Characteristics of a relative paleointensity record from loess deposits in arid central Asia and chronological implications

Abstract Loess-paleosol sequences in the arid central Asia (ACA) provide valuable material for evaluating the evolution of paleoclimate and dust circulation in the Northern Hemisphere. However, determination of loess chronology has yet remained a main obstacle for paleoclimate interpretation. In this study, analyses of relative paleomagnetic intensity (RPI) were conducted in a loess section on the northern piedmont of the Tianshan Mountains covering the period since the last interglacial. The RPI record was found to be generally comparable with other recognized RPI stacks, confirming a globally consistent variation of the geomagnetic dipole field. Based on the RPI age model, the attempt to achieve paleoclimate assessment gives rise to largely similar variations to the North Atlantic records. Consequently, these results suggest that the RPI correlation could serve as a promising way to evaluate the age control of loess in the ACA. Nevertheless, in consideration of the complicated topography and loess deposition very close to the dust source, four main factors including carbon contamination, the reliability of luminescence signals, in situ depositional processes and complexity of remanence acquisition, may possibly contort the chronological determination in the ACA loess. Thus, cautions are still indispensable for paleoclimate interpretation with any solely chronological model and more work is therefore required to achieve a comprehensive understanding of loess chronological setting in this area.