Nordic Seas surface ice drift reconstructions: evidence from ice rafted coal fragments during oxygen isotope stage 6
Abstract: Sixteen long sediment cores from the eastern Arctic Ocean, the Fram Strait and the Norwegian- Greenland Sea, documenting 200 000 years of sedimentation, were studied for their qualitative dropstone composition (>500 lain-fraction). In sediments from oxygen isotope stages 1-5, coal parti...
| Main Authors: | , , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1029.1362 http://sp.lyellcollection.org/content/53/1/235.full.pdf |
| Summary: | Abstract: Sixteen long sediment cores from the eastern Arctic Ocean, the Fram Strait and the Norwegian- Greenland Sea, documenting 200 000 years of sedimentation, were studied for their qualitative dropstone composition (>500 lain-fraction). In sediments from oxygen isotope stages 1-5, coal particles are usually subordinate components of the coarse fraction. In contrast o younger deposits, coal content in oxygen isotope stage 6 (186-128 ka) varies between 20 % and 65 % in the eastern Arctic Ocean and the Fram Strait and between 5 % and 20 % in the Norwegian Sea. Southward decreasing coal content and similarities in maturity and petrography of the coals indicate that the coal was transported by iceberg or sea ice rafting more than 1000 km to the south. It is suggested that during intervals of oxygen-isotope stage 6 drifting ice carried abundant coal fragments from the eastern Arctic Ocean southward through the Fram Strait into the eastern Norwegian Sea. Thus, surface circulation was then opposite to that of today. The set of palaeoceanographic data for the northern oceans in Pleistocene times has strongly increased from research of the past decades (Thiede et al. 1990). However, not very much is known about surface currents during the ice ages. Some attempts at recon-struction were made using the quantitative dis-persal patterns of ice rafted sand (Ruddiman 1977a, b) or by computer modelling of the estimated behaviour of a suggested permanent ice covered ocean (LindstrOm & MacAyeal 1986). Other studies deal with surface currents and ice transport in the Norwegian-Greenland |
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