Freshening of the Labrador Sea as a trigger for Little Ice Age development

• Published in: Climate of the Past
• Main Authors: Alonso-Garcia, Montserrat, Kleiven, Helga (Kikki) F., McManus, Jerry F., Moffa Sanchez, Paola, Broecker, Wallace S., Flower, Benjamin P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: European Geosciences Union 2017
• Subjects: QE Geology; Arctic; Greenland; Labrador Sea; North Atlantic; Sea ice
• Online Access: https://orca.cardiff.ac.uk/id/eprint/102225/; https://doi.org/10.5194/cp-13-317-2017; https://orca.cardiff.ac.uk/id/eprint/102225/1/Freshening%20of%20the%20Labrador%20Sea%20as%20a%20trigger%20for%20Little%20Ice%20Age%20development.pdf

Arctic freshwater discharges to the Labrador Sea from melting glaciers and sea ice can have a large impact on ocean circulation dynamics in the North Atlantic, modifying climate and deep water formation in this region. In this study, we present for the first time a high resolution record of ice rafting in the Labrador Sea over the last millennium to assess the effects of freshwater discharges in this region on ocean circulation and climate. The occurrence of ice-rafted debris (IRD) in the Labrador Sea was studied using sediments from Site GS06-144-03 (57.29° N, 48.37° W; 3432 m water depth). IRD from the fraction 63–150 µm shows particularly high concentrations during the intervals ∼ AD 1000–1100, ∼ 1150–1250, ∼ 1400–1450, ∼ 1650–1700 and ∼ 1750–1800. The first two intervals occurred during the Medieval Climate Anomaly (MCA), whereas the others took place within the Little Ice Age (LIA). Mineralogical identification indicates that the main IRD source during the MCA was SE Greenland. In contrast, the concentration and relative abundance of hematite-stained grains reflects an increase in the contribution of Arctic ice during the LIA.