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对黄土高原东南部三门峡地区宋家店黄土剖面L8～S12段详细的磁性地层学和岩石磁学研究表明:Matuyama/Brunhes(M/B)界线位于L8黄土层的底部,Jaramillo极性亚时的顶、底界线分别位于L10的中部和L12的底部.黄土和古土壤地层的磁组构保持了原生沉积组构的特点,所记录的剩磁没有遭受到明显的后期扰动.在L9黄土层中记录了2次地磁场异常,认为由重磁化的可能性较小,而磁极性漂移事件的解释更为合理.推算它们的年龄分别与Kamikatsura(0.886Ma)和Santa Rosa(0.922Ma)地磁漂移事件接近,相对古强度研究结果显示,上述地磁漂移事件期间地球磁场强度减弱.
The detailed magnetic stratigraphy and rock magnetism study of L8 ~ S12 section of Songjiadian loess section in the Sanmenxia area southeast of the Loess Plateau show that the boundary of Matuyama / Brunhes (M / B) is located at the bottom of the L8 loess layer, while the Jaramillo polar sub-horizon The top and bottom boundaries are located in the middle of L10 and the bottom of L12, respectively.The magnetic structure of the loess and palaeostolith maintains the characteristics of the primary sedimentary fabric and the recorded remanence has not been subjected to obvious late perturbation.In the L9 loess Two earth magnetic anomalies were recorded, and it is considered that it is less likely to be re-magnetized and the interpretation of magnetic polar drift events is more reasonable. The age of the geomagnetic anomalies is estimated to be related to the geomagnetic drift events of Kamikatsura (0.886Ma) and Santa Rosa (0.922Ma) Close to the relative ancient strength research results show that the earth’s magnetic field intensity weakened during the above geomagnetic drift event.