Browsing by Author "Ewertowski, Marek"
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Item Changes of Arctic landscape due to human impact, north part of Billefjorden area, Svalbard.(Wydział Nauk Geograficznych i Geologicznych Uniwersytetu im. Adama Mickiewicza, 2010) Tomczyk, Aleksandra; Ewertowski, MarekThis study present indications of human impact on selected components of environment in the vicinity of Petunia Bay, Billefjorden, central Spitsbergen. The area is easy accessible and has low restriction of human activity so it is a need for monitoring of the human impact there. Three groups of objects were inventoried. Large-scale objects are attached to industrial impacts (mainly mining and transport of natural resources) – mines, warehouses, blocks. They are clustered around the west side of the bay – Pyramiden settlement. Medium-scale objects (mainly linear forms – path, tracks) were created by transport as well as scientifi c and tourist activity. Small-scale impacts (campsites, fi resites) were created mainly by scientists and tourists and scattered around whole study area. Industrial activity in this area took place between 1927 and 1998, but its tracks are persistent and hard to remove. Scientific and tourist movements also started at the beginning of the XX century, but nowadays the activities become more and more intensive.Item Depositional processes within the frontal icecored moraine system, Ragnar glacier, Svalbard.(Wydział Nauk Geograficznych i Geologicznych Uniwersytetu im. Adama Mickiewicza, 2010) Ewertowski, Marek; Kasprzak, Leszek; Szuman, Izabela; Tomczyk, Aleksandra M.The marginal zone of the Ragnar glacier has been divided into four zones: ice surface, proglacial lake, lateral moraine and frontal moraine complex. Detailed researches were carried out in the last one - frontal moraine complex consisting of three subzones: (1) outer moraine ridge, (2) culmination moraine ridge and (3) inner moraine plateau. The frontal moraine complex of the Ragnar glacier shows large variability of lithofacies and depositional processes. The aim of this study was to reconstruct the intensity and variability of depositional processes from early stage of the frontal ice-cored moraines creation till present situation. Debris fl ow processes, glaciofl uvial and glaciolacustrine sedimentation as well as aeolian activity and down- and backwasting are identifi ed as most important processes. Intensity of these processes has varied through the time. Presently the frontal ice-cored moraine complex of the Ragnar glacier is relatively stable, except few areas affected by the river or streams.Item Quantification of the ice-cored moraines' short-term dynamics in the high-Arctic glaciers Ebbabreen and Ragnarbreen, Petuniabukta, Svalbard(ELSEVIER, 2015-04-01) Ewertowski, Marek; Tomczyk, AleksandraExtensive ice-cored moraine complexes are common elements, marking the last advance of many Svalbard glaciers. Sediment gravity flows are among the most dynamic processes, transforming these landforms. The short-term (yearly and weekly) dynamics of mass-wasting processes were studied in a cm-scale using repetitive topographic scanning. We monitored several active sites on the forelands of two glaciers, Ebbabreen and Ragnarbreen, both of which are located near Petuniabukta at the northern end of Billefjorden in Spitsbergen. The surveys indicate high dynamic rates of landforms' transformation. The mean annual volume loss of sediments and dead-ice for the most active parts of the moraines was up to 1.8 m a− 1. However, most of the transformation occurred during summer, with the short-term values of mean elevation changes as high as − 104 mm day− 1. In comparison, the dynamics of the other (i.e. non-active) parts of the ice-cored moraines were much lower, namely, the mean annual lowering (attributed mainly to dead-ice downwasting) was up to 0.3 m a −1, whereas lowering during summer was up to 8 mm day− 1. Our results indicate that in the case of the studied glaciers, backwasting was much more effective than downwasting in terms of landscape transformation in the glacier forelands. However, despite the high activity of localised mass movement processes, the overall short-term dynamics of ice-cored moraines for the studied glaciers were relatively low. We suggest that as long as debris cover is sufficiently thick (thicker than the permafrost's active layer depths), the mass movement activity would occur only under specific topographic conditions and/or due to occurrence of external meltwater sources and slope undercutting. In other areas, ice-cored moraines remain a stable landsystem component in a yearly to decadal time-scale.Item Recent transformations in the high-Arctic glacier landsystem, Ragnarbreen, Svalbard(Wiley / © 2014 Swedish Society for Anthropology and Geography, 2014-08-28) Ewertowski, MarekRagnarbreen is a small glacier located in the central part of Spitsbergen Island (Svalbard archipelago) and fed by the larger ice mass of Mittag-Lefflerbreen. Glacier recession and landforms' development in the foreland of Ragnarbreen are quantified using time-series orthophotos and digital elevation models, which were generated based on aerial photographs from 1961 (black and white frame camera), 1990 (false infrared frame camera) and 2009 (colour digital camera), obtained from the Norsk Polar Institute. Receding from its maximum Little Ice Age extent, attained in the period 1900/1920–2013, the glacier margin retreated by 1658 m while the extent of the area of ice decreased by 26%. The glacier snout lost 135 million m3 of ice during the period 1961–2009, whereas landform changes (mainly due to dead-ice melting and debris flow activity) were more than twenty-five times lower, with the less than 5 million m3 of sediment and dead ice volume loss. In terms of landscape alteration between 1961 and 2009, the most important was the creation of a terminoglacial lake, which acted as a sedimentary trap and at the same time probably accelerated glacier retreat. The second most active component was the lateral moraines whose transformations were divided into four phases, with various magnitudes of debris flow and backwasting activity that changed with time. The end moraine complex was the most stable component, affected mainly by dead-ice downwasting and to a lesser extent by sporadic debris flows.