Centennial-to-millennial-scale periodicities of Holocene climate and sediment injections off the western Barents shelf, 75°N |
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| Authors: | M SARNTHEIN S VAN KREVELD H ERLENKEUSER P M GROOTES M KUCERA U PFLAUMANN M SCHULZ |
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| Institution: | Institut für Geowissenschaften, University of Kiel, D-24098 Kiel, Germany;University of Kiel, D-24098 Kiel, Germany;Department of Geology, Royal Holloway University of London, Egham, TW20 0EX, UK;Institut fur Geowissenschaften, University of Kiel, D-24098 Kiel, Germany |
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| Abstract: | At the western continental margin of the Barents Sea, 75°N, hemipelagic sediments provide a record of Holocene climate change with a time resolution of 10-70 years. Planktic foraminifera counts reveal a very early Holocene thermal optimum 10.7-7.7 kyr BP, with summer sea surface temperatures (SST) of 8°C and a much enhanced West Spitsbergen Current. There was a short cooling between 8.8 and 8.2 kyr BP. In the middle and late Holocene summer, SST dropped to 2.5°-5.0°C, indicative of reduced Atlantic heat advection, except for two short warmings near 2.2 and 1.6 kyr BP. Distinct quasi-periodic spikes of coarse sediment fraction (with large portions of lithic grains, benthic and planktic foraminifera) record cascades of cold, dense winter water down the continental slope as a result of enhanced seasonal sea ice formation and storminess on the Barents shelf over the entire Holocene. The spikes primarily cluster near recurrence intervals of 400-650 and 1000-1350 years, when traced over the entire Holocene, but follow significant 885-/840- and 505-/605-year periodicities in the early Holocene. These non-stationary periodicities mimic the Greenland-Formula: See Text]Be variability, which is a tracer of solar forcing. Further significant Holocene periodicities of 230, (145) and 93 years come close to the deVries and Gleissberg solar cycles. |
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