SEDIMENTARY CHARACTERISTICS OF CORAL REEFS IN THE NORTHERN PART OF THE SOUTH CHINA SEA* BY

In the northern part of the South China Sea there is a complete range of modern coral-reef types, including fringing reefs, barrier reefs, table reefs and at01 Is ( Fig. 1 The distribution of these coral reefs is controlled e i ther by terrigenous sedimentation, or by climatic and hydrodynamic conditions. Because of the interference of terrigenous sediments from the Pearl River and other small rivers, fringing and barrier reefs are mainly limited to the Guangdong shelf around Hainan and Weizhou Islands and in some estuaries, such as the estuary Daya near Hong Kong (Wang Guozhong e_t a_l 1979, Lu Bingquan e_t a_l 1983, 1984). Fringing reefs are absent along most of the coastlines of this continental shelf. Table reefs and atolls are developing off the Xisha Islands area, consisting of more than 30 shoals, banks, islets and islands which cap a submarine platform on the continental slope. Over 1251 m of reef-derived carbonate sediments have accumulated in this area since the Miocene epoch (Fig. 2, Wang Congyou 1979). The northern area of the South China Sea falls within the tropica