Magnetism Signals in a Stalagmite from Southern China and Reconstruction of Paleorainfall During the Interglacial‐glacial Transition

Precipitation variations deduced from speleothem stable oxygen isotopes (delta O-18) have long been debated in monsoonal China. The magnetic property in speleothems is interpreted to be related to regional precipitation and can therefore offer reliable information of regional precipitation variations. Here we present a speleothem from southern China to explore the magnetic signals in speleothems and to reconstruct regional precipitationin hominin-occupational area in southern China during MIS5. Saturation magnetization (M-s), which represents the magnetic mineral concentrations, is used as an indicator of effective rainfall variations. The precipitation inferred from M-s increased sharply in the period prior to 80.3 ka before present, followed by a drop to precipitation anomaly afterward, indicating that regional precipitation varied greatly during the hominin-occupied interval in southern China. Power spectrum analysis of M-s values shows significant similar to 205-, similar to 90-, similar to 77-, and similar to 64-year periodicities, suggesting that the solar activity may play an important role in precipitation variations in southern China during the MIS5a/4 transition.