¹⁰Be Indicator for the Matuyama-Gauss Magnetic Polarity Reversal From Chinese Loess

The Matuyama-Gauss (M-G) magnetic polarity reversal is regarded as a fundamental time marker in the stratigraphic division of the Quaternary-Neogene. However, previous paleomagnetic studies have shown that the M-G is mainly recorded in the Chinese loess unit L₃₃—a glacial stage (corresponding to marine isotope stage 104, i.e., MIS 104)—which is asynchronous with the timing recorded in marine sediments. Here, we solve this long-standing debate by exploiting a method to extract reproducible records of paleomagnetic field intensity from Xifeng and Lantian loess profiles with meteoric ¹⁰Be. The results showed that for both loess profiles, the ¹⁰Be-derived M-G boundary is located in paleosol S₃₂ ca. 2,589 ± 3 ka, which corresponds to MIS 103. This is synchronous with that seen in marine sediments, though it is, on average, ∼19 ka younger than the boundary inferred from paleomagnetic measurements from the two profiles, which demonstrates that magnetic overprinting has occurred.