HOLOCENE SEDIMENTATION HISTORY OF THE KNIPOVICH RIDGE AREA (THE NORWEGIAN SEA) BASED ON THE ANALYSIS OF MICROFOSSILS

Abstract

Climatic events of the last millennia in the northeastern part of the Norwegian-Greenland basin were reconstructed based on micropaleontological studies of sediments from the AMK-6150 core. New results were obtained from analyses of dinoflagellate cysts, diatoms, and benthic and planktonic foraminifers. These results allow us to infer the time of sediment accumulation and the prevailing natural conditions. According to preliminary data on climatostratigraphy based on the composition of microfossils, the period of sediment formation in the AMK-6150 core does not exceed 7 thousand years. The composition of microfossil assemblages and the results of reconstructions indicate repeated changes in marine environmental conditions during this time. Sediments at the depth of 23-24 cm recorded the beginning of a significant growth of temperature and salinity of surface waters due to a possible increase of the Norwegian Current influence. According to the species and quantitative composition of dinocyst and diatom assemblages, sediments in the short depth range of 14-12 cm accumulated during a period of noticeable decrease in temperature and increased influence of Arctic water masses. The analysis of dinocysts by the method of modern analogues allows reconstruction of the quantitative values of summer paleotemperatures of surface waters and the duration of ice cover. It was found that the cooling episodes and probable formation of seasonal sea ice were possible during the accumulation of sediments at the depths of 29-24, 14-12 and 3-1 cm.