摘要
海南岛周缘分布的珊瑚礁,是陆地边缘围绕基岩海岸和岛屿发育起来的不成熟型岸礁礁体,具有进积序列的沉积相序。不存在堡礁(或堤礁)礁体类型。依据碳、氧稳定同位素和其它地球化学资料,这些珊瑚礁的主体是末次冰期阶段发育起来的,与放射性碳等年代资料相悖。
Coral reef, near the present sea level in Hainan Islnad, is an immature coast reef body, which is located in land edge or offshore island and grows up around basement rock of coast and island. It has the following basic characters:
1. Coral reefs distributed around periphery of Hainan Island have different scales and forms from each other, but identical on their basic sedimentary facies sequence: first reef-front neritic facies, then upwards in turn as reef-front collapsed material, reef frame and reef-flat facies, belonging to a sediment association of progradational sequence.
2. If physical, chemical and climatic conditions are the same, formation of coral reefs is controlled by environmental types. Only erosion or balance environment is favourable for reef development.
3. Either a whole set of reef-facies sediment or a single reef frame is very thin. The thickness of a whole reef facies is generally less than 12m, and a single reef frame not over 1m in thickness.
4. Hainan Island has no barrier reef type. Its so-called lagoonal reef is a remnant rock reef in a lagoon built by a tombolo enclosing a landward open water area.
5. Many parts of coast reef in Hainan Island are covered by modern coastal sediments, so organic reef is forced to accrete laterally.
Hainan corel reef was long considered to be product of Holocene and to have a primary age <9000 a. B. P. According to data of geochemical paramerter and carbon and oxygen stable isotopes, however, its main formation time was during the last glacial period. Holocene coral reefs are only the very thin accretion on the top of reef flats and side reef frames. Some dating data contradict greatly oxygen isotope dating. This adds some complication to coral reef researches to a certain extent. On the other hand, documents about Holocene sea-level changes and Holocene coast uplifting rates of Hainan Island etc. should also be redetermined.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
1990年第2期25-43,共19页
Marine Geology & Quaternary Geology
基金
国家自然科学基金委员会资助项目
