极地研究

极地研究 ›› 2011, Vol. 22 ›› Issue (4-English): 215-222.DOI: 10.3724/SP.J.1085.2011.00215

• 研究论文 • 上一篇    下一篇

Late Quaternary terrigenous sedimentation in the western Arctic Ocean as exemplied by a sedimentary record from the Alpha Ridge

  

  • 收稿日期:2011-08-05 修回日期:2011-10-31 出版日期:1961-12-30 发布日期:1961-12-30
  • 基金资助:

    国家重点基础研究发展规划项目;国家自然科学基金重点项目;中国地质调查局项目;中国极地年计划2007-2009

Late Quaternary terrigenous sedimentation in the western Arctic Ocean as exemplied by a sedimentary record from the Alpha Ridge

LIU Weinan1, WANG Rujian1, CHEN Jianfang2, CHENG Zhenbo3, CHEN Zhihua3& SUN Yechen1   

  1. 1State Key Laboratory of Marine Geology, Tongji University;
    2The Second Institute of Oceanography, SOA;
    3The First Institute of Oceanography, SOA
  • Received:2011-08-05 Revised:2011-10-31 Online:1961-12-30 Published:1961-12-30
  • Contact: WANG Rujian

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摘要：

The terrigenous components in sediment core B84A from the Alpha Ridge, western Arctic Ocean have been investigated to reconstruct the late Quaternary history of the Ice Rafted Detritus (IRD) events, variations of the sedimentation, source regions and climate changes. The core stratigraphy is established by a combination of variations in Mn content, color cycles and foraminiferal abundance. The core extends back to Marine Isotope Stage (MIS) 12.The 12 IRD (>250 μm) events in core B84A are identified; they are assumed to mostly occur during the deglacial periods. The Canadian Arctic Archipelago is suggested to be the source region. These IRD events indicate the collapse of Canadian Arctic ice sheet and drastic climate change. The environmental sensitive components in core B84A are in the silt fractions: 4~9 μm and 19~53 μm, which are mainly transported by sea ice rafting and currents. The two fractions vary asymmetrically and provide indications of current strength. In accordance with previous studies surrounding Alpha Ridge region, the average of sedimentation rate in core B84A is about 0.39 cm/ka. Compared to the high sedimentation rate in the marginal area, the sedimentation rate in the central Arctic Ocean is limited by the sea ice cover and related low bioproductivity, and low terrigenous input due to the relatively long distance transportation from the source region.

Abstract:

The terrigenous components in sediment core B84A from the Alpha Ridge, western Arctic Ocean have been investigated to reconstruct the late Quaternary history of the Ice Rafted Detritus (IRD) events, variations of the sedimentation, source regions and climate changes. The core stratigraphy is established by a combination of variations in Mn content, color cycles and foraminiferal abundance. The core extends back to Marine Isotope Stage (MIS) 12.The 12 IRD (>250 μm) events in core B84A are identified; they are assumed to mostly occur during the deglacial periods. The Canadian Arctic Archipelago is suggested to be the source region. These IRD events indicate the collapse of Canadian Arctic ice sheet and drastic climate change. The environmental sensitive components in core B84A are in the silt fractions: 4~9 μm and 19~53 μm, which are mainly transported by sea ice rafting and currents. The two fractions vary asymmetrically and provide indications of current strength. In accordance with previous studies surrounding Alpha Ridge region, the average of sedimentation rate in core B84A is about 0.39 cm/ka. Compared to the high sedimentation rate in the marginal area, the sedimentation rate in the central Arctic Ocean is limited by the sea ice cover and related low bioproductivity, and low terrigenous input due to the relatively long distance transportation from the source region.

Key words: IRD event, terrigenous component, sedimentation rate, Arctic Ocean, Alpha Ridge, Quaternary

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