Holocene climate variability in northernmost Europe |
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| Institution: | 1. Institute of Ecosystem Science, School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK;2. Department of Geography, Durham University, South Road, Durham DH1 3LE, UK;3. Department of Earth Sciences, Durham University, South Road, Durham DH1 3LE, UK;1. Earth and Climate Cluster, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands;2. Laboratoire des Sciences du Climat et de l''Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France;3. INSTAAR and Department of Geological Sciences, University of Colorado, Boulder, CO 80309, USA;4. Department of Geological Sciences, University of Colorado, Boulder, CO 80309, USA;1. Institute of Geography RAS, Staromonetny-29, 119017, Staromonetny, Moscow, Russia;2. Tomsk State University, Tomsk, Russia;3. Department of Geosciences, University of Massachusetts, Amherst, MA 012003, USA;4. British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK;5. Institute of Particle Physics, ETH Zurich, 8093 Zurich, Switzerland;6. Institute of Geography, University of Zurich, 8057 Zurich, Switzerland;7. Université Paris 1 Panthéon-Sorbonne, CNRS Laboratoire de Géographie Physique, 92195 Meudon, France;8. Antarctic Research Centre, Victoria University Wellington, New Zealand;9. Department of Earth Science, University of Bergen, N-5020 Bergen, Norway;10. Uni Research Klima, Bjerknes Centre for Climate Research, N-5020 Bergen Norway;11. Department of Geology, University of Cincinnati, Cincinnati, OH 45225, USA;12. Institute of Geography and Oeschger Centre for Climate Change Research, University of Bern, Switzerland;13. Department of Geology, The College of Wooster, Wooster, OH 44691, USA;14. Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA;1. School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, United Kingdom;2. Department of Geography, Durham University, South Road, Durham DH1 3LE, United Kingdom;1. Institute of Geography, Leipzig University, Leipzig, Germany;2. School of Environment and Development, University of Manchester, Manchester, United Kingdom;3. Faculty of Earth Sciences, University of Iceland, Reykjavik, Iceland;4. Renard Centre of Marine Geology, Ghent University, Ghent, Belgium;5. Institut des Sciences de l’Evolution, Montpellier University, France;6. GFZ German Research Centre for Geosciences, Section 5.2 – Climate Dynamics and Landscape Evolution, Potsdam, Germany;7. Faculté Pluridisciplinaire Nador, Université Mohamed I Oujda, Morocco;8. Faculty of Geosciences, Tübingen University, Germany;9. Institute of Geography, Osnabruck University, Osnabruck, Germany;10. Max Planck Institute for Evolutionary Anthropology, Department of Human Evolution, Leipzig, Germany;11. Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany;12. Department of Earth Sciences, ETH Zurich, Switzerland;13. Institute of Geophysics and Geology, Leipzig University, Leipzig, Germany;14. Institut National des Sciences de l''Archéologie et du Patrimoine, Rabat, Morocco;1. Department of Earth, Environmental and Planetary Sciences, Brown University, 324 Brook Street, Providence, RI, 02912, USA;2. Institute at Brown for Environment and Society, Brown University, 324 Brook Street, Providence, RI, 02912, USA;3. Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, 216 UCB, Boulder, CO, 80309, USA;4. NOAA’s National Centers for Environmental Information, Center for Weather and Climate, 325 Broadway, Boulder, CO, 80309, USA;5. The Ecosystems Center, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA;1. Department of Earth Science, University of Bergen, Allégaten 41, 5007, Bergen, Norway;2. Bjerknes Centre for Climate Research, Bergen, Norway;3. Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA;4. Department of Geology, College of William & Mary, Williamsburg, VA 23185, USA;5. Department of Geosciences, University of Massachusetts, Amherst, MA 01003, USA |
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| Abstract: | The sediments of a small lake on Nordkinnhalvøya, Finnmark, Norway, were investigated in order to test the hypothesis that this region was sensitive to centennial–millennial climatic fluctuations during the Holocene related to changes in ocean circulation. Sedimentation at the site began during the Younger Dryas, although the site chronology, developed using a series of 14C age measurements, reveals an early Holocene hiatus in accumulation. Pollen analysis confirmed that the regional vegetation responded to Holocene climatic variability at centennial–millennial time scales and provided data used to make quantitative palaeoclimate reconstructions. The latter indicate that marked changes in seasonality characterised Holocene climatic fluctuations. Intervals with warmer summers, higher temperature sums and higher precipitation, but cooler winters and generally reduced moisture availability, alternated with intervals with cooler summers, lower temperature sums, lower precipitation, warmer winters and greater moisture availability. The former conditions were more prevalent between ca 8950 and 3950 cal BP, whereas the latter were predominant before ca 8950 and since ca 3950 cal BP. Sediment geochemistry indicates minerogenic material deposited in the lake was probably derived from two or more distinct sources or transport pathways that differed in their responses to palaeoclimatic conditions. A series of cryptotephras were located, although the small size of the shards rendered them unsuitable for electron microprobe analyses. Time-series analysis of pollen analytical and sediment geochemical data indicates that each exhibits statistically significant periodic behaviour (at periods of ca 190, 410, 1050, 1650 and 1810 yr). The periods detected suggest this behaviour may reflect regional expression of climate system responses to solar variability and/or of effects upon tides and ocean circulation of periodic lunar orbital variation. Comparison with records of fluctuations in ocean thermohaline circulation strength indicate some concordance with respect to timing of warmer and cooler intervals, but also some differences. The 8.2 ka event, that is evident in marine records from the Barents Sea, is clearly expressed by both the palaeovegetation and geochemical records. Distinctive temporal behaviour of the palaeovegetation and of different geochemical components indicates complexity in the underlying causes and mechanisms of regional climatic variability; ocean circulation variability alone cannot account for the complex climatic variability observed. |
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