Millennial-scale variations of sea-ice expansion in the southwestern part of the Okhotsk Sea during the past 120 kyr: Age model and ice-rafted debris in IMAGES Core MD01-2412
Millennial-scale variations of sea-ice expansion in the southwestern part of the Okhotsk Sea during the past 120 kyr: Age model and ice-rafted debris in IMAGES Core MD01-2412
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DOI：
10.1016/j.gloplacha.2006.01.012
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发表时间：
2006-08
影响因子：
3.9
通讯作者：
T. Sakamoto;M. Ikehara;M. Uchida;K. Aoki;Y. Shibata;T. Kanamatsu;N. Harada;K. Iijima;K. Katsuki;H. Asahi;Kozo Takahashi;H. Sakai;H. Kawahata
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文献类型：
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作者：
T. Sakamoto;M. Ikehara;M. Uchida;K. Aoki;Y. Shibata;T. Kanamatsu;N. Harada;K. Iijima;K. Katsuki;H. Asahi;Kozo Takahashi;H. Sakai;H. Kawahata
在鄂霍次克海西南部采集了一个58米长的沉积物岩心INOM MD 01 -2412，用于高分辨率古地理研究。通过浮游有孔虫外壳的加速器质谱（AMS）14 C测年、底栖有孔虫方解石的氧同位素地层学和火山灰年代学获得了岩芯的年龄模型，得出岩芯底部年龄为115 kyr。通过对冰筏碎屑（IRD）的测量，对鄂霍次克海海冰扩展过程进行了重建。西南鄂霍次克海在115 kyr期间没有常年海冰，但有季节性海冰。季节性海冰波动幅度大，千年尺度的冰川（海洋同位素阶段：MIS 2，3，和4）和变化相对较小，在全新世（MIS 1）和末次间冰期（MIS 5）。冰川期间极地大气环流的增强导致鄂霍次克海上空的强风场，并加速了冰川期间海冰的大规模扩张（MIS 2，3和4）。在间冰期（MIS 1和5），海冰也扩大了小幅度。在此期间，阿穆尔河流量的减少将是海冰扩展的可能因素之一。极地大气环流和阿穆尔河排放的两个主要因素将负责在120 kyr海冰扩张。
A 58-m-long sediment core IMAGES MD01-2412 was recovered in the southwestern part of the Okhotsk Sea for high resolution paleocenography. An age model of the core was obtained by accelerator mass spectrometry (AMS)14C dating of planktonic foraminifer shells, oxygen–isotope stratigraphy of benthic foraminifer calcite, and tephrochronology, resulting in a core-bottom age of 115 kyr. Sea-ice expansion in the Okhotsk Sea was reconstructed by ice-rafted debris (IRD) based on measurement of dropstone, coarse fraction, sand fractions of terrigenous particles, and the magnetic properties. The SW Okhotsk Sea has not had perennial but seasonal sea-ice conditions during the 115 kyr. Seasonal sea ice fluctuated with large amplitudes on millennial scale during the glacials (Marine isotope stage: MIS 2, 3, and 4) and varied relatively little during the Holocene (MIS 1) and the last interglacial (MIS 5). Enhanced polar atmospheric circulation during the glacial resulted in strong wind fields over the Okhotsk Sea and accelerated the large sea-ice expansion during the glacials (MIS 2, 3, and 4). During the interglacials (MIS 1 and 5), sea ice also expanded by small amplitudes. During these periods, decrease of the Amur River discharge would be one of the possible factors for sea-ice expansion. The two main factors of polar atmospheric circulation and Amur River discharge would be responsible for sea-ice expansion during 120 kyr.