Climate change and the depositional velocity in the lagoon of Yongshu Atoll, Nansha Islands

The core of Nanyong-3 Well in the Yongshu Atoll is a highly distinguishable sediment pillar of an atoll lagoon available in an undamaged state for the first time in China. The well is 5.90 m deep, in which there are all loose organic detritus. Depositional velocity is calculated according to the ages dated by the highly precise TIMS U system. The mean depositional velocity of the pillar in the last 1682 years of late Holocene was 3.5 mm/a, higher than that (1.21 mm /a) of reef flat of Yongshu Atoll at the same time. these are good materials for highly distinguishable research of palaeo-environment. The whole pillar is divided into 4 alternative parts. The division is generally in accordance with the fluctuation of the air temperature and the change of the cold and warm period in the last 1700 years in mainland China, showing the responds of the Nansha Islands region to the historic climate change of China, even the world.