Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 14
items per page: 25 50 75
Sort by:

Abstract

This paper presents the results of geomorphological investigations in the area of Ebba Glacier. A granulometric characteristic is presented of some types of deposits localised both within the glacier and in its forefiels. Some complexes of glacial forms were distinguished, on the basis of which an attempt was made to establish the chronology of events responsible for the development of Ebba Valley. Their preliminary analysis permitted the hypothesis of the Wiirm glaciation of the valley and of the four — fold advancement of Holocene glaciers to be set.
Go to article

Abstract

In Northwestern and Central Spitsbergen geomorphological and botanical data were collected on slope deposits associated with infrequent meteorological events. In hillslope debris flows triggered by heavy rainfall, compact volumes of debris range from 1 to 600 m3 . Recurrence intervals of major episodes are tentatively estimated from lichenometry at 80 to 500 years. Such debris flows are widespread in Spitsbergen and induce conspicuous geomorphological effects. Nevertheless, typical levees and lobes are small-sized because of the thinness of permafrost and they rarely survive more than one century. In contrast, catastrophic slush avalanches mobilize 1300 to 7000 m3 of rock debris every 500 years, forming long boulder tongues and fans. Such accumulations can been observed in much more restricted sites. In Central Spitsbergen at least three generations of slush avalanche deposits have been identified and lichenometry suggests that such boulder tongues survive for at least 2000 years. So the geomorphic impact of sporadic slush avalanches appears much more important than the effects of recurrent spring snow avalanches which do not generate original and long-lasting landforms. Botanical studies show that investigations of saxicolous lichen communities allow more reliable chronological reconstructions than observations of phanerogamic and bryophytic vegetation cover. Rhizocarpon diameters are partly interpreted from growth curves from Baffin Island and North Alaska. The results will be refined when a curve is published for Spitsbergen. Nevertheless, recurrence intervals proposed here seem to be consistent and are fruitfully compared with previous evaluations from Swedish Lappland and Colorado.
Go to article

Abstract

The paper deals with dynamics of present morphologic processes and cover deposits of nival and subnival stages in the area to the north of the Hornsund Fiord. Qualitative and quantitative parameters of the processes are described on the basis of direct measurements and radiocarbon datings. A particular attention was paid to the action of frost and gravitational processes in the specific morphoclimatic conditions of a nival landscape stage. The cover deposits are described from the point of view of their origin and physico-chemical properties. The age of the covers is defined on the ground of radiocarbon datings of fossil plants found at the nunataks for the first time in 1973. These datings enabled to distinguish the development phases of the morphogenetic processes during Late Holocene.
Go to article

Abstract

A structure of recent morainic sediments, mainly of gravel — boulder fraction (15—60 mm) was studied in the extremely marginal part of the Werenskiold Glacier. The data were collected within three environments of glacial deposition i.e. supraglacial of dead glacial ice and layer of relegation ice adhering to the glacier bottom and subglacial ones. A distinct textural individuality is typical for supraglacial deposits. Arrangement and orientation of boulders coming from the basal part of a glacier as well as from the morainic subglacial sediment deposited under the active ice show many similarities. But in both latter zones as well as certain differentiation was found to be caused by morphology of the older bedrock, changes during a subglacial deposition and preliminary epigenetic changes that occur in the conditions of a subglacial regelation before a stabilization of a passive zone of subglacial permafrost.
Go to article

Abstract

On the basis of observations and topographic surveys carried out mainly in the northern part of Linnedalen on Spitsbergen, geological structure of the valley was described and determination of the forms of relief by the means of lithology was demonstrated. The relief of the valley was characterized with particular regard to periglacial processes. A geomorphological map of the northern part of Linnédalen was made and a part of a cataloque of polygonal and structural soils was prepared.
Go to article

Abstract

Complex analysis ofgeomorphological glacial processes in forefields of retreating glaciers in the southern Bellsund region was undertaken. Field studies and archival cartographic materials indicate continued glacial retreat, at least since the turn of the 19th and 20th centuries. Its average present rate of about 20 m/y is rather high and no moraine ridges are formed, except for the fluted moraines. Forefields of large glaciers are characterized by typical relief and sediments of frontal deglaciation only. Intensity and extent of glacial forefield remodelling depends mainly on activity ablation waters. At present glaciofluvial erosion predominates.
Go to article

Abstract

Studies over talus cones in nothwestern Wedel Jarlsberg Land enable to define main parameters of these forms, their morphogenetic features and longitudinal profiles. Three zones of occurrence of talus cones have been distinguished, dependent on microlimatic influence of glaciers. Zone A (below 150 m a.s.l.) is not influenced by glaciers. Zone В (from 150 to 350 m a.s.l.) is influenced by glacier snouts. Zone С (over 350 m a.s.l.) is under influence of firn fields. Most intensive development of talus cones in the studied area occurred during the Little Ice Age.
Go to article

Abstract

Results of geological interpretation of air photos from selected parts of southern Spitsbergen are presented. Quaternary and some older landforms and deposits distinguished during the photointerpretation are described on the basis of their discrimination features, as well as origin and spatial realtions. On this ground a code for interpretation of relief elements in polar areas was prepared. A geological interpretation of air photos completed by absolute datings of different deposits enabled to connect studied landforms with the Late Quaternary main glacial episodes. Sea and glacier extents in the northwestern Sörkapp Land, from the Wedel Jarlsberg Land Glaciation (Saale) to the Little Ice Age (Holocene) are presented.
Go to article

Abstract

The present paper contains the results of geomorphological investigations carried out by the author during the llnd Polar Expedition of the Scientific Society of the Students of the Department of Geography and Regional Studies, Warsaw University, to the northwest part of Nordenskiöld Land (West Spitsbergen) in the summer of 1980. The present elaboration discusses the glacial forms and deposits which arose during previous stays of the glacier on this area. Particular attention was paid to the disposition of erratics, which permitted the determination of the directions of the transgression of the young Quaternary glaciations.
Go to article

Abstract

Geomorphological research based on geomorphological mapping seeks to identify the origins and age of forms as well as to describe the process that created or transformed a particular form. One of the most important aspects of this study is the morphometry and morphology of the landscape. This also applies to the submarine areas, and issues related to marine geomorphometry. Bathymetric data used in this study were obtained from the measurements of the Norwegian Hydrographic Service and measurements conducted by the authors. Its main goal was: to determine the bathymetry of the Recherchefjorden (Bellsund, Svalbard), establish morphometric parameters for the analysis of the morphology of the bottom. The boundaries of zones, related to the specific character of bottom geomorphology linked with geological structure, tectonics and, in particular, the impact of glacial system, was delineated. The sets of landforms (areas) were distinguished based on the morphometric analysis resulting from the determined parameters: slopes, its aspects, curvatures and Bathymetric Position Index. Basically, this areas are concentrated in two zones: the main Recherchefjorden and its surroundings. The delimitation also takes into account the origins and location of theme in relation to the glacial systems. On this basis, moraine areas were distinguished. They are linked with the Holocene advances of two glaciers, Renardbeen and Recherchebreen, mainly during the Little Ice Age. They constitute boundary zones between areas with different morphometric parameters: outer fjord and inner fjord. Moreover, taking into account geology and terrestrial geomorphology it was possible to describe paraglacial processes in this area.
Go to article

Abstract

Twelve glaciers, representing various types, were investigated between 2000 and 2005, in a region adjacent to the northern reaches of Billefjorden, central Spitsbergen ( Svalbard ). On the basis of measurements taken using reference points, DGPS and GPS systems, analyses of aerial photographs and satellite images, geomorphological indicators and archival data their rates of deglaciation following the “Little Ice Age” (LIA) maximum were calculated variously on centennial, decadal and annual time scales. As most Svalbard glaciers have debris-covered snouts, a clean ice margin was measured in the absence of debris-free ice front. The retreat rates for both types of ice fronts were very similar. All studied glaciers have been retreating since the termination of the Little Ice Age at the end of 19th century. The fastest retreat rate was observed in the case of the Nordenskiöldbreen tidewater glacier (mean average linear retreat rate 35 m a-1). For land-terminating glaciers the rates were in range of 5 to 15 m a-1. Presumably owing to climate warming, most of the glacier retreat rates have increased several fold in recent decades. The secondary factors influencing the retreat rates have been identified as: water depth at the grounding line in the case of tidewater glaciers, surging history, altitude, shape and aspect of glacier margin, and bedrock relief. The retreat rates are similar to glaciers from other parts of Spitsbergen . Analyses of available data on glacier retreat rates in Svalbard have allowed us to distinguish four major types: very dynamic, surging tidewater glaciers with post-LIA retreat rates of between 100 and 220 m a-1, other tidewater glaciers receding of a rate of 15 to 70 m a-1, land terminating valley polythermal glaciers with an average retreat of 10 to 20 m a-1 and small, usually cold, glaciers with the retreat rates below 10 m a-1.
Go to article

Abstract

DC resistivity soundings and geomorphological surveys have been carried out in the marginal zones and adjacent outwash plains of two glaciers in central Spitsbergen, Norwegian Arctic: Ebbabreen and Hörbyebreen. The study has revealed complex relationships between landforms, buried glacier ice and permafrost. From this work it is possible to distinguish between moraine ridges which are ice-cored and those which are not. The latter occur in areas which have possibly been affected by glacier surge. The active layer thickness was found to be 0.4 to 2.5 m for diamicton deposits (moraines) and 0.3 to 1.6 m in outwash glacifluvial sediments. The sediment infill thickness in valleys was determined to be as much as 20 m, thereby demonstrating that sandurs have important role in sediment storage in a glacial system. Typical resistivity values for sediment types in both the active layer and in permafrost were also determined.
Go to article

This page uses 'cookies'. Learn more