No apparent lock-in depth of the Laschamp geomagnetic excursion: Evidence from the Malan loess

摘要

The first-order chronological framework of the long-term Chinese loess/paleosol sequences was based mainly on magnetostratigraphy. However, there remain arguments on the lock-in ages of the major geomagnetic reversals. This study systematically compared the stratigraphic locations of the Laschamp excursion and Henrich events (H4 at ～ 39 ka and H5 at ～ 48 ka) recorded by the Luochuan loess profile in the central Chinese Loess Plateau. Results show that the Lascchamp excursion is bracketed well by these two cold events, and the corresponding estimated age is between about 41.7 - 43.7 ka, which is close to the widely accepted age of ～ 40-41 ka for the excursion. Therefore, our new results do not suggest apparent lock-in effects in the last glacial Malan loess.