| 1. |
- Adell, Anna, et al.
(author)
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Open-access portal with hindcast wave data for Skåne and Halland
- 2021
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In: Vatten: tidskrift för vattenvård /Journal of Water Management and research. - 0042-2886. ; 77:2, s. 81-90
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Journal article (other academic/artistic)abstract
- Wave climate data for the Swedish provinces Skane and Halland, were hindcast using SWAN, a third-generation spectral wave model. The 40-year wave dataset, from 1979 to 2019, is made available through an open-access data portal (https://gis.sgi.se/vagmodell/). The wave data has a three-hour resolution and includes significant wave height, peak wave period, and wave direction. The wave model domain encompasses the Baltic Sea, Öresund, Kattegat, and Skagerrak. Along the coast of Skane and Halland, the spatial resolution of the computational nodes, from which data can be extracted in the portal, is 250 m. In the offshore areas, the resolution of the computational grid is coarser. The simulated significant wave height was validated against observations from 25 wave gauges, operating intermittently during the simulation period. The coefficient of determination, R2, for these comparisons ranged from 0.46 to 0.93 for the different stations. For 15 wave gauges, R2 values for the comparisons exceeded 0.80. The wave model will continuously be updated and developed.
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| 2. |
- Andersen, J. L., et al.
(author)
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Pleistocene Evolution of a Scandinavian Plateau Landscape
- 2018
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In: Journal of Geophysical Research - Earth Surface. - 2169-9003 .- 2169-9011. ; 123:12, s. 3370-3387
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Journal article (peer-reviewed)abstract
- The origins and Pleistocene evolution of plateau landscapes along passive continental margins of the North Atlantic have been debated for more than a century. A key question in this debate concerns whether glacial and periglacial surface processes have substantially eroded plateau areas during late Cenozoic climatic cooling or whether the plateaus have mainly been protected from erosion by cold-based and largely nonerosive ice sheets. Here we investigate the Pleistocene evolution of a prominent plateau landscape in Reinheimen National Park, southern Norway. We estimate erosion rates across the plateau via inverse modeling of 141 new cosmogenic Be-10 and Al-26 measurements in regolith profiles and bedrock. We combine these results with sedimentological analyses of the regolith. In the vicinity of Reinheimen's regolith-covered summits, the combination of uniformly slow erosion (<10m/Myr) and near-parabolic slope geometry suggests long-term equilibrium with the presently active periglacial mass-wasting processes. Outside summit areas, erosion is faster (up to >50m/Myr), possibly due to episodic glacial erosion. Despite some indications of chemical alteration, such as grusic saprolite and small amounts of secondary minerals, the fine regolith comprises low clay/silt ratios and is dominated by primary minerals with no sign of dissolution. Together with our modeled erosion rates, this indicates that the regolith cover formed, and continues to develop, during the cold climate of the Late Pleistocene. Plain Language Summary Plateaus dissected by steep-sided valleys and fjords are common landscape elements within the mountains bordering the North Atlantic. Most of these plateaus have likely experienced millions of years of near-freezing temperatures and were repeatedly covered by ice sheets during recent glacial periods. Yet the imprint of cold-climate erosion processes on the plateau landscape evolution remains poorly understood. Here we investigate the Pleistocene evolution of an extensive Scandinavian plateau landscape in Reinheimen National Park, southern Norway. We measure cosmogenic nuclides within the surficial layers of rock and sediment on the plateau. The concentration of these cosmogenic nuclides reflects the erosion of the plateau landscape and thereby the impact of recent cold-climate surface processes. We find that erosion has influenced the plateaus within the latest glacial cycles. In the vicinity of the highest, sediment-clad summits, the plateau shape is determined by processes related to freezing and thawing of rocks and sediment, while the influence of erosion by glaciers and streams increases further downslope.
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| 3. |
- Fritzon, Ruben, 1977-, et al.
(author)
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Evaluating geochemical evidence of earthquake periodicity, Sparta Fault, Southern Greece
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Other publication (other academic/artistic)abstract
- Determining prehistoric earthquake periodicity and magnitudes is important for risk assessments in seismically active areas. We evaluate a geochemical method, which has previously been used to identify prehistoric slips on normal fault scarps through an analysis of variations in the concentration of rare earth elements and Y (REE-Y) along vertical transects. Our study object is the Sparta Fault, a normal fault in southern Greece, developed in limestone and previously documented, and dated using 36Cl, to have been last active 464 BC. From geochemical analyses of 39 fault rock samples, we conclude that REE-Y concentrations correlate strongly with the abundance of quartz and possibly other heterogeneities in the fault scarp. Because the sampled fault rock is a protocataclasite, formed at depth, variations in the abundance of quartz are not associated with prehistoric movements along the fault. We therefore conclude that geochemical evidence does not provide a reliable paleoseismic proxy for fault movement. We also present data indicating a co-variation between quartz and 36Cl concentrations, which we suggest requires a re-examination of this widely used application of the cosmogenic nuclide surface exposure dating method.
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| 4. |
- Glasser, Neil F., et al.
(author)
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Cosmogenic nuclide exposure ages for moraines in the Lago San Martin Valley, Argentina
- 2011
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In: Quaternary Research. - : Cambridge University Press (CUP). - 0033-5894 .- 1096-0287. ; 75:3, s. 636-646
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Journal article (peer-reviewed)abstract
- At several times during the Quaternary, a major eastward-flowing outlet glacier of the former Patagonian Ice Sheet occupied the Lago San Martin Valley in Argentina (49 degrees S, 72 degrees W). We present a glacial chronology for the valley based on geomorphological mapping and cosmogenic nuclide ((10)Be) exposure ages (n = 10) of boulders on moraines and lake shorelines. There are five prominent moraine belts in the Lago San Martin Valley, associated with extensive sandar (glaciofluvial outwash plains) and former lake shorelines. Cosmogenic nuclide exposure ages for boulders on these moraines indicate that they formed at 14.3 +/- 1.7 ka, 22.4 +/- 2.3 ka, 34.4 +/- 3.4 ka to 37.6 +/- 3.4 ka (and possibly 60 +/- 3.5 ka), and 99 +/- 11 ka (1 sigma). These dated glacier advances differ from published chronologies from the Lago San Martin Valley based on (14)C age determinations from organic sediments and molluscs in meltwater channels directly in front of moraines or in kettleholes within end moraine ridges. The moraine boulder ages also point to possible pre-LGM glacial advances during the last glacial cycle and a key observation from our data is that the LGM glaciers were probably less extensive in the Lago San Martin Valley than previously thought.
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| 5. |
- Goodfellow, Bradley, et al.
(author)
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Beach morphodynamics in a strong-wind bay: a low energy environment?
- 2005
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In: Marine Geology. ; 214, s. 101-116
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Journal article (peer-reviewed)abstract
- The morphodynamic behaviour of a multibarred beach in a fetch-limited, strong-wind bay (Seaford Beach, SE Australia) was examined during both high and low-energy conditions, and considered in the context of a definition of low-energy provided in the literature. Measurements of nearshore waves, currents, and morphology revealed a bimodal behaviour. Under initial low-energy conditions, the beach exhibited a “low tide terrace” state, and waves and currents were of very low magnitude. During subsequent high-energy conditions, the beach demonstrated dynamic behaviour through the formation of a transitional “transverse bar and rip – rhythmic bar and beach,” and migration of the middle bar, with the morphology remaining in an arrested high-energy state during intervening low-energy periods. Although broadly conforming to the morphodynamic model, the beach did exhibit some distinct characteristics attributable to its fetch-limited location; limited progression through the morphodynamic model, and the importance of wind direction and magnitude in governing morphodynamic behaviour. Furthermore, rip currents were not significant in driving beach change through intermediate states. The presence of infragravity energy in the storm wave spectra; a dissipative, multibarred surf zone; dynamic inner and middle bars; and the attainment of a “transitional transverse bar and rip – rhythmic bar and beach” state during rising wave conditions, underline Seaford Beach as “bimodal”, exhibiting process and morphologic features of both higher and lower-energy beaches. As an example of a beach in a strong-wind bay, Seaford illustrates that not all fetch-limited beaches are low-energy. Furthermore, the presence of infragravity energy in a highly fetch-limited environment indicates that infragravity energy may occur commonly in fetch-limited environments that are subject to periodic strong winds; a process that has remained largely unrecognised.
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| 6. |
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| 7. |
- Goodfellow, Bradley, et al.
(author)
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Deciphering a non-glacial/glacial landscape mosaic in the northern Swedish mountains
- 2008
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In: Geomorphology. - : Elsevier BV. - 0169-555X. ; 93:3-4, s. 213-232
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Journal article (peer-reviewed)abstract
- Relict surfaces contain information on past surface processes and long-term landscape evolution. A detailed investigation of relict non-glacial surfaces in a formerly glaciated mountain landscape of northern Sweden was completed, based on interpretation of colour infrared aerial photographs, analysis in a GIS, and fieldwork. Working backwards from landscape to process, surfaces were classified according to large- and small-scale morphologies that result from the operation of non-glacial processes, the degree of weathering, regolith characteristics, and the style of glacial modification. Surfaces were also compared in the GIS according to elevation, slope angle, and bedrock lithology. The study revealed five types of relict non-glacial surfaces but also two types of extensively weathered glacial surfaces that were transitional to relict non-glacial surfaces, illustrating spatially variable processes and rates of non-glacial and glacial landscape evolution. Rather than being static preglacial remnants, relict non-glacial surfaces are dynamic features that have continued to evolve during the Quaternary. The classification provides hypotheses for landscape evolution that can be field tested through, for example, terrestrial cosmogenic nuclide studies and geochemical analyses of fine matrix materials. The classification may be applicable to relict non-glacial surfaces in other formerly glaciated landscapes
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| 8. |
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| 9. |
- Goodfellow, Bradley
(author)
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Relict non-glacial surfaces in formerly glaciated landscapes
- 2007
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In: Earth-Science Reviews. - : Elsevier BV. - 0012-8252. ; 80:1-2, s. 47-73
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Journal article (peer-reviewed)abstract
- Relict non-glacial surfaces occur within many formerly glaciated landscapes and contain important information on past surface processes and long-term landscape evolution. Relict non-glacial surfaces are distinguishable from glacial surfaces by large-scale morphologies, including rounded summits, fluvial valleys, and cryoplanation terraces and pediments, and the presence of tors, blockfields, and/or saprolites. Preservation during glaciation occurs either through coverage by non-erosive, cold-based, ice or as nunataks. Although surface morphologies and denudation rates indicate a continuous non-glacial surface history since pre-glacial times, relict non-glacial surfaces are dynamic features that have evolved during the Quaternary. Depending on spatial variables such as lithology, slope, regolith cover, and the abundance of fine matrix and water some surfaces are denuding very slowly, while others display more rapid denudation. High spatial variability in denudation rates results in changing surface morphologies over time. Denudation rates also display high temporal variability, with much surface evolution having perhaps occurred soon after the initial onset of glaciation or during paraglacial phases. While some parts of non-glacial landscapes are currently active, others may be largely inactive relicts of past higher energy regimes. Although non-glacial surfaces are dynamic much remains to be determined regarding surface denudation rates and the magnitude of morphological changes over time.
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| 10. |
- Goodfellow, Bradley, et al.
(author)
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Relict non-glacial surfaces in formerly glaciated landscapes: dynamic landform systems?
- 2007
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In: Geophysical Research Abstracts.
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Conference paper (peer-reviewed)abstract
- Relict non-glacial surfaces occur within many formerly glaciated landscapes and containimportant information on past surface processes and long-term landscape evolution(Goodfellow, 2007). While cosmogenic dating has confirmed the antiquity ofrelict non-glacial surfaces, the processes that contribute to their evolution and, consequently,the time scales over which they develop remain poorly understood. Of particularimportance is the possibility that relict non-glacial surfaces may provide geomorphicmarkers for the reconstruction of preglacial landscapes, which would allowsubsequent glacial erosion to be quantified. Furthermore, relict non-glacial surfacesmay also hold information on preglacial and interglacial environmental conditions.An investigation of relict non-glacial surfaces was undertaken through remote sensing,mapping and analysis of surfaces in a GIS, and regolith studies involving cosmogenicdating-, grain size-, X-ray diffraction-, and X-ray fluorescence analyses. Onthe basis of these on-going studies, we show that depending on spatial variables suchas bedrock lithology, slope, regolith thickness, and the abundance of fine matrix andwater some surfaces are denuding very slowly, while others display more rapid denudation.High spatial variability in denudation rates results in changing surface morphologiesover time. Rather than being static preglacial remnants, relict non-glacialsurfaces are dynamic features that have evolved during the Quaternary. While reconstructionsof preglacial landscapes and subsequent quantifications of glacial erosionfrom relict non-glacial surfaces remain valid, the Quaternary evolution of these surfacesshould also be considered.Goodfellow B.W., 2007. Relict non-glacial surfaces in formerly glaciated landscapes.Earth-Science Reviews, 80(1-2): 47-73.
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