OSL dating of late Holocene coastal sediments and its implication for sea-level eustacy in Hainan Island, Southern China

Since the sea-level rise is not geographically homogeneous but rather shows great regional differences, optically simulated luminescence using quartz as a natural dosimeter has proved to be a powerful and reliable dating technique to determine depositional ages of young coastal sediments around the world. The samples acquired from one beach ridge and two marine terraces in coastal Hainan Island, southern China are detected OSL dating for the investigation of sea-level changes. The results show: (1) coastal sands in Hainan Island were well bleached before deposition, and the quartz OSL can date coastal sediments younger than 200 years, which could be one of good indicators for paleo relative sea-level highstand records; (2) three coastal sediments with 4 m, 3.7 m, and 2 m higher than present sea-level were deposited at 2.40 ± 0.05 ka, 2.92 ± 0.17 ka, and 4.26 ± 0.10 ka, respectively, which indicate that the height of highstand relative sea-level are higher than both mean global sea-level eustacy and those records offshore southern China; (3) Comparisons with tropical cyclones observations around South China Sea indicates that the late Holocene coastal sediments of Hainan Island might have been reformed by tropical cyclones with a highstand sea-level.