10Be records of sediment cores from high northern latitudes: Implications for environmental and climatic changes

Abstract

The "Be records of four sediment cores forming a transect from the Norwegian Sea at 70"N (core 23059) via the Fram Strait (core 23235) to the Arctic Ocean at 86"N (cores 1533 and 1524) were measured at a high depth resolution. Although the material in all the cores was controlled by different sedimentological regimes, the '('Be records of these cores were superimposed by glacial/interglacial changes in the sedimentary environment. Core sections with high loBe concentrations (> 1. 10' at/g) are related to interglacial stages and core sections with low "Be concentrations (< 0.5. 10' at/g) are related to glacial stages. Climatic transitions (e.g., Termination II, 5/6) are marked by drastic changes in the "Be concentrations of up to one order of magnitude. The average "Be concentrations for each climatic stage show an inverse relationship to their corresponding sedimentation rates, indicating that the "Be records are the result of dilution with more or less terrigenous ice-rafted material. However, there are strong changes in the "Be fluxes (e.g., Termination II) into the sediments which may also account for the observed oscillations. Most likely, both processes affected the "Be records equally, amplifying the contrast between lower (glacials) and higher (interglacials) "Be concentrations. The sharp contrast of high and low "'Be concentrations at climatic stage boundaries are an independent proxy for climatic and sedimentary change in the Nordic Seas and can be applied for stratigraphic dating ("Be stratigraphy) of sediment cores from the northern North Atlantic and the Arctic Ocean.

A high resolution authigenic 10Be/9Be record of geomagnetic moment variations over the last 300 ka from sedimentary cores of the Portuguese margin

“…Such a correlation was previously reported [30][31][32] and attributed to a dependence of 10 Be fluxes to glacial /interglacial alternation. However, close examination of …”

Late Quaternary paleoceanography of the Eurasian Basin, Arctic Ocean

“…Vogt et al, manuscript in preparation, 1995], glacial periods also have enhanced terriginous input via IRD; interglacial have lower temgmous input, higher amounts of biogenic sediment consisting of planktonic foraminifers, coccoliths and ostracodes. Calcareous nannofossils [Gard, 1988;Gard and Backman, 1990], high l»Jn and 1 0Se values [Eisenhauer et al, 1994], ostracode faunal data [Cronin et al, 1994], and sedimentologic evidence [C. Vogt et al, manuscript in preparation, 1995] indicate higher sea-surface biologic productivity during the interglacial parts of 100-kyr climatic cycles in this region. Thus, it is generally clear that over longer time periods, the relative abundance of planktonic and benthic calcareous microfossils in the central Arctic Ocean and along some Arctic margins decreased during glacial periods due to influx of ice-rafted siliciclastic material, decreased biologic productivity, and other factors [Stein et al, 1993[Stein et al, , 1994b.…”

Regional variations in provenance and abundance of ice-rafted clasts in Arctic Ocean sediments: implications for the configuration of late Quaternary oceanic and atmospheric circulation in the Arctic

“…Evidence for a thickened Arctic Ocean sea-ice cover in the central Arctic Ocean during glacial periods includes restricted productivity and low sedimentation rates in the recurring stratigraphic intervals of Arctic cores that correspond with glaciation (Clark, 1971;Poore et al, 1993Poore et al, , 1999Darby et al, 1997;Gard, 1988;Eisenhauer et al, 1994;Ishman et al, 1996;Nørgaard-Pedersen et al, 1998;Phillips et al, 1992;Phillips and Grantz, 1997). Glacial icebergs were able to circulate freely beyond the margins of the Arctic Ocean only when the sea-ice sheet that formed in the central Arctic during glacial stages melted and broke up during interglacial stages.…”