 of these taxa were not reported from the nearby Isfjorden.
The overall biomass for the littoral zone varied from 0 to 216gnT2 formalin d.w., although in J of samples the biomass was between 20 and 80 gm_z. The dominant species were Fucus distichus, Acrosiphonia duriusada and Pilayella littoralis.
Using cluster analysis, an attempt was made to delimit regions with a characteristic species composition. The results obtained, however, do not permit this in the littoral zone of the Hornsund fiord.  相似文献   

10.
Palynological investigations of 16 sections from Spitsbergen, Svalbard, covering the uppermost Carboniferous, Permian and lowermost Triassic succession have been carried out. Because of general poor preservation and barrenness of the majority of the samples, it was not possible to establish a formal zonation for the Permian succession. The study resulted, however, in the recognition of three Permian palynological assemblages, restricted downwards by a Carboniferous assemblage and upwards by an earliest Triassic (Griesbachian) assemblage. The dating of these assemblages is based on palynological correlation with similar palynofloras elsewhere in the present Arctic region as well as dating by marine faunas, which in general give better stratigraphic resolution. The Permian assemblages recognised include (1) the Vittatina assemblage of late Gzhelian to early Asselian age recorded in the lower parts of the Tyrrellfjellet Member (Nordenskioldbreen Formation), (2) the Hamiapollenites tractiferinus assemblage of late Asselian to Artinskian age recorded in the upper parts of the Tyrrellfjellet Member and in the Gipshuken Formation and (3) the youngest Permian Kraeuselisporiles assemblage of late Artinskian to earliest Tatarian age recorded in the Kapp Starostin Formation.  相似文献   

11.
Seven samples from the Limestone and Boulder Conglomerate Members of the Bulltinden Formation have yielded poorly preserved conodonts. On tentative identifications Periodon aculeatus Hadding and Prioniodus cf. P. alobatus Bergstrom at the base of the formation suggest an Ordovician lower Caradoc, or older age. This confirms that the Vcstgotabrcen Formation unconformably beneath underwent high-pressure mctamorphism during the Taconic and/or Finmarkian phases of the Caledonian orogeny. The conodonts show affinity to the North Atlantic Province suggesting a deeper water marine depositional environment. Conodont colour alteration indices of five indicate that the Bulltinden Formation was heated to temperatures in excess of 300°C, probably during the middle-upper Silurian main Caledonian uplift event.  相似文献   

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The Siktefjcllet Group of late Silurian or early Devonian age. consisting of the Lilljeborgfjellet Conglomerate and the overlying Siktefjcllet Sandstone, is generally accepted as the oldest part of the Old Red Sandstone in Spitsbergen. Most of the clasts of the conglomerate are only slightly rounded and consist of lithologies typical for the underlying basement. A minor component of quartz porphyry clasts is present; these are well-rounded, indicating a longer transport. The provenance of the quartz porphyry clasts is discussed in relation to the known outcrops of quartz porphyry in Svalbard, one occurring in the neighbourhood of the conglomerate, the other ones far away. The quartz porphyry in close proximity is younger than the Lilljeborgfjellet Conglomerate and therefore not a possible source rock. A close petrographic and geochemical comparison with the quartz porphyries at three localities in Nordaustlandet (150-200 km in easterly direction and of probable Grenvillian age) is presented showing many similarities, but enough differences to question their interrelationship. The porphyries of the Hornsund area (300 km in southerly direction and also of probable Grenvillian age) are found to be chemically and pctrographically distinctly different from the Lilljeborgfjellet clast porphyry. Metarhyolite reported from the Planclfjclla and Har-kerbreen Groups in Ny Fricsland are not comparable with the clast porphyry. As no unquestionable source rock among the quartz porphyries is known in outcrop, the possibility of a hidden or completely eroded parent rock is considered.  相似文献   

14.
Kongsfjorden and Krossfjorden are two ice-proximal fjords on the western coast of Spitsbergen which have been surveyed using multibeam bathymetry, sub-bottom profiling and gravity coring. Central and outer Kongsfjorden is dominated by a 30 km2 outcrop of bedrock, with a thin (<10m) sediment cover. The bedrock displays a relict sub-glacial, ice-scoured topography produced during the glacial re-advances of the Weichselian (20 Ky BP) and again during the last major Holocene re-advance of the Little Ice Age (550-200 yrs BP). Drumlins and glacial flutes are common across the floor of Kongsfjorden, with lengths of 1.5-2.5 km and widths of <100 m, rising up to 10 m in water depths of <100 m. This topography is smoothed by bottom currents from the wind-driven forcing of surface waters. The flow is counter-clockwise, matching boundary layer movement under the influence of Coriolis force. Both fjords are characterized by a variable acoustic character, based on sub-bottom profile data. The deepest basins are dominated by parallel, well-laminated reflectors and an irregular-transparent acoustic character indicating the presence of Holocene-age fine-grained sediments up to 30 m thick. A parallel, irregular-transparent acoustic character with waveform morphology in inner Kongsfjorden is interpreted as moraines, originating from the 1948 and 1869 surges of Kronebreen glacier. Mass-flows are common on the flanks of topographic highs as acoustically chaotic-transparent lensoid and wedge-shaped reflectors. The sediments of outer and central Kongsfjorden are characterized by bioturbated, gas-rich homogeneous muds interpreted as being the result of the settling of fine-grained sediment and particulate suspensions.  相似文献   

15.
Tertiary and Quaternary deposits outcrop in the coastal cliff of Balanusviken at Sarsbukta in Vest-Spitsbergen. The Tertiary deposits appear by their foraminifera to belong to the Middle to Upper Oligocene. The Quaternary deposits consist of an upper part of Late Pleistocene to Holocene age, and a lower part which had previously been considered Middle Weichselian of age. Its foraminiferal assemblages suggest a higher age (Late Saalian, Eemian?). This lower part of the Quaternary deposits is related to a series of raised beaches with an upper limit at SO m above present day sea level. They were probably formed during the Eemian, and have not been distorted by later glaciation. The present study is based on sediment samples collected from the coastal cliff of Balanusviken, and particularly from that of Balanuspynten, Sarsbukta, Spitsbergen, during the summer expedition of Norsk Polarinstitutt in 19Sø.  相似文献   

16.
The development and age of the present geomorphology and superficial material of the Coloradofjella plateau, Spitsbergen, have been investigated through field surveying and laboratory sediment analyses. The focus was specifically on the role of glacial erosion and periglacial processes. The summit plain is deeply incised with large V-shaped valleys. Extensive networks of ice wedge polygons indicate that the fine-grained regolith is at least a few metres thick. An abundance of coarse-grained gabbroid erratics, clearly derived from sources further to the east, are distributed over parts of the summit plain. A vertical-walled dolerite dyke protruding up to 4 m above the adjacent surface shows no sign of glacial erosion. Our findings confirm that the present bedrock geomorphology and regolith in the summit plain survived at least the Late Weichselian glaciation. This is best explained by the ice sheet having been cold-based throughout its existence on the summit plain. Cold-based conditions imply that permafrost survived the last glacial cover. Based on the geomorphic evidence and estimates of Late Cenozoic erosion, we suggest that the present summit plains roughly represent the remains of a preglacial surface.  相似文献   

17.
Above the marine limit in Gangdalen, Nordenskiold Land, a 20 m thick sequence of unconsolidated sediments occurs. On the top of striated bedrock it is composed of a 2m thick till bed, 15m gravel interpreted to be deposited as a sandur, and another till bed on the top. A solifluction deposit is capping the section. Fabric analyses and erratics in the two tills indicate a similar development in glacial transport directions during the two glaciations, starting with a local glaciation which subsequently turns into a larger glaciation centred over the eastern part of Svalbard. Co-existence of different ice domes over Spitsbergen is suggested. The sandur was deposited during an ice free period with a sea-level 40–80 m higher than at present. The section is undated.  相似文献   

18.
The distribution of vascular plants within four sample areas on a deflation surface on a set of raised beach ridges near Kapp Linné. Spitsbergen, is described. The vegetation cover and distribution of the different species are related to the wind pattern and microtopography. Details of the distribution and growth characteristics of Dryas octopetala, Saxifraga oppositifolia , and Silene acaulis in relation to each other, and to the wind and microtopography are discussed.  相似文献   

19.
Pyroclastic material of a rhyolite type is present in some thin layers in the upper part of the De Geerdalen Z Formation in the Sassenfjorden area. This is the first evidence of late Triassic (Norian Rhaetian) volcanic activity in Svalbard.  相似文献   

20.
Traces of former glaciation were studied on Erdmannflya and Bohemanflya. Both peninsulas were probably completely covered by glaciers during the Late Weichselian and the final dcglaciation took place around years BP. Esmarkbreen readvanced shortly after 9,500 BP, probably a local and shortlasting event. Raised beaches occur to about 60 m above sea level, and date back to about 10,000 BP. Initial land emergence was rapid, about 3m/100 years. It seems to have been followed by a marine transgression between 8,500 and 7,500 BP, which resulted in a large and distinct beach bridge and marine abrasion cliffs about 10-12 m above present sea level. Mytilus edulis lived in the area between at least 9.000 and 5,000 BP. Five thousand years ago relative sea level probably stood 3-4 m higher than today. Relative sea level has remained close to present during the last centuries. Different positions of glacier fronts in this century have also been mapped.  相似文献   

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