East Asian Winter Monsoon record from the environmental sensitive grain size component of QF Old Red Sand, Haitan Island, China

摘要

The "Old Red Sand" is widely distributed along the coast of Fujian Province, China. Most studies have been carried out from aspects of the origin, age and laterization of the "Old Red Sand", but this paper focused on reconstructing the history of the Asian Winter Monsoon change. On the basis of granulometric analysis of high-resolution samples, we have obtained environmental sensitive grain size component (ESGSC) from the Qingfeng (QF) profile by using the grain size-standard deviation method, which proves that the selected ESGSC is an important climate proxy. The mean grain size of this ESGSC could be used to reconstruct the East Asian Winter Monsoon (EAWM) intensity. As such, the history of the EAWM change since 44.0 ka reconstructed here reveals three main phases based on chronology dates of previous researches: (1) 44.0-25.5 ka B.P., the EAWM is relatively weak but increases gradually with fluctuations; (2) 25.5-15.5 ka B.P., relatively strong with high frequency fluctuations; (3) 15.5-7.1 ka B.P., with a weaker winter monsoon, but during 11-10 ka B.P. is remarkably enhanced. The EAWM recorded by mean grain size of the two neighboring sections have a better repeatability, so the millennial scales oscillation should be a reliable signal of the EAWM intensity. The climate recorded by ESGSC of the QF "Old Red Sand" compared to δ 18 O of Hulu Cave stalagmites and Greenland GISP2 ice cores shows a good consistency, especially in detail, the YD event and four Heinrich events are all recorded, but the signal of D-O cycles was relatively weak.