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*Multi-decadal to-century NAO-like marine climate oscillations across the Denmark Strait (~66° N) over the last 2000 cal yr BP


J. T. Andrews and A. E. Jennings

First Authors affiliation

INSTAAR and Department of Geological Sciences, University of Colorado, Boulder, CO 80309, USA


Climate of the Past Discussion

10, 325-343, 2014

Special Issue


In the area of Denmark Strait (~66° N) the two modes of the North Atlantic Oscillation (NAO) are expressed in changes of the northward flux of Atlantic Water and the southward advection of Polar Water in the East Iceland Current. Proxies from marine cores along an environmental gradient from extensive to little or no drift ice, capture low frequency NAO-like variations over the last 2000 cal yr BP. Key proxies are the weight% of calcite, a measure of surface water stratification and nutrient supply, the weight% of quartz, a measure of drift ice transport, and grain-size. Records from Nansen and Kangerlussuaq fjords show variable ice-rafted debris (IRD) records but have distinct mineralogy associated with differences in the fjord catchment bedrock. High-resolution detrended records from Kangerlussuaq Trough show abrupt, significant multi-decadal changes (72 and 56 yr for calcite, and 94 and 65 yr for quartz), and parallel the 2000 yr Arctic summer temperature reconstructions. The calcite minimum occurred ca. 1550 AD whereas the quartz maxima occurred 200 yr earlier. Changes in calcite wt% from N and SW Iceland show similar abrupt changes to those in Kangerlussuaq Trough with an abrupt calcite peak ~1320 AD. Quartz values increased at two N Iceland sites in the last 500 yr whereas values declined in the East Greenland site.


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