Causation of barrier reefs of the Sekisei Lagoon and fringing reefs of the southern Okinawa Island in the southern Ryukyu Islands on island shelf on the basis of drilling and shallow reflection investigation

冲绳岛南部古石场海岸的全新世珊瑚礁开始在距今约7600年前15~20m的平面上向上生长。古石厂珊瑚礁一期形成于距今约6000年前的隆起区。第二个约4000年前在近海开发，约2500年后在近海形成第三个油气田。Sekiei泻湖全新世珊瑚礁开始在20~25m深的平面上向上生长。在石垣岛南部，大约7000~6000年前，由于隆升运动，形成了第一期珊瑚礁。距今约5500~5000年，竹尾岛发育了一种边缘生物礁，在塞基塞湖内侧形成了点状生物礁。距今约3600年，塞基塞湖外围形成了堰塞礁。由于隆升运动和海平面变化，在这些地区形成了三期全新世珊瑚礁。

Holocene coral reef in Gushichan coast in the southern Okinawa Island commenced to grow upward on the flat surface about 15〜20 m deep about 7600 yrs BP. The first phase of coral reef in Gushichan formed about 6000 yrs BP due to uplifted area. The second one was developed offshore about 4000 yrs BP, then after about 2500 yrs BP the third one was formed offshore. Holocene coral reef in the Sekisei Lagoon started to grow upward on the flat surface about 20〜25 m deep. In the southern Ishigaki Island, the first phase of coral reef was formed about 7000〜6000 yrs BP due to uplift movement. About 5500〜5000 yrs BP, a fringing reef developed in Taketomi Island and patch reef was formed in the inner part of the Sekisei Lagoon. Then about 3600 yrs BP, barrier reef was formed in the outer part of the Sekisei Lagoon. Three phases of Holocene coral reef have been formed in these areas due to uplift movement and sea-level change.