Blar i forfatter "Ingólfsson, Ólafur"

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    • Arctic Ocean glacial history 

      Jakobsson, Martin; Andreassen, Karin; Bjarnadóttir, Lilja Rún; Dove, Dayton; Dowdeswell, Julian A.; England, John H.; Funder, Svend; Hogan, Kelly; Ingólfsson, Ólafur; Jennings, Anne; Krog Larsen, Nikolaj; Kirchner, Nina; Landvik, Jon Y.; Mayer, Larry; Mikkelsen, Naja; Möller, Per; Niessen, Frank; Nilsson, Johan; O'Reagan, Matt; Polyak, Leonid; Nørgaard-Pedersen, Niels; Stein, Ruediger (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-11-14)
      While there are numerous hypotheses concerning glacial–interglacial environmental and climatic regime shifts in the Arctic Ocean, a holistic view on the Northern Hemisphere's late Quaternary ice-sheet extent and their impact on ocean and sea-ice dynamics remains to be established. Here we aim to provide a step in this direction by presenting an overview of Arctic Ocean glacial history, based on the ...

    • Bycatch reduction in the deep-water shrimp (Pandalus borealis) trawl fishery by increasing codend mesh openness 

      Jacques, Nadine; Cerbule, Kristine; Pettersen, Hermann; Herrmann, Bent; Ingólfsson, Ólafur; Sistiaga, Manu Berrondo; Larsen, Roger B.; Brinkhof, Jesse; Grimaldo, Vela Eduardo; Brčić, Jure; Lilleng, Dagfinn (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-03)
      In most trawl fisheries, drag forces tend to close the meshes in large areas of diamond mesh codends, negatively affecting their selective potential. In the Barents Sea deep-water shrimp (Pandalus borealis) trawl fishery, selectivity is based on a sorting grid followed by a diamond mesh codend. However, the retention of juvenile fish as well as undersized shrimp is still a problem. In this study, ...

    • A Driftwood-Based Record of Arctic Sea Ice During the Last 500 Years From Northern Svalbard Reveals Sea Ice Dynamics in the Arctic Ocean and Arctic Peripheral Seas 

      Hole, Georgia M.; Rawson, Thomas; Farnsworth, Wesley Randall; Schomacker, Anders; Ingólfsson, Ólafur; Macias-Fauria, Marc (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-15)
      We present a 500-year history of naturally felled driftwood incursion to northern Svalbard, directly reflecting regional sea ice conditions and Arctic Ocean circulation. Provenance and age determinations by dendrochronology and wood anatomy provide insights into Arctic Ocean currents and climatic conditions at a fine spatial resolution, as crossdating with reference chronologies from the ...

    • Holocene glacial history of Svalbard: Status, perspectives and challenges 

      Farnsworth, Wesley Randall; Allaart, Lis; Ingólfsson, Ólafur; Alexanderson, Helena; Forwick, Matthias; Noormets, Riko; Retelle, Michael J.; Schomacker, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-29)
      We synthesize the current understanding of glacier activity on Svalbard from the end of the Late Pleistocene (12,000 yrs. before present) to the end of the Little Ice Age (<i>c.</i> 1920 AD). Our glacier history is derived from the SVALHOLA database, the first compilation of Holocene geochronology for Svalbard and the surrounding waters, including over 1,800 radiocarbon, terrestrial cosmogenic nuclide ...

    • Holocene precipitation seasonality in northern Svalbard: Influence of sea ice and regional ocean surface conditions 

      Kjellman, Sofia Elisabeth; Schomacker, Anders; Thomas, Elizabeth K.; Håkansson, Lena; Duboscq, Sandrine; Cluett, Allison; Farnsworth, Wesley R.; Allaart, Lis; Cowling, Owen; McKay, Nicholas P.; Brynjólfsson, Skafti; Ingólfsson, Ólafur (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-06-13)
      Arctic precipitation is predicted to increase in the coming century, due to a combination of enhanced northward atmospheric moisture transport and local surface evaporation from ice-free seas. However, large model uncertainties, limited long-term observations, and high spatiotemporal variability limit our understanding of these mechanisms, emphasizing the need for paleoclimate records of precipitation ...

    • Ocean-rafted pumice constrains postglacial relative sea-level and supports Holocene ice cap survival 

      Farnsworth, Wesley Randall; Blake Jr., Wesley; Gudmundsdottir, Esther Ruth; Ingólfsson, Ólafur; Larsen, Gudrún; Óladóttir, Bergrún Arna; Schomacker, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-24)
      Distally deposited tephra from explosive volcanic eruptions can be a powerful tool for precise dating and correlation of sedimentary archives and landforms. However, the morphostratigraphic and chronological potential of ocean-rafted pumice has been under-utilized considering its long observational history and widespread distribution on modern and palaeo-shorelines around the world. Here we analyze ...

    • Persistence of Holocene ice cap in northeast Svalbard aided by glacio-isostatic rebound 

      Farnsworth, Wesley Randall; Ingólfsson, Ólafur; Brynjólfsson, Skafti; Allaart, Lis; Kjellman, Sofia Elisabeth; Kjær, Kurt H.; Larsen, Nicolaj K.; Macias-Fauria, Marc; Siggaard-Andersen, Marie-Louise; Schomacker, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-29)
      The deglaciation of the Svalbard-Barents Sea Ice Sheet was driven by relative sea-level rise, the incursion of North Atlantic waters around Spitsbergen, and increasing summer insolation. However, ice retreat was inter rupted by asynchronous re-advances that occurred into high relative seas, during a period associated with warm regional waters and elevated summer temperatures. Better understanding ...

    • Postglacial relative sea level change and glacier activity in the early and late Holocene: Wahlenbergfjorden, Nordaustlandet, Svalbard 

      Schomacker, Anders; Farnsworth, Wesley Randall; Ingólfsson, Ólafur; Allaart, Lis; Håkansson, Lena; Retelle, Michael; Marie-Louise, Siggaard-Andersen; Korsgaard, Niels J.; Rouillard, Alexandra; Kjellman, Sofia Elisabeth (Journal article; Peer reviewed, 2019-05-01)
      Sediment cores from Kløverbladvatna, a threshold lake in Wahlenbergfjorden, Nordaustlandet, Svalbard were used to reconstruct Holocene glacier fluctuations. Meltwater from Etonbreen spills over a threshold to the lake, only when the glacier is significantly larger than at present. Lithological logging, loss-on-ignition, ITRAX scanning and radiocarbon dating of the cores show that Kløverbladvatna ...

    • Submarginal drumlin formation and late Holocene history of Fláajökull, southeast Iceland 

      Jónsson, Sverrir A.; Benediktsson, Ívar Örn; Ingólfsson, Ólafur; Schomacker, Anders; Bergsdóttir, Helga Lucia; Jacobson Jr., William R.; Linderson, Hans (Journal article; Tidsskriftartikkel; Peer reviewed, 2016)
      Fláajökull is a non-surging outlet glacier draining the south-eastern part of the Vatnajökull, southeast Iceland. Fláajökull was stationary or advanced slightly between 1966 and 1995 and formed a prominent end moraine. Glacial retreat since then has revealed a cluster of 15 drumlins. This study focuses on the morphology and sedimentology of the drumlins. They are 100–600 m long, 40–130 m wide, and ...

    • Vedde Ash constrains Younger Dryas glacier re-advance and rapid glacio-isostatic rebound on Svalbard 

      Farnsworth, Wesley Randall; Ingólfsson, Ólafur; Mannerfelt, Erik S.; Kalliokoski, Maarit H.; Gudmundsdottir, Esther Ruth; Retelle, Michael; Allaart, Lis; Brynjólfsson, Skafti; Furze, Mark; Hancock, Holt John; Kjær, Kurt H.; Pieńkowski, Anna J.; Schomacker, Anders (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-09)
      The distal deposition of tephra from explosive volcanism has the potential to geochronologically constrain sedimentary archives and landforms. With this technique, we constrain a Late Glacial glacier re-advance on Svalbard and suggest that glacioisostatic emergence rates during the Younger Dryas chronozone were at least three times greater than previous estimates. The identification of cryptotephra ...