A 1400-year terrigenous dust record on a coral island in south china sea

Abstract

We present analyses of a lacustrine sediment core (DY6) on Dongdao Island, which provides high-resolution paleoclimate records for the South China Sea (SCS). Results of element analyses indicate that the concentrations of Ti and Al in DY6 are much higher than the background on the island. Morphological characteristics of acidic insoluble particles are similar to aeolian in East China. Sr and Nd isotope compositions in these particles are consistent with those in Asian aeolian dust. We inferred that dust in DY6 may have been transported by East Asian Winter Monsoon (EAWM) from inland Asia. The continuous dust records for the past 1400 years in North SCS were presented based on the measured Ti flux, which revealed an opposite trend to the variations in the EAWM for the past 50 years. A comparison of wind fields between cold and warm years shows that north surface wind in southeast China was stronger in cold years. However, 850 hPa wind vector along the east coast of China, the key level of wind for long-distance dust transmission, weakened in cold years. We conclude that differences in the EAWM records can be attributed to the 850 hPa wind pattern in different areas.