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以东海内陆架泥质区F17柱样为对象,在放射性同位素测年、磁性测量、地球化学和粒度分析的基础上,探讨了早期成岩作用对陆架沉积物磁性特征的影响。结果表明,F17柱样磁性特征存在显著的垂向变化,表现为随深度的增加,沉积物磁性减弱、磁性颗粒变粗和不完整反铁磁性矿物比例上升。粒度以及Al,Ti,Fe,Mn的含量,有机碳和总硫的分析表明,沉积物物源相对均一,粒度虽然存在垂向变化,但不是磁性特征垂向变化的主要原因,早期成岩作用是导致上述磁性特征垂向变化的主要因素。早期成岩过程中,亚铁磁性矿物含量随深度下降的现象与其他地区报道的结果类似,但磁性矿物类型和颗粒大小随深度变化的模式,不同地区存在一定差异。基于磁性矿物对早期成岩过程的敏感性,磁性测量方法对认识铁在陆架沉积物中的迁移和转化具有积极作用。
Based on the radioisotope dating, magnetic measurements, geochemistry and grain size analysis, the F17 column samples in the muddy area of the East China Sea are used to study the effect of early diagenesis on the magnetic characteristics of the shelf sediments. The results show that there is a significant vertical change in the magnetic characteristics of F17 column, which shows that with the increase of depth, the magnetic properties of the sediments are weakened, the magnetic particles become thicker and the proportion of incomplete antiferromagnetic minerals increases. Particle size, contents of Al, Ti, Fe and Mn, organic carbon and total sulfur show that the source of sediment is relatively uniform. Although the grain size has vertical change, it is not the main reason for the vertical change of magnetic characteristics. The early diagenesis The main factors that lead to the vertical change of the above magnetic characteristics. In the early diagenesis, the phenomenon that the magnetic iron content decreased with depth is similar to that reported in other areas. However, there are some differences in the types and sizes of magnetic minerals with depth in different regions. Based on the sensitivity of magnetic minerals to early diagenesis, magnetic measurements have a positive effect on understanding iron’s transport and transformation in the shelf sediments.