北冰洋; 古气候与古海洋学; 北半球冰盖; 晚第四纪
北冰洋西部表层沉积物特征，生源组分，冰筏碎屑和浮游有孔虫氧碳同位素所反映的冰融水界限，营养和生产力，温盐，及两股洋流变化均与现代海洋环境相一致，为晚第四纪古海洋学研究提供可靠依据。研究结果显示楚科奇海盆N.pachyderma s (Nps)的18O和13C值分别出现7次明显偏轻，可能响应于提高的海冰形成速率，导致轻同位素卤水下沉和生产。偏轻的Nps18O和13C值与温暖的大西洋水和淡水的输入无关。楚科奇海盆可识别出7个冰筏碎屑事件，它们出现在冰消期和间冰期，被大冰块或者冰山所夹带，通过加拿大北极群岛的麦克卢尔海峡冰流输出到波弗特海，并被波弗特环流输送至楚科奇海盆。这些冰筏碎屑事件不仅指示粗颗粒物来源和冰山输出事件，而且还反映波弗特环流和北美冰盖变化历史。楚科奇海盆间冰期低的TOC和Opal含量可能反映海冰覆盖减少，水柱通气作用好，底层水富氧，TOC降解和Opal溶解作用增强，保存在沉积物中的TOC和Opal减少；而冰期相对高的TOC和Opal含量可能反映海冰覆盖扩大，水柱通气作用差，底层水少氧，TOC降解和Opal溶解作用减弱，保存在沉积物中的TOC和Opal增多。
Multiple proxies indicated paleoceanographic conditions have been built upon relative investigations among appearance features, biogenic components, oxygen and carbon isotopes, sedimentology and geochemistry of the surface sediments collected in the western Arctic Ocean, which goes along with modern oceanic environmental parameters, melt-water boundary, nutrients and productivity, temperature and salinity, two currents, providing a base for paleoceanographic study. Investigated results show that light excursions in N.pachyderma s.(Nps) 18O and 13C happened seven times, likely indicating the production and sinking of isotopically light brines caused by enhanced rate of the sea ice formation. Because concomitant decrease occurred in planktonic foraminiferal abundance and ice-rafted detritus (IRD), these light Nps 18O and 13C values unlikely reflect inputs of freshwater and warm Atlantic waters. Identified seven IRD events appeared in interglacials and deglacials in the Chukchi Basin. These IRD carried in massive icebergs were exported to the Beaufort Sea through the M'Clure Strait Ice Stream, Canadian Arctic Archipelago, and then transported into the Chukchi Basin by the Beaufort Gyre. Therefore, the IRD events in the Chukchi Basin not only indicate the provenance of coarser detritus and ice export events, but also reflect the evolutionary histories of the Beaufort Gyre and North American ice sheet. In the interglacial Chukchi Basin, low TOC and opal contents suggest that although lessening sea ice coverage and more nutrition supply enhanced sea surface productivity, well-ventilated and oxygenated bottom water, together with reinforcing degradation and dissolution, resulted in decreasing TOC and opal contents preserved in the sediments. In the glacial Chukchi Basin, high TOC and opal contents suggest that although extensive sea ice coverage and short of nutrition supply reduced sea surface productivity, bad-ventilated and anoxic bottom water, together with weakening degradation and dissolution, led to increasing TOC and opal contents preserved in the sediments.