Climate Dynamics (1996) 12:701-709

Abstract. Three loess sections in the Loess Plateau of China have been studied to characterize the variations of the East Asian monsoon climate in the Late Quater-nary period. Paleo-weathering profiles based on two weathering indices reveal a series of spatially correla-tive intervals of lower weathering intensity (LW), in the last glacial and late penultimate glacial loess, indi-cating significantly cooler or/and drier conditions. Most of them are identified at or near the transitional boundaries between loess and soil units, suggesting that climatic conditions favorable for LW events tended to occur at or near major climatic boundaries. Twenty-eight radiocarbon and thermoluminescence measurements, combined with Kuklas magnetic sus-ceptibility age model date these events at- 14,- 21,-29,-38,-52,-71,- 135, and- 145 ka BP, with- 5-10 ka frequency inlaid within the orbitally induced-20-ka periodicity. The ages of the first six events in the last glacial period are therefore close to those of the coarse-grained Heinrich layers in the North Atlan-tic Ocean, which resulted from massive discharges of icebergs. The results indicate that the climate in the area affected by the East Asian monsoon has experi-enced high-frequency changes more or less synchron-ous with the Heinrich events. These high-frequency changes have been reported by Porter and An, based on the grain-size time series from the Luochuan loess section. Our data also reveal that similar events also occurred during the penultimate glaciation. The mech-anisms linking the Heinrich events and the East Asian monsoon climate may be similar to that driving the Younger Dryas event which has been identified in a large number of records in China and in the surround-ing oceans. Correspondence to: Z. T. Guo