A detailed palaeomagnetic record for the last interglacial period
A detailed palaeomagnetic record for the last interglacial period
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DOI：
10.1016/0012-821x(95)00089-u
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发表时间：
1995-07
影响因子：
5.3
通讯作者：
Zheng Hongbo;T. Rolph;J. Shaw;A. Zhisheng
中科院分区：
文献类型：
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作者：
Zheng Hongbo;T. Rolph;J. Shaw;A. Zhisheng
通过对中国中部晚第四纪黄土-古土壤序列的古地磁研究，揭示了S1土壤复合体上部和下部的两次异常地磁场行为，该复合体跨越末次间冰期。磁化率记录与深海氧同位素地层学的比较提供了一个年表，已被用来估计这些事件的年龄和持续时间。年龄较年轻的插曲已被估计为89-75 ka，相当于从挪威格陵兰海和北冰洋的沉积物中识别的地磁事件的年龄。较老的情节与广泛的低相对palaeointensity已被分配到时间间隔130-110 ka。这与所谓的布莱克事件的现有年龄估计一致。与已发表的来自西宁黄土的布莱克事件记录相反，该记录显示了三个几乎完全相反极性的短事件，在当前记录中，布莱克事件由穿过南半球浅纬度的VGP路径中的一个环来表示。虽然这两个事件都发生在土壤复合体S1的同一部分，但两个记录之间的差异意味着环县记录中地磁信号的平滑程度更高。这可能反映了环县的积累率较低，也可能表明该站点的剩磁获取时间常数较大。
A palaeomagnetic investigation of a late Quaternary loess-palaeosol sequence in central China has revealed two episodes of anomalous geomagnetic field behaviour in the lower and upper parts of soil complex S1, which spans the last interglacial interval. Comparison of the magnetic susceptibility record with the deep-sea oxygen isotope stratigraphy provides a chronology which has been used to estimate the age and duration of these episodes. The age of the younger episode has been estimated at 89-75 ka, comparable with the age of a geomagnetic event recognised from sediments in the Norwegian-Greenland Sea and Arctic Ocean. The older episode is associated with a broad low in relative palaeointensity which has been assigned to the time interval 130-110 ka. This is consistent with existing age estimates of the so-called Blake Event. In contrast to a published record of the Blake Event from the loess at Xining, which shows three short episodes of almost full reversed polarity, in the current record the Blake Event is represented by a loop in the VGP path which passes through shallow southern latitudes. Although both episodes occur within the same part of soil complex S1, the difference between the two records implies a greater degree of smoothing of the geomagnetic signal in the Huanxian record. This is probably a reflection of the lower accumulation rate at Huanxian and may also indicate a greater time constant for the remanence aquisition at this site.