Linking Stratigraphy on the Lomonosov Ridge With Standard Lithological Units of the Amerasian Basin, Arctic Ocean
2006 (English)In: AGU Fall Meeting 2006Eos Trans. AGU, 87(52), Fall Meeting, 2006Conference paper (Other academic)
AB: Short sediment cores taken from the ice-island T3 between 1963 and 1973 were used by Clark et al. (1980) to establish a lithological classification for the Amerasian Basin in the Arctic Ocean. Over a 310 cm long stratigraphic section, synthesized from 67 cores, 13 units were recognized and labeled A to M. This lithostratigraphic model has since been applied to correlate sediment cores over large distances on the Amerasian side, i.e., between cores on the Alpha Ridge, the Northwind Ridge and the Mendeleev Ridge. The chronostratigraphy for this lithostratigraphic model was developed by the identification of the Brunhes- Matuyama paleomagnetic reversal boundary (781 ka) and the assumption of linear sedimentation rates in the synthesized lithologic model. However, recent studies have shown that this measured magnetic polarity change rather represents a short-time excursion within the Brunhes chron, implying an order of magnitude higher sedimentation rates than originally assumed. We have investigated whether it is possible to link the lithostratigraphy from the Alpha Ridge to cores taken on the Lomonosov Ridge which, in turn, have been linked to cores in the Eurasian Basin. The cores selected for this comparison were cores B-8 and B-24 from the LOREX ‘79 ice island drift expedition, core PS2185-6 from the ARK-VIII/3 expedition of 1991 and core 96/12- 1pc from the Arctic Ocean 96 expedition. Averaged sedimentary proxies (paleomagnetism, grain size, and microfossil abundance) from selected sets of T3 cores and published by Clark et al. (1980), have been used here to correlate the included Lomonosov Ridge cores. A lithostratigraphic connection between the Amerasian Basin and the Lomonosov Ridge stratigraphies was partly successfully established, although Clark's lithostratigraphic units A to M could not be recognized in the Lomonosov Ridge. Nevertheless, the established correlations clearly show that the Amerasian Basin is characterized by lower sedimentation rates when compared to the rates obtained from the Lomonosov Ridge and the Eurasian Basin , but that the Amerasian Basin rate are not as low as Clark and others previously suggested.
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IdentifiersURN: urn:nbn:se:su:diva-19502OAI: oai:DiVA.org:su-19502DiVA: diva2:186026