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沉积物记录的地磁场强度首先提供了模拟地磁场演化的数据约束,其次提供了沉积物的年龄信息.本文报道了菲律宾海西北部岩芯记录的地磁场相对强度,并结合岩石磁学和沉积学性质探讨了影响强度的各个因素.除底部红粘土层的局部磁偏角偏转可能揭示了沉积后改造以外,磁化率各向异性和地磁场方向特征表明沉积物为原状沉积.岩石磁学性质表明沉积物符合磁性均一性,可以记录可靠的地磁场强度.由于红粘土层及其下部的磁偏角异常,本文讨论其上部约125ka的结果.常规归一方法获得的两个地磁场强度参数NRM/ARM(特征剩磁和非磁滞剩磁比值)和NRM/κ(特征剩磁和磁化率比值)与其它记录对比得到时间-深度对比点,对比点之间的年龄为线性内推或者外推.地磁场强度时间模型上的岩芯氧同位素与全球氧同位素综合曲线一致证明强度结果的有效性和对比的正确性.磁化率为归一参数的强度大多低于以非磁滞剩磁为归一参数的强度,频谱和相关分析证明NRM/ARM不与ARM和磁性矿物粒度(ARM/κ)相关,也没有轨道周期性,而NRM/κ却与κ和ARM/κ相关,而且有13～12ka的周期.由此我们认为NRM/ARM记录的地磁场强度比NRM/κ更好地消除了气候印记.进一步探讨了超顺磁含量、碳酸钙含量、磁性矿物组成以及磁性矿物粒度变化与地磁场强度差值的关系,发现末次间冰期较高的超顺磁含量和磁性矿物粒度的较大范围变化造成了地磁场强度差值,后者至少造成了90%差异.中等含量的碳酸钙和较小的磁性矿物组成变化不是磁场强度差值产生的原因.如何校正磁性矿物粒度变化的影响将是下一步工作的重点.
The intensity of geomagnetic field recorded by sediments firstly provides the data constraint that simulates the evolution of geomagnetic field and secondly provides the age information of sediments.This paper reports the relative strength of geomagnetic field recorded by the cores in the northwestern Sea Hercynian and combines with the lithology and sedimentation In addition to the post-depositional remodeling, the magnetic susceptibility anisotropy and the direction of geomagnetic field indicate that the sediment is undisturbed. The magnetic properties of the rock Which indicates that the sediments are in accordance with the magnetic homogeneity and can record the reliable geomagnetic field intensity.According to the abnormal magnetic declination of the red clay layer and its lower part, the results of the upper part about 125ka are discussed in this paper. Two geomagnetic field strength parameters obtained by the conventional normalization method NRM / ARM (feature remanence and non-hysteresis remanence ratio) and NRM / κ (feature remanence and susceptibility ratio) were compared with other records to obtain the time-depth comparison point, the age between the contrast points was linearly interpolated or Extrapolation The consistency of the core oxygen isotope and the global oxygen isotope curve on the geomagnetic field intensity time model proves the validity of the intensity result and the correctness of the comparison. The intensity of the normalized parameter is mostly lower than that of the non-hysteresis remake. The spectral and correlation analysis show that NRM / ARM is not related to ARM and magnetic mineral particle size (ARM / κ), nor to periodic orbit periodicity , While NRM / κ is related to κ and ARM / κ and has a period of 13 ~ 12ka, so we think that the geomagnetic intensity recorded by NRM / ARM can eliminate the climate imprints better than NRM / κ. Paramagnetic content, calcium carbonate content, magnetic mineral composition, and the relationship between the change of magnetic mineral grain size and the difference of geomagnetic field intensity, it is found that the higher range of super-paramagnetic content and magnetic mineral grain size in the last interglacial period caused the change of geomagnetic field intensity Difference, the latter at least caused a 90% difference.Cement content of calcium carbonate and small changes in the composition of magnetic minerals is not the difference between the magnetic field strength.How to correct the effect of magnetic mineral particle size changes will be the focus of the next step.