Abstract The strong glacial–interglacial similarity between the magnetic susceptibility (MS) of Southern Ocean sediments and Antarctic ice core dust records has often been used to reconstruct Southern Hemisphere atmospheric variability. Although evaluation of various magnetic properties is essential for identifying the magnetic carriers linked to sedimentological variation, detailed magnetic studies are not sufficient in the Scotia Sea. Here we investigate the bulk and particle-size dependent magnetic properties of Scotia Sea sediments over the past ~22 kyr, to determine the main sediment transport mechanism driving bulk magnetic proxies including MS. In bulk sediments, MS is highest during the last glacial period and is accompanied by an increase in the concentration and grain size of ferrimagnetic and antiferromagnetic minerals. For magnetic mineral assemblages, coarse detrital magnetite is dominant. Of three particle-size fractions (>63, 16–63, and 63 μm) throughout the last deglaciation, indicating a close linkage between their input mechanisms. Thus, the sediment particles ranging from sand to coarse silt, which control the bulk glacial magnetic proxies, are most plausibly transported by iceberg-rafted debris (IRD). As hematite is relatively concentrated in the sand fraction, the hematite contribution in the bulk sediment can highlight IRD-related magnetic signals rather than magnetite. The bulk hematite contribution simultaneously varies with the deglacial influx of coarse IRD particles (>1 mm) in Scotia Sea sediments, although their glacial inconsistency possibly suggests a different IRD input mechanism during the advancement and retreat of the ice sheet. Consequently, the glacial increase in the bulk magnetic concentration indicates vigorous iceberg calving activity in the Scotia Sea and further suggests the coupled cryosphere–atmosphere system.

中文翻译：

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自末次盛冰期以来斯科舍海沉积物的粒度相关磁特性：冰川冰盖放电控制磁代理

摘要 南大洋沉积物磁化率 (MS) 与南极冰芯尘埃记录之间强烈的冰期-间冰期相似性经常被用来重建南半球大气变率。尽管评估各种磁性对于识别与沉积学变化相关的磁性载体至关重要，但在斯科舍海进行详细的磁性研究还不够。在这里，我们研究了过去~22 kyr 的斯科舍海沉积物的体积和粒度相关的磁性，以确定驱动包括 MS 在内的大量磁性代理的主要沉积物输送机制。在大块沉积物中，MS 在末次冰期最高，并且伴随着亚铁磁性和反铁磁性矿物的浓度和粒度的增加。对于磁性矿物组合，粗碎屑磁铁矿占主导地位。在整个最后一次冰消期间的三个粒度部分（> 63、16-63 和 63 μm），表明它们的输入机制之间存在密切联系。因此，控制大量冰川磁性代理的从沙子到粗粉砂的沉积物颗粒最有可能由冰山漂流碎片 (IRD) 运输。由于赤铁矿相对集中在沙子部分，大量沉积物中的赤铁矿贡献可以突出与 IRD 相关的磁信号，而不是磁铁矿。大量赤铁矿的贡献同时随着斯科舍海沉积物中粗 IRD 颗粒（> 1 mm）的冰消期流入而变化，尽管它们的冰川不一致可能表明在冰盖前进和后退过程中存在不同的 IRD 输入机制。