中文摘要：

通过对北冰洋西部楚科奇海台P31孔沉积物进行岩性特征和颜色旋回分析、XRF元素扫描、AMS14 C测年、有孔虫丰度统计、筏冰碎屑（IRD）（〉250和〉154μm）含量分析以及粒度组成的综合研究,建立了该孔的地层年代框架,其沉积物被划分为MIS 3-MIS 1的沉积序列。自MIS 3以来,楚科奇海台P31孔可以识别出5个IRD事件,它们分别出现在晚MIS 1、MIS 2和早中MIS 3期。这些IRD主要被来自加拿大北极群岛的冰山或者大块冰所携带,随波弗特环流搬运至楚科奇海台并卸载到海底,这不仅反映了晚第四纪冰期-间冰期旋回中北美冰盖的崩塌事件,还反映了波弗特环流的变化历史。粒度组分变化表明,细砂级组分主要来自于冰山或大冰块的搬运,因为其高值对应于IRD的高值,粉砂级组分可能主要来自于海冰的搬运,而黏土级组分主要由波弗特环流和雾状层所搬运。两个敏感组分（5～13和110～176μm）含量的变化呈现明显对称性分布,后者的变化对应于IRD的变化,前者可能指示了物源和沉积作用后期的影响。该孔MIS3-MIS1的沉积速率分别为2.2、0.16和1.6cm/ka,平均沉积速率约为1.2cm/ka。与北冰洋其他海区沉积速率资料对比显示,海冰边缘地区沉积速率较高,而永久性海冰覆盖区沉积速率低较。水深越浅,越靠近陆架物源区,沉积速率越高,纬度越高的门捷列夫-阿尔法脊和加拿大海盆区,沉积速率越低。

英文摘要：

Terrigenous components in the core P31 from the Chukchi Plateau, western Arctic Ocean, have been investigated to reconstruct source regions and related climate changes. Together with AMS14C dating, the stratigraphy of the core was established by a combination of variations of lithological features, color cycles, XRF scanned elements content, foraminifera abundance, Ice Rafted Detritus （IRD, 〉250 μm and 〉154 μm）events and grain size components. The Core P31 extends back to the Marine Isotope Stage （MIS） 3. A total of five IRD events were distinguished during the late MIS 1, MIS 2 and early to mid MIS 3. These IRD, transported by sea ice and icebergs, and brought to the Chukchi Plateau, by the Beaufort Gyre, might be exported from the M＇Clure Strait Ice Stream, Canadian Arctic Archipelago. They are indicators of the collapse events of North American Ice Sheet （NAIS） and the evolutionary history of the Beaufort Gyre since MIS 3. Grain size components changes show that the sand components, which correspond to the high IRD size fraction, might be transported by icebergs; but the silt components might be mainly transported by sea ice, and the clay component was probably mainly carried by the Beaufort Gyre. The variation of two sensitive components （5-13 μm and 110-176 μm） present clear symmetric distribution, the coarser component corresponds to the IRD, and the finer may indicate the source region and the influence of deposition. During MIS 3, MIS 2 and MIS 1, the sedimentation rates of core P31 are 2.2 cm/ka, 0.16 cm/ka and 1.6 cm/ka, respectively. The average sedimentation rate is about 1.2 cm/ka. The overall picture of the western Arctic Ocean shows high sedimentation rates in the ice edge, and low sedimentation rates in areas with permanent sea ice cover. High sedimentation rates occur in areas of shallow water depth, and close to the terrigenous source regions, and low sedimentation rates in the high latitude area of Mendeleev-alpha ridge and Canada Basin area.