Correlation between the magnetic susceptibility record of the Chinese aeolian sequences and the marine benthic oxygen isotope record

Abstract

It has been long known that the magnetic susceptibility record of the Chinese loess correlates well with the marine benthic oxygen isotope record at the orbital bands during the last ∼0.8 Ma, suggesting that at the orbital scale, the phasing and periodicity of the East Asian Summer Monsoon (EASM) are controlled by northern ice volume but not by northern summer insolation. However, during the interval ∼2.8–0.8 Ma, there is poor correlation between the EASM record obtained from loess magnetic susceptibility and the global ice volume record obtained from marine benthic oxygen isotopes, arguing against control of the phasing and periodicity of the EASM by global ice volume. Here we show that during the interval ∼2.8–0.8 Ma the magnetic susceptibility record of the Chinese loess correlates well with the clipped and smoothed marine benthic oxygen isotope record from the Eastern Equatorial Pacific Ocean. The data thus suggest that the orbital‐scale periodicity and phasing of the EASM are controlled by northern ice sheets during the entire ∼2.8 Ma, not just the last ∼0.8 Ma. We have shown that tectonic events during the Pliocene are the most plausible causes for the lack of correlation between the Chinese red clay magnetic susceptibility record and the marine benthic oxygen isotope record during the interval ∼4.5–2.7 Ma. We have also shown that the correlation between Chinese red clay magnetic susceptibility record and benthic oxygen isotope record between ∼6 and ∼4.5 Ma is remarkable. The work reported here is complementary to our previous work and indicate that the magnetic susceptibility record of the entire aeolian sequence on the Chinese loess plateau can be correlated with the marine benthic oxygen isotope record.