IDENTIFYING THE ORIGIN OF THE MAGNETIC DIRECTIONAL ANOMALIES RECORDED IN THE DATONG LOESS PROFILE, NORTHEASTERN CHINESE LOESS PLATEAU

Abstract

To better understand the origin of short-term features of palaeomagnetic signals recorded by the Chinese loess, detailed palaeomagnetic and magnetic fabric studies were conducted on a loess profile at Datong, the northeastern margin of the loess plateau, which is characterized by both high sedimentation rate (~18 cm ka-1) and variations of sedimentary environments. It appears that the magnetic fabrics, specifically the inclination of the maximum magnetic susceptibility principal axis (K1-Inc), are robust means to identify the deposition environments. Our results (<~74 ka) record four palaeodirectional anomalies (referred as A-D). Among them, anomaly C with relatively normal fabrics can be correlated to the Laschamp (~40 ka) excursion. In contrast, anomalies A, B and D accompanying with K1-Inc anomalies, are interpreted to be caused by post-depositional disturbances. The new results improve our understanding of the origins of the natural remanent magnetization recorded by the Chinese loess. © 2006 The Authors Journal compilation © 2006 RAS.