A robust, multisite Holocene history of drift ice off northern Iceland: implications for North Atlantic climate

• Main Authors: Andrews, John T., Darby, Dennis, Eberle, Dennis, Jennings, Anne E., Moros, Matthias, Ogilvie, Astrid
• Format: Text
• Language: unknown
• Published: DigitalCommons@University of Nebraska - Lincoln 2009
• Subjects: Ice rafted debris; Iceland; quartz; drift ice; Holocene; Arctic basin; Earth Sciences; Geology; Oceanography and Atmospheric Sciences and Meteorology; Other Earth Sciences; Other Environmental Sciences; Arctic; Arctic Ocean; Arctic Basin; Climate change; North Atlantic
• Online Access: https://digitalcommons.unl.edu/usgsstaffpub/909; https://digitalcommons.unl.edu/context/usgsstaffpub/article/1906/viewcontent/Andrews_HOLOCENE_2009_A_robust_multisite_Holocene.pdf

An important indicator of Holocene climate change is provided by evidence for variations in the extent of drift ice. A proxy for drift ice in Iceland waters is provided by the presence of quartz. Quantitative xray diffraction analysis of the < 2 mm sediment fraction was undertaken on 16 cores from around Iceland. The quartz weight (wt.)% estimates from each core were integrated into 250-yr intervals between −0.05 and 11.7 cal. ka BP. Median quartz wt.% varied between 0.2 and 3.4 and maximum values ranged between 2.8 and 11.8 wt.%. High values were attained in the early Holocene and minimum values were reached 6–7 cal. ka BP. Quartz wt.% then rose steadily during the late Holocene. Our data exhibit no correlation with counts on haematite-stained quartz (HSQ) grains from VM129-191 west of Ireland casting doubt on the ice-transport origin. A pilot study on the provenance of Fe oxide grains in two cores that cover the last 1.3 and 6.1 cal. ka BP indicated a large fraction of the grains between 1 and 6 cal. ka BP were from either Icelandic or presently unsampled sources. However, there was a dramatic increase in Canadian and Russian sources from the Arctic Ocean ~1 cal. ka BP. These data may indicate the beginning of an Arctic Oscillation-like climate mode.