| 1. |
- Ferraro, Mattia, et al.
(författare)
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Multi-century reconstruction of environmental conditions in Lurefjorden, Norway.
- 2024
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Ingår i: 24th Nordic Geological Winter Meeting, 10-12th Jan, 2024, Gothenburg, Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Benthic foraminiferal assemblages are identified to reconstruct changes in environmental conditions over the last few centuries in Lurefjorden, a western Norwegian fjord. From ca. 1970 until present days the relative abundance of Brizalina skagerrakkensis, an efficient bio-indicator for organic matter fluxes, is enhanced relative to the preceding time interval. Hence, our results suggest that there is an increase of the organic matter within the Lurefjorden basin in the last 50 years. Over the same period, there is also an increase in the absolute abundance of agglutinated species, indicating lower oxygen concentration in the water. A lowering of the oxygen concentrations may have taken place as a response of a greater oxygen consumption caused by a higher organic matter supply in the water column. Accoridng to Aksnes (2009), Lurefjorden was subject to an increased freshening of Norwegian coastal waters (NCW), which has led to a decrease in sunlight penetration into the water column, affecting the oxygen levels and the behavior of marine life within the basin, between 1935 and 2007. Furthermore, we used diversity indices to study the ecological status of the area, showing significant growth in diversity, abundance, and richness within the benthic foraminiferal community over the past 50 years. Our observations highlight that an increase in the input of organic matter over the last century has led to a change in the benthic foraminifera community in the Lurefjorden basin.
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| 2. |
- Brandt, S. Anders, 1970-, et al.
(författare)
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3D geovisualization as a communication and analysis tool in fluvial geomorphology
- 2004
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Ingår i: Geoinformatics 2004. - Gävle : Gävle University Press. - 919749481X ; , s. 339-346
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Konferensbidrag (refereegranskat)abstract
- The fields of hydrology and fluvial geomorphology get more and more attention in the general public. The reason for this is changed climate patterns with increased frequencies of storms and river flooding and as a result changed geomorphology and living conditions for the inhabitants of the area. With the development of 3D geovisualization, hydrological and geomorphological processes can be better simulated and visualized. Thus not only the domain specialists, but also the general public can appreciate very complex hydrological processes and resulting geomorphology. This is of great value since a high frequency of storms and flooding has been a big issue for politicians, planners, and the general public. It is in this sense that 3D geovisualization can be an important tool for analysis and communication. Complex hydrological and geomorphological processes can be effectively simulated and analyzed by the domain specialists while efficient and effective visualization provides a common platform for communication among domain specialists and the general public. This paper will discuss and illustrate these issues using a case study of geomorphology along the Reventazón River, downstream from the Cachí Reservoir in Costa Rica, due to the release of extreme amounts of sediment during flushing of the reservoir.
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| 3. |
- Brandt, S. Anders, 1970-
(författare)
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Conceptualization of hydraulic and sedimentary processes in downstream reaches during flushing of reservoirs
- 2005
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Ingår i: Proceedings of the XXXI IAHR Congress [Elektronisk resurs]. - Seoul : Korea Water Resources Association. - 8987898237 ; , s. 2577-2588
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Konferensbidrag (refereegranskat)abstract
- The main focus of this paper is to describe the active hydraulic and sedimentary processes in downstream river reaches during flushing of sediments from reservoirs. During flushing extreme amounts of sediment may be released. Therefore, these processes are different than those downstream from dams and reservoirs not subjected to flushing. Hence, also the effects differ, which knowledge of may be of value for biologists, etc. During flushing of a reservoir a wave will be released to the downstream reaches. This wave can be divided into one water part and one sediment part. Initially they are in phase with each other, but with increased distance downstream from the dam, the transported sediment lags behind the water due to different traveling velocities. The paper treats when and where sedimentation occurs, and how this is related to the different traveling velocities of water and sediment. Also included are discussions on how the downstream effects during flushing differ from non-flushing effects, how visualization of effects can enhance both the analysis and communication with planners, politicians, etc., as well as discussions on how the studies of these effects can benefit from improved field-work methods.
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| 4. |
- Bornmalm, Lennart, 1956, et al.
(författare)
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The geopark concept and landscape sustainability, case study in Bohuslan, Sweden
- 2021
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Ingår i: International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM. - : STEF92 Technology. - 9786197603200
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Konferensbidrag (refereegranskat)abstract
- A Geopark is a demarcated area with particularly interesting geologic heritage. Since the physical landscape is intimately related to both cultural and ecological characteristics, knowledge about geological sites can be essential for management of the resources in these settings. In this context, we suggest the term “Landscape Geopark” in order to stress the regional system perspective. Therefore, various stakeholders need to be included in Geopark planning, including researchers, tourists, seasonal and permanent residents, government offices, NGOs, and local industry. The archipelago and coastal landscape in Bohuslan, along the Swedish west coast, have uniquely influenced historical development of and changes in fishing, farming, and tourism. Stakeholder influence is centrally important for the sustainable, landscape-scale management of both economy and geoheritage. We use conceptual modelling of “system” components and processes to include the qualitative and quantitative information from relevant research and local stakeholders. In particular, the model aims to address the likely consequences in 20 years if a Geopark is or is not established. Although geoheritage is always site specific, Geopark models will allow comparisons between sites and information exchange, for instance in the ongoing PLATFORM project.
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| 5. |
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| 6. |
- Buckland, Philip I., 1973-, et al.
(författare)
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The Strategic Environmental Archaeology Database : a resource for international, multiproxy and transdisciplinary studies of environmental and climatic change
- 2015
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Konferensbidrag (refereegranskat)abstract
- Climate and environmental change are global challenges which require global data and infrastructure to investigate. These challenges also require a multi-proxy approach, integrating evidence from Quaternary science and archaeology with information from studies on modern ecology and physical processes among other disciplines. The Strategic Environmental Archaeology Database (SEAD http://www.sead.se) is a Swedish based international research e-infrastructure for storing, managing, analysing and disseminating palaeoenvironmental data from an almost unlimited number of analysis methods. The system currently makes available raw data from over 1500 sites (>5300 datasets) and the analysis of Quaternary fossil insects, plant macrofossils, pollen, geochemistry and sediment physical properties, dendrochronology and wood anatomy, ceramic geochemistry and bones, along with numerous dating methods. This capacity will be expanded in the near future to include isotopes, multi-spectral and archaeo-metalurgical data. SEAD also includes expandable climate and environment calibration datasets, a complete bibliography and extensive metadata and services for linking these data to other resources. All data is available as Open Access through http://qsead.sead.se and downloadable software. SEAD is maintained and managed at the Environmental Archaeology Lab and HUMlab at Umea University, Sweden. Development and data ingestion is progressing in cooperation with The Laboratory for Ceramic Research and the National Laboratory for Wood Anatomy and Dendrochronology at Lund University, Sweden, the Archaeological Research Laboratory, Stockholm University, the Geoarchaeological Laboratory, Swedish National Historical Museums Agency and several international partners and research projects. Current plans include expanding its capacity to serve as a data source for any system and integration with the Swedish National Heritage Board's information systems. SEAD is partnered with the Neotoma palaeoecology database (http://www.neotomadb.org) and a new initiative for building cyberinfrastructure for transdisciplinary research and visualization of the long-term human ecodynamics of the North Atlantic funded by the National Science Foundation (NSF).
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| 7. |
- Hauber, Ernst, et al.
(författare)
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DEBRIS FLOW FANS AND PERMAFROST LANDFORMS ON SVALBARD (NORWAY): TERRESTRIAL ANALOGUES FOR MARTIAN MID-LATITUDE PERIGLACIAL LANDSCAPES.
- 2010
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Ingår i: 41st Lunar and Planetary Science Conference. ; :1922
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Konferensbidrag (refereegranskat)abstract
- Many young landforms on Mars that were probably formed by exogenic processes show a latitude- dependent geographic distribution. They include surface mantling, lobate debris aprons, lineated valley fill, and concentric crater fill, viscous flow features, gullies, and patterned ground. Collectively, these landforms are hypothesized to represent the surface records of Martian ice ages that were induced by astronomical forcing and associated climate changes. Previous studies often considered just one of the features in isolation (e.g., gullies), without taking into account the geomorphologic context. A more comprehensive investigation of the full assemblage of landforms (landscape analysis), however, has the potential to reduce the ambiguity in interpreting landforms (the problem of equifinality, e.g., in the case of pingos), and to reveal the evolution of the climatic environment in more detail. Here we present permafrost landforms of Svalbard (Norway) as useful terrestrial analogues for the suite of possible periglacial landforms that are typically found at mid-latitudes on Mars. We build on our previous investigations of gullies and fans, and include a number of classical periglacial landforms (patterned ground, rock glaciers, pingos) that all have close morphological analogues on Mars. Based on this comparison, we propose an evolutionary scenario which helps to understand the sequential formation of the Martian landforms into their present state.
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| 8. |
- Johnson, Mark D., 1954, et al.
(författare)
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SUBMARINE PUSH MORAINES OF THE MIDDLE SWEDISH END MORAINE ZONE
- 2011
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Ingår i: Geological Society of America abstracts with programs Minneapolis 2011.
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Konferensbidrag (refereegranskat)abstract
- During the Younger Dryas cold event (YD), the Scandinavian Ice Sheet formed the Middle Swedish end-moraine zone (MSEMZ) in south-central Sweden. The area around Skara was below sea level during the YD, and thick marine, varved clay was deposited proglacially on scoured bedrock in the ocean prior to, during, and after the YD. Recent highway exposures in four of the seven ridges in the MSEMZ reveal that, during overall retreat, the ice margin oscillated and, during each oscillation, deformed the marine clay into moraine ridges. The push moraines have little to no till, and then only on the proximal sides. A range of deformation structures are present including folded-and-thrusted to remobilized varved clay. At Ledsjö, a double oscillation is apparent with a grounding-line fan of sand formed between the two oscillations, which was then deformed. The grounding-line-fan sands are faulted and boudinized within 100 m of the former ice margin. Sand in boudins in places retains primary sedimentary structures, but elsewhere show fluidized flow. Farther up-ice, the clay and sands are complexly sheared along down-glacier-dipping reverse faults of several scales (cm to 10´s of m) indicating a subglacial tensional environment. At Ledsjö and Gullhammar, an upper, structureless clay likely represents proglacial, submarine, mudflow sediment deposited on the distal slope of the moraine. These exposures provide models for recent submarine push moraines imaged in fjords in Norway and Svalbard.
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| 9. |
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| 10. |
- Johnson, Mark D., 1954, et al.
(författare)
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SOUTHERN LAURENTIDE ICE SHEET DEAD-ICE TOPOGRAPHY: THE ‘WISCONSIN VIEW' AND NEW OPPORTUNITIES
- 2011
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Ingår i: Geological Society of America abstracts with programs Minneapolis 2011.
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Konferensbidrag (refereegranskat)abstract
- Much of the Late Glacial Maximum margin of the Laurentide Ice Sheet in Wisconsin is marked by extensive tracts of dead-ice topography. These areas are characterized by numerous irregular hummocks and swales occurring together in a band parallel to the former ice-margin position and extending several kilometers up ice. Ice-walled-lake plains are a common feature in these landscapes. We have analyzed the geomorphology and internal composition of these hummocks while making county maps throughout the state. This dead-ice topography is produced by gradual melting of stagnant ice that had thick supraglacial debris. The supraglacial debris was derived from the ice bed by freezing-on, thrusting, and stacking near the margin. There is abundant evidence that the ice lobes that left behind hummocks topography advanced into permafrosted terrain and, in many cases, likely at fast-flow rates (surging or streaming). These two factors, along with up-gradient bed slopes in places, accentuated the marginal thrusting processes and increased the amount of supraglacial debris. In places, preferred orientation of hummocks likely reflects structures in the parent ice. The presence of tunnel channels cutting through hummocky terrains is also an expression of ice with a frozen toe and rapid ice flow. Following stagnation, the presence of permafrost controlled the rate and timing of dead-ice melting.
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