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通过西北冰洋阿尔法脊B84A孔中—晚第四纪以来的沉积物颜色旋回,Mn、Ca元素相对含量、颜色反射率、有孔虫丰度、冰筏碎屑(IRD)含量、粒度组分及其敏感性分析的综合研究,建立了B84A孔的地层年代框架,其沉积物被划分为MIS 12～MIS 1的沉积序列。阿尔法脊B84A孔可以识别出12个IRD事件,它们大多出现在冰消期,并认为其源区为加拿大北极群岛地区。这些IRD事件反映了加拿大北极冰盖的崩塌和气候变化。阿尔法脊B84A孔沉积物的环境敏感组分分别为细组分(4～9μm)和粗组分(19～53μm),两者的变化趋势相反,主要由海冰和洋流进行搬运,指示了洋流的强度变化。B84A孔的平均沉积速率约为0.4 cm/ka,与阿尔法脊周围地区沉积速率相近。相比于近岸的高沉积速率,其限制因素主要为大面积海冰覆盖造成的较低的生产力和由于长距离搬运造成的较低的陆源输入量。
Through the color rotation, the relative content of Mn and Ca, the color reflectance, the abundance of foraminifera, the content of IRD and the grain size of the sediments in the middle-late Quaternary of the B84A, The sensitivity analysis of the comprehensive study of the establishment of the B84A hole stratigraphic dating framework, the sediment is divided into MIS 12 ~ MIS 1 deposition sequence. Alfa ridge B84A hole can identify 12 IRD events, most of them occur in the ice period, and that the source area for the Canadian Arctic archipelago area. These IRD events reflect the collapse of the Arctic ice sheet and climate change in Canada. The environmental sensitive components of the sediments in the ridge B84A of the Alpha ridge are fine (4 ~ 9μm) and coarse (19 ~ 53μm), respectively. The trend of the two is opposite, and they are mainly transported by sea ice and ocean currents, The intensity changes. The average deposition rate of B84A pores is about 0.4 cm / ka, which is similar to the deposition rate in the area around the Alpha ridge. The constraints are mainly the lower productivity due to large-area sea ice cover and the lower land-based input due to long-distance handling compared to the high sedimentation rate of the nearshore.