Environmental change in eastern Greenland during the last 1300 years: evidence from foraminifera and lithofacies in Nansen Fjord, 68°N

Abstract

Lithofacies and benthic foraminiferal analyses of two sediment cores (BS1191-K13B and K14) from Nansen Fjord, eastern Greenland, show evidence of changing oceanographic and sea-ice conditions from AD 730 to the present. Radiocarbon dates on foraminifera provide century-scale resolution of events, but the frequency of events between dated levels can be estimated with a resolution of approximately 4 to 9 years per centimetre of core. Unstratified glacial-marine diamicton with a calcareous foraminiferal fauna gives way to interstratified diamicton and mud with a predominantly agglutinated foraminifera. The diamictons represent periods of season ally open water with strong continuous iceberg rafting. Mud layers were deposited during intervals of prolonged sea-ice cover. The evidence suggests that the climate in the region of Nansen Fjord was warmer and more stable than today during a 'Medieval Warm Period' between c. AD 730 to 1100. Variable climatic conditions with frequent intervals of severe cold characterize a 'Little Ice Age' type interval from c. AD 1630 to 1900. An earlier cold interval culminated c. AD 1370. The record is similar to the 1000-yr-long Icelandic sea-ice record and, to a lesser extent, to the central Greenland Crete ice-core record.