NOAA/WDS Paleoclimatology - Denmark Strait 2000 Year Multiproxy Sediment Data

STUDY NOTES: High resolution geochemical data from sediment cores in the Denmark Strait, North Atlantic covering the past ~2,000 years. Data are from figures from Andrews and Jennings 2014, as follows: Figure 5 JM96-1210 Nansen Fjord Figure 6A: BS1191-K7 Kangerlussuaq Fjord Figure 6B: BS1191-K8 Kangerlussuaq Fjord Figure 7: Sediment sources at site HU93030-019B/MD99-2322 Kangerlussuaq Trough. Figure 8: Calcite and quartz wt% data for BS1191-K7 HU93030-019B/MD99-2322 Kangerlussuaq Trough Figure 9: calcite and quartz data for North Iceland sites MD99-2263, MD99-2269 and B997-316PC Figure 10: Calcite and quartz data at 30-yr intervals for MD99-2269 and MD99-2322 All X-ray diffraction data for HU93030-019B and MD99-2322.
ABSTRACT SUPPLIED BY ORIGINATOR: In the area of Denmark Strait (~66° N), the two modes of the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) 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 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. A comparison between cores on either side of the Denmark Strait (MD99-2322 and MD99-2269) show a remarkable millennial-scale similarity in the trends of the weight% of calcite with a trough reached during the Little Ice Age. However, the quartz records from these two sites are quite different. The calcite records from the Denmark Strait parallel the 2000 yr Arctic summer-temperature reconstructions; analysis of the detrended calcite and quartz data reveal significant multi-decadal-century periodicities superimposed on a major environmental shift occurring ca. 1450 AD.