797 / 2024-09-19 14:15:45

Luminescence chronology of coastal sand dunes in the northeastern South China Sea and its paleoenvironmental implications

coastal sand dunes, South China Sea, luminescence dating, Red Old Sand, paleoenvironmental change.

Session 27 - Coastal environment evolution : from the past to the future

Coastal sand dunes are crucial sedimentary archives in coastal regions, providing valuable insights into past climate and environmental change, as well as landscape evolution. The Lufeng-Huilai area preserves one of the most comprehensive sequences of late Quaternary sand dunes in the north coastal South China Sea, but the chronologies of these dunes were poorly established. In this study, we presented quartz optically stimulated luminescence (OSL) dating results of 22 samples from two drilled cores and five profiles in the Lufeng-Huilai area. Three samples LFMY2-1, LFMY2-5, and LFMY3-1 from two semi-cemented, strongly weathered reddish sand (i.e., Old Red Sand) dune profiles (i.e., LFMY2 and LFMY3) yielded minimum ages of 169±22 ka, 109±10 ka and 66±4 ka, respectively, due to OSL signal saturation. Nineteen OSL ages from the other three profiles (LFMY1, LFMY4 and GDSH) and 2 drilled dune cores (LFZK5 and LFZK7) fell into the Holocene (~11.7–0 ka). These ages, together with previously published data from coastal sand dunes in southeastern China, revealed three major periods of sand dune accumulation: ~11–5.5 ka, ~4–2.5 ka and ~1.5–0 ka. Multiple factors including sea level fluctuation, detrital sediment supply change in river basins and rice cultivation development along coastal regions may have played distinct roles in sand dune accumulation processes along the southeast coast of China.