A new correlation between Chinese loess and deep-sea δ18O records since the middle Pleistocene

Abstract

The Quaternary Chinese loess is one of the most continuous terrestrial sediments, and preserves excellent palaeoclimate records at different timescales. The conventional land-ocean palaeoclimatic comparison has been established by correlation between magnetic susceptibility of the Chinese loess and deep-sea δ18O records during the 1980s. However, such a correlation results in long-standing debates on the lock-in depth of the palaeomagnetic polarity boundaries in Chinese loess. In this study, the lock-in depth of palaeomagnetic signals for loess <130 ka were estimated through correlation between palaeomagnetic relative palaeointensity (RPI) and 10Be RPI curves, and are linearly related with the calculated loess dust accumulation rate. Palaeomagnetic displacement for the geomagnetic polarity boundaries and excursions in the middle Pleistocene loess at Luochuan, Zhaojiachuan and Lingtai sections could be estimated using the linear relation only in decimeter scale (generally <50 cm) which indicates paleomagnetic boundaries in Chinese loess can be used as reliable age control points after moderate adjustments. Based on this as well as a high-resolution loess magnetostratigraphy and grain-size sequence, we propose a new scheme for palaeoclimatic correlation between Chinese loess and marine sediments since the middle Pleistocene.