Late-Pleistocene and Holocene mountain permafrost geomorphology of Norway and Iceland.

The combined effect of glacial and periglacial processes on landscape evolution has recently been termed the ‘cryoconditioning’ of landscapes, and largely affect the Fennoscandian landmass. Further, the distribution of permafrost both temporally and spatially during and after the last glaciation affect the overall geomorphic expression. In this thesis the product of landscape evolution is investigated in terms of the geomorphic imprint of glacial and periglacial processes, where the interactions between glaciers and permafrost have been particularly focussed upon. Whereas the glacial variations over the Holocene are relatively well known the same is not the case for the permafrost distribution. As a starting point, inventories of landforms indicating present and former permafrost were compiled for mainland Norway and northern Iceland. The main findings from the inventories were (1) a low abundance of landforms in Norway and a high abundance of landforms in Iceland probably due to differences of bedrock competence, (2) an apparent change in processes leading to rock glacier formation occurred in mid-Holocene from a dry, periglacial regime characterizing early-Holocene to a humid, glacially-dominated regime in mid- to late-Holocene, and (3) warm and maritime permafrost regions are dominated by permafrost landforms formed by the influence of glaciers. For Iceland the occurrence of relict rock glaciers at sea level imply a possible earlier deglaciation or alternatively a less extensive Last Glacial Maximum (LGM) than commonly accepted. As a second step, modelling of permafrost variations over the Holocene was performed in depth and spatially, using a 1D heat flow model and a 2D equilibrium model (CryoGRID1.0). During the warm Holocene Thermal Maximum (HTM) the permafrost survived at high altitudes in southern Norway, whereas during the ‘Little Ice Age’ (LIA) the permafrost reached its greatest extent both in depth and spatially. From these results altitudinal zones of permafrost ages was suggested, analogous to age patterns for Arctic permafrost. From the Neoglaciation until present, the potential of glacier-permafrost interactions has been large. Thirdly, a case study of the currently very small glacier, or glacieret, Omnsbreen which formed and largely disappeared during the LIA was studied in terms of glacial geomorphic evidence for permafrost interaction. Modelled permafrost distribution for the LIA suggest permafrost presence in the Omnsbreen surroundings during its formation and decay, and the landform assemblage present at Omnsbreen is considered representative for mountain glaciers terminating into permafrost. Permafrost is currently only present sporadically in the Omnsbreen surroundings, and the glacier and permafrost underwent a parallel disintegration. The current geomorphic expression of Norway and northern Iceland is significantly affected by long-term interactions between the glacial, subglacial and ground thermal regimes

The influence of ground ice distribution on geomorphic dynamics since the Little Ice Age in proglacial areas of two cirque glacier systems

International audienceHolocene glaciers have contributed to an abundance of unstable sediments in mountainous environments. In permafrostenvironments, these sediments can contain ground ice and are subject to rapid geomorphic activity and evolution undercondition of a warming climate. To understand the influence of ground ice distribution on this activity since the Little Ice Age(LIA), we have investigated the Pierre Ronde and Rognes proglacial areas, two cirque glacier systems located in the periglacial beltof the Mont Blanc massif. For the first time, electrical resistivity tomography, temperature data loggers and differential global positioningsystems (dGPS) are combined with historical documents and glaciological data analysis to produce a complete study of evolutionin time and space of these small landsystems since the LIA. This approach allows to explain spatial heterogeneity of current internalstructure and dynamics. The studied sites are a complex assemblage of debris-covered glacier, ice-rich frozen debris and unfrozendebris. Ground ice distribution is related to former glacier thermal regime, isolating effect of debris cover, water supply to specificzones, and topography. In relation with this internal structure, present dynamics are dominated by rapid ice melt in the debriscoveredupper slopes, slow creep processes in marginal glacigenic rock glaciers, and weak, superficial reworking in deglaciatedmoraines. Since the LIA, geomorphic activity is mainly spatially restricted within the proglacial areas. Sediment exportation hasoccurred in a limited part of the former Rognes Glacier and through water pocket outburst flood and debris flows in Pierre Ronde.Both sites contributed little sediment supply to the downslope geomorphic system, rather by episodic events than by constant supply.In that way, during Holocene and even in a paraglacial context as the recent deglaciation, proglacial areas of cirque glaciers actmostly as sediment sinks, when active geomorphic processes are unable to evacuate sediment downslope, especially because ofthe slope angle weakness

Relict blockstreams at Insteheia, Valldalen-Tafjorden, southern Norway: Their nature and Schmidt-hammer exposure age

Two small blockstreams, the first such landforms to be recorded in the mountains of Scandinavia, are described from Insteheia, a col at 910 m asl on the watershed between Valldalen and Tafjorden (Møre og Romsdal), southern Norway. Both blockstreams display morphological and sedimentological characteristics indicative of boulder accumulations that have moved downslope by means of solifluction most probably under a permafrost climatic regime. These comprise boulder preferred orientation and dip patterns; inverse grading comprising surface boulders overlying successively finer, well-sorted cobble, pebble and finegrained (sand/silt dominated) sediment layers; imbrication, with the packing of small boulders behind larger boulders; and proximity to boulder-strewn hillslopes whose constituent boulders (organised into lobes and terraces) feed downslope into the blockstreams. Schmidt-hammer exposure-ages of 7.24 to 11.17 ka indicate that the blockstreams were last active during the Younger Dryas Stadial – Holocene transition (~9.5-11.2 ka). It is inferred that blockstream development began at ~18 ka, following the Last Glacial Maximum, and lasted for ~8 ka, and that since the blockstreams became inactive fine grained material has been progressively lost as a result of snowmelt runoff. The small areal extent and relatively recent age of the blockstreams contrast with larger-scale forms of considerably greater age in the Southern Hemisphere

Simulating the effect of subsurface drainage on the thermal regime and ground ice in blocky terrain in Norway

Ground temperatures in coarse, blocky deposits such as mountain blockfields and rock glaciers have long been observed to be lower in comparison with other (sub)surface material. One of the reasons for this negative temperature anomaly is the lower soil moisture content in blocky terrain, which decreases the duration of the zero curtain in autumn. Here we used the CryoGrid community model to simulate the effect of drainage on the ground thermal regime and ground ice in blocky terrain permafrost at two sites in Norway. The model set-up is based on a one-dimensional model domain and features a surface energy balance, heat conduction and advection, as well as a bucket water scheme with adjustable lateral drainage. We used three idealized subsurface stratigraphies, blocks only, blocks with sediment and sediment only, which can be either drained (i.e. with strong lateral subsurface drainage) or undrained (i.e. without drainage), resulting in six scenarios. The main difference between the three stratigraphies is their ability to retain water against drainage: while the blocks only stratigraphy can only hold small amounts of water, much more water is retained within the sediment phase of the two other stratigraphies, which critically modifies the freeze–thaw behaviour. The simulation results show markedly lower ground temperatures in the blocks only, drained scenario compared to other scenarios, with a negative thermal anomaly of up to 2.2 ∘C. For this scenario, the model can in particular simulate the time evolution of ground ice, with build-up during and after snowmelt and spring and gradual lowering of the ice table in the course of the summer season. The thermal anomaly increases with larger amounts of snowfall, showing that well-drained blocky deposits are less sensitive to insulation by snow than other soils. We simulate stable permafrost conditions at the location of a rock glacier in northern Norway with a mean annual ground surface temperature of 2.0–2.5 ∘C in the blocks only, drained simulations. Finally, transient simulations since 1951 at the rock glacier site (starting with permafrost conditions for all stratigraphies) showed a complete loss of perennial ground ice in the upper 5 m of the ground in the blocks with sediment, drained run; a 1.6 m lowering of the ground ice table in the sediment only, drained run; and only 0.1 m lowering in the blocks only, drained run. The interplay between the subsurface water–ice balance and ground freezing/thawing driven by heat conduction can at least partly explain the occurrence of permafrost in coarse blocky terrain below the elevational limit of permafrost in non-blocky sediments. It is thus important to consider the subsurface water–ice balance in blocky terrain in future efforts in permafrost distribution mapping in mountainous areas. Furthermore, an accurate prediction of the evolution of the ground ice table in a future climate can have implications for slope stability, as well as water resources in arid environments.</p

Schmidt-hammer exposure ages from periglacial patterned ground (sorted circles) in Jotunheimen, Norway, and their interpretative problems

© 2016 Swedish Society for Anthropology and Geography Periglacial patterned ground (sorted circles and polygons) along an altitudinal profile at Juvflya in central Jotunheimen, southern Norway, is investigated using Schmidt-hammer exposure-age dating (SHD). The patterned ground surfaces exhibit R-value distributions with platycurtic modes, broad plateaus, narrow tails, and a negative skew. Sample sites located between 1500 and 1925 m a.s.l. indicate a distinct altitudinal gradient of increasing mean R-values towards higher altitudes interpreted as a chronological function. An established regional SHD calibration curve for Jotunheimen yielded mean boulder exposure ages in the range 6910 ± 510 to 8240 ± 495 years ago. These SHD ages are indicative of the timing of patterned ground formation, representing minimum ages for active boulder upfreezing and maximum ages for the stabilization of boulders in the encircling gutters. Despite uncertainties associated with the calibration curve and the age distribution of the boulders, the early-Holocene age of the patterned ground surfaces, the apparent cessation of major activity during the Holocene Thermal Maximum (HTM) and continuing lack of late-Holocene activity clarify existing understanding of the process dynamics and palaeoclimatic significance of large-scale sorted patterned ground as an indicator of a permafrost environment. The interpretation of SHD ages from patterned ground surfaces remains challenging, however, owing to their diachronous nature, the potential for a complex history of formation, and the influence of local, non-climatic factors

Small rock-slope failures conditioned by Holocene permafrost degradation:a new approach and conceptual model based on Schmidt-hammer exposure-age dating, Jotunheimen, southern Norway

Rock-slope failures (RSFs) constitute significant natural hazards but the geophysical processes which control their timing are poorly understood. However, robust chronologies can provide valuable information on the environmental controls on RSF occurrence: information which can inform models of RSF activity in response to climatic forcing. This paper uses Schmidt-hammer exposure-age dating (SHD) of boulder deposits to construct a detailed regional Holocene chronology of the frequency and magnitude of small rock-slope failures (SRSFs) in Jotunheimen, Norway. By focusing on the depositional fans of SRSFs (≤ 103 m3), rather than on the corresponding features of massive RSFs (~108 m3), 92 single-event RSFs are targeted for chronology building. A weighted SHD age-frequency distribution and probability density function analysis indicate four centennial- to millennial-scale periods of enhanced SRSF frequency, with a dominant mode at ~4.5 ka. Using change detection and discreet Meyer wavelet analysis, in combination with existing permafrost depth models, we propose that enhanced SRSF activity was primarily controlled by permafrost degradation. Long-term relative change in permafrost depth provides a compelling explanation for the high-magnitude departures from the SRSF background rate and accounts for (i1) the timing of peak SRSF frequency, (2ii) the significant lag (~2.2 ka) between the Holocene Thermal Maximum and the SRSF frequency peak, and (3iii) the marked decline in frequency in the late-Holocene. This interpretation is supported by geomorphological evidence, as the spatial distribution of SRSFs is strongly correlated with the aspect-dependent lower altitudinal limit of mountain permafrost in cliff faces. Results are indicative of a causal relationship between episodes of relatively warm climate, permafrost degradation and the transition to a seasonal-freezing climatic regime. This study highlights permafrost degradation as a conditioning factor for cliff collapse, and hence the importance of paraperiglacial processes; a result with implications for slope instability in glacial and periglacial environments under global warming scenarios

Winter amplification of the European Little Ice Age cooling by the subpolar gyre

Climate reconstructions reveal a strong winter amplification of the cooling over central and northern continental Europe during the Little Ice Age period (LIA, here defined as c. 16th-18th centuries) via persistent, blocked atmospheric conditions. Although various potential drivers have been suggested to explain the LIA cooling, no coherent mechanism has yet been proposed for this seasonal contrast. Here we demonstrate that such exceptional wintertime conditions arose from sea ice expansion and reduced ocean heat losses in the Nordic and Barents seas, driven by a multicentennial reduction in the northward heat transport by the subpolar gyre (SPG). However, these anomalous oceanic conditions were largely decoupled from the European atmospheric variability in summer. Our novel dynamical explanation is derived from analysis of an ensemble of last millennium climate simulations, and is supported by reconstructions of European temperatures and atmospheric circulation variability and North Atlantic/Arctic paleoceanographic conditions. We conclude that SPG-related internal climate feedbacks were responsible for the winter amplification of the European LIA cooling. Thus, characterization of SPG dynamics is essential for understanding multicentennial variations of the seasonal cycle in the European/North Atlantic sector

Marine Harvest Group : Strategisk regnskapsanalyse og verdivurdering

Masteroppgave økonomi og administrasjon BE501 - Universitetet i Agder 2018The purpose of this thesis is to find Marine Harvest Groups equityandshare price as of 30.06.2018. We will use accounting data for the period 2011 to 2018 Q2 to carry out a fundamental-and the method of comparables analysis of the company. After relevant adjustments we ended up with a stock price of NOK 211,32. The priceindicates that Marine Harvestsvalue at the Oslo Stock Exchange of NOK 162,20 is undervalued. Therefore, we will recommend buying Marine Harvest stocks. To be able to conduct a fundamental valuation it has been necassary to obtain knowledge about thecompany and the industry. The information hasbeen gathered through a presentation of the company and the industry, followed by a strategic analysis of Marine Harvest. The strategic analysis we conducted were PESTEL, Porters five forces, Generic bulidningblocksofcompetitve advantage, SVIMA and SVI. The analysis gave us an overview of the external and internal affairs that affects the company. From the strategic analysis we uncovered that Marine Harvest are in posession of temporary strategic advanteges.The advantages areresources within research and development, in addition to having their own feed production. They also have some strategic disadvantages in the form of a weak brand name, low product differentiation and a lower cost efficiency than theircompetitors.The next step was to carry out a financial statement analysis, risk assesment and calculate the WACC. Further we used these calculations to forecast a financial statement for the future. The financial statement is based on our expecations for the future and thus uncertain. With the information we had gathered we conducted the fundamental valuation followed by a sensitivity analysis. From the sensitivity analysis it was obvious that Marine Harvests stock price was heavily effected by growth inoperating income, operating margin, the turnover rate of net operating assets and equity requirements. Then we conducted a method of comparables analysis.Acombination of thetwo methodswas used to establish a stock price and an appropriate trade strategy

Spatial predictions of pingo, ice-wedge polygon and rock glacier occurrence across the circumpolar permafrost region for recent and future periods

This dataset contains spatial predictions of the potential environmental spaces for pingos, ice-wedge polygons and rock glaciers across the Northern Hemisphere permafrost areas. The potential environmental spaces, i.e. conditions where climate, topography and soil properties are suitable for landform presence, were predicted with statistical ensemble modelling employing geospatial data on environmental conditions at 30 arc-second resolution (~1 km). In addition to the baseline period (1950-2000), the predictions are provided for 2041-2060 and 2061-2080 using climate-forcing scenarios (Representative Concentration Pathways 4.5 and 8.5). The resulting dataset consists of five spatial predictions for each landform in GeoTIFF format. The data provide new information on 1) the fine-scale spatial distribution of permafrost landforms in the Northern Hemisphere, 2) the potential future alterations in the environmental suitability for permafrost landforms due to climate change, and 3) the circumpolar distribution of various ground ice types, and can 4) facilitate efforts to inventory permafrost landforms in incompletely mapped areas