Arctic Station Dirigibile Italia

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OBJECTIVE The project will quantify slope landscape evolution during the Holocene following climate change, focusing on the effects of Late-glacial to Holocene versus Little Ice Age to present deglaciation at selected sites along the Kongsfjorden area (NW Spitsbergen, Svalbard Archipelago). One main aim is to test the conceptual model for paraglacial adjustment in permafrost region outlined by (Etzelmuller and Frauenfelder, 2009), focusing on timescales of rock slope modification, development of rock glaciers, and the stability of ice-cored moraines.rnThe results will provide a contribution to the contested question of long-term periglacial landscape evolution.rnPROJECT OUTLINErnRationale. The general equation for paraglacial sediment exhaustion suggested by (Ballantyne, 2002), was corrected for permafrost environments by introducing a ground temperature factor (Etzelmuller and Frauenfelder, 2009) so that the exhaustion rate coefficient increase due to  permafrost degradation, or decrease following permafrost aggradation. For ice-cored moraine terrain, for instance, this implies that ground ice melting may cause more rapid paraglacial response than otherwise expected, while frozen rock walls might impede landscape adjustment after deglaciation. We attempt to test this model.rn2. Approach. The slopes of the Kongsfjorden area have been developing since their respective time of deglaciation. Since the deglaciation history in this area is known quite well (Henriksen et al., 2014), one can use a space for time substitution to investigate landscape change as a function of time. Landscape change will be approached by considering a source-to-sink framework, and thus focusing on sites where either erosion or deposition (or both) can be quantified from the baseline of glacier retreat. In this framework, the slopes from the top to the base can be affected by different processes that may or may not create distinct landforms. To make the approach feasible, we focus on a limited number of settings. First, high altitude and lower slope gentle angled surfaces are subjected to active layer solifluction and frost creep, creating distinct creep landforms such as solifluction lobes and sheets and providing a slow but spatially quite continuous mass transfer of importance for long-term slope development (Berthling et al., 2002; Egholm et al., 2015). Warm summer and deep thaw, such as the 2015 summer on Svalbard, will trigger thaw of the transient layer and potentially increase creep rates, and such relationships could be successfully documented from analysis of SAR images from suitable time periods.rnSecond, rock walls are exposed to weathering and become the source of mass movements that build up talus slopes. Some talus slopes develop further into rock glaciers. Except where there is a valley-bottom glacier, both talus slopes and rock glaciers have a limited and in most cases assessable connectivity with other processes that redistribute sediments, providing a quantifiable sediment sink that can be converted to rock slope retreat rates e.g. (Berthling and Etzelmuller, 2007). Third, ice-cored moraines on slopes constitute a well-defined landform as well as a slope sediment source that can be depleted from mass movements and thermo-karst processes e.g. (Schomacker and Kjær, 2008). Although parts of this material may be exported to the marine system, the total loss of debris can be reasonable well assessed from the amount of erosion.rnFourth, fluvial channels on slopes are caused by erosion and provide effective export of fine grained materials and solutes; however coarse debris may be retained in alluvial fans and deltas providing again means to assess total sediment yield within the catchment. Slope and channel coupling, sediment characteristics and bedload transport capacity of the system determine if channels are eroded into the permafrost, and thus the long-term stability of the system and its functioning in a paraglacial setting.rnMethods.Overview mapping of slope systems of the Kongsfjorden area at different sites from the inner part of the fjord to the outer part (i.e. Brøggerhalvøya, Blomstrandøya, Ossian Sarsfjellet, Prins Karls Forland) from aerial photographs (see below) and field investigations.rnGeomorphological mapping will be carried out according to the methodology and general guidelines of the Geological Survey of Norway (NGU) in order to realize geomorphological maps coherent with ongoing work in the Longyearbyen area. Fieldwork and sample collecting will be carried out according to current regulations and requirements for Svalbard, NyÅlesund and protected areas.rnField analysis of selected slopes (i.e. detailed geomorphological mapping of surface-cover deposits, and glacial, periglacial, slope and fluvial landforms; geomechanical analysis; geomorphometric and geophysical investigations of sediment source and sink volumes (terrestrial laser scanner, ERT and GPR geophysical investigation), and related drainage systems (sediment budget delivery analysis, solute and stable particles migration, types and routes for surface’s transport of mineral particles, including hydrological modelling of river sediment transport).rnRemote analysis of the selected slopes (i.e. photogeology analysis (aerial photographs provided by Norsk Polarinstitutt, analysis on digital platforms), satellite remote sensing (interferometric analysis of SAR imagery), rock fall and debris 2D-3D numerical modelling).rnAnalysis. Data from the project will be used to assess the temporal evolution of the paraglacial sediment delivery component, and for developing conceptual models of geomorphological slope evolution (related to solifluction, rock walls, rock glaciers and moraines) in different lithological and geomorphological settings of the Kongsfjorden area. These results will be compared to results elsewhere on Svalbard (Hornsund area, Polish station) and Central Spitsbergen area (Rubensdotter et al., 2013), and parallel studies undertaken in the Antarctic region (Oliva and Ruiz?Fernández, 2015) Rachlewicz 1999, Zwoli?ski 2007). Further, we will utilize results from studies focusing on paraglacial adjustmens following deglaciation in the Alps. The effects on the onset of deep-seated gravitational slope deformation and slope instability processes were for instance recently assessed in the Italian Alps and in the Carpathians by means of geomorphic evidence and radiocarbon dating (Soldati et al., 2004; Borgatti and Soldati, 2010, Kotarba and D?ugosz 2010) while rapid mass movements involving large volumes of ice and rock occurred recently in the Alps (Fischer et al., 2013; Huggel, 2009). The results of the project and the conceptual models of slope evolution could further provide a useful contribution for the comprehension of potential geomorphological hazards in the Svalbard region and in paraglacial environments.

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Late-glacial and present landscape evolution following deglaciation in a climate-sensitive High Arctic region (SLOPES)