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应用部分非磁滞剩磁(pARM)谱,对山西宁武天池干海湖泊沉积物携带的磁信息研究表明,粗磁铁矿颗粒(MD)是主要载磁矿物颗粒,其pARM谱在低矫顽力区间(AF<20 mT)达到最高值;而细磁铁矿颗粒(PSD-SD)为次要载磁颗粒,其pARM谱在高矫顽力区间(AF>20 mT)稍有突起。但是,剖面三个层位具有不同特征,上层(大约7.3~4.0 ka)的粗磁性矿物颗粒含量最高,下层(大约12.0~13.0 ka)次之,而中层(大约12.0~7.3 ka)相对最低;中层的细磁性颗粒含量最高,下层和上层的细磁性颗粒含量次之。pARM谱分析结果与磁滞曲线测量获得的磁畴结果一致。在较高的交变磁场区间获得的pARM可以有效地压抑粗磁颗粒的信息,进而使细磁颗粒的信号增强。应用pARM谱分析,能有效判别样品中磁性矿物的磁畴状态,有助于沉积物的古气候、岩石磁学和古地磁学研究。
The magnetic information carried by the sediments of Tianchi Lake in Ningwu, Shanxi Province, using some non-hysteresis remanence (pARM) spectra shows that the coarse magnetite particles (MD) (AF <20 mT) reached its highest value; while fine magnetite particles (PSD-SD) were secondary magnetically loaded particles, their pARM spectrum slightly raised in the high coercivity interval (AF> 20 mT). However, the three strata have different characteristics. The content of coarse magnetic minerals in the upper layer (about 7.3 ~ 4.0 ka) is the highest, the lower (about 12.0 ~ 13.0 ka) and the middle (about 12.0 ~ 7.3 ka) The middle of the fine magnetic particles content, the lower and upper magnetic fine particles followed. The result of pARM spectrum analysis is consistent with the result of magnetic domain obtained by hysteresis curve measurement. The pARM obtained at the higher alternating magnetic field can effectively suppress the information of the coarse magnetic particles and further enhance the signal of the fine magnetic particles. The application of pARM spectrum analysis can effectively distinguish the magnetic domain state of the magnetic minerals in the sample and contribute to the paleoclimate, rock magnetism and palaeomagnetic study of the sediments.