马兰黄土中Laschamp地磁漂移的10^Be记录与古地磁测试结果的初步对比

Laschamp地磁场漂移事件发生的确切年代(~42kaBP)已通过相对独立的同位素定年手段确定,并被证实具有全球性特征.但这一事件在我国马兰黄土地层中的记录存在着明显的空间差异.本文初步对比了最近发表的黄土高原洛川剖面mBe4L录的Laschamp漂移信息和前人根据该44面古地磁参数异常结合Heinrich冷事件所确...

10Be evidence for the Laschamp excursion in Malan loess and its preliminary comparison with that of paleogeomagnetic study

The Laschamp geomagnetic excursion event with reliable age of 42 ka BP deriving from the independent isotope dating method, has been proved to exhibit the global nature. However, there exists clear spatial discrepancy of the record for this event in the Malan loess strata in Chinese loess sections. In this paper, the recently published ¹⁰Be tracing study on Laschamp excursion in Luochuan section is preliminarily compared with that of the previous records for this event by the combination analysis of abnormal paleomagnetic parameters with the cold Heinrich events, which further confirms the reliability of this geomagnetic event records in the Malan loess strata. In addition, the preliminary comparison also suggests that there is a offset of 76 cm for the position of Laschamp excursion recording by the abnormal ¹⁰Be production rate with low magnetic field strength and the paleomagnetic anomalies respectively. The geomagnetic results for the Laschamp excursion is downwards shifted compared with that of the ¹⁰Be records. Therefore, the obvious offset for the same geomagnetic event by ¹⁰Be tracing and paleomagnetic measurement is of importance, if the possible effects from sampling resolution difference in two independent studies can be neglected. It may provide a potential way to improve our understandings on the sedimentary remanence acquisition process for Chinese loess-paleosol sequence.