Comparison of paleoclimatic change from Zr/Rb ratios in Chinese loess with marine isotope records over the 2.6-1.2 Ma BP interval

The loess-paleosol sequences in north China act as a key archive in the study of continental paleoclimatic change over the last 2.6 Ma. However, the correlation between the continental loess records and the marine sediments over the 2.6-1.2 Ma BP interval is poorly studied. In this paper, Zr and Rb concentrations were measured on samples taken at 20 cm intervals from the Lingtai section over the interval from 2.6-1.2 Ma BP. Because Zr is enriched in coarse grain fractions whereas Rb is enriched in the fine fractions which are retained during loess pedogenesis, the Zr/Rb in loess can reflect the original grain size variation and serve as a proxy for winter monsoon strength. Our Zr/Rb ratios over the interval from 2.6-1.2 Ma BP generally match the marine delta(18)O record, especially during the 1.9-1.2 Ma BP interval. Strong 400 ka periodicity cycles found in the loess Zr/Rb ratio record are similar to the marine delta(13)C record, suggesting a possible low latitude influence on the paleoclimatic regime during this interval.