Introduction of Xisha Islands

Xisha Islands is one of the four islands in the South China Sea of China, which consists of Yongle Islands and Xuande Islands. It is the largest archipelago in the South China Sea of China, starting from the northern suburb in the north, reaching Xianfeng Beach in the south, Xidutan in the east and Zhongjian Island in the west. It belongs to Xisha District, Sansha City, Hainan Province.

Xisha Islands are located between Chinese mainland, dongsha islands and Hainan Island, and between Zhongsha and Nansha Islands. It is the South China Sea waterway hub for exchanges between China and the countries along the Nanyang Islands, Indochina Peninsula and the Indian Ocean. The administrative center of Sansha City is located in Yongxing Island, Xisha Islands.

Xisha Islands are distributed in the sea area of more than 500,000 square kilometers. There are 22 islands, 7 sandbars, 8 atolls, 1 platform reef and 1 reef beach, with a total land area of about 10 square kilometers and a coastline of 5 18 kilometers. Among them, Yongxing Island is the largest, accounting for 3.2 square kilometers (including Shidao), Shidao Island is the highest, with an altitude of 15.9 meters. The Gaojianshi in Dongdao Atoll is the only volcanic breccia island in the South China Sea.

submarine geomorphy

Xisha Islands is located on the stepped continental slope in the southeast of Hainan Island, and is located on an isolated step that is strongly cut by the sea valley. The Xisha Islands are surrounded by troughs and valleys, among which a large-scale arc trough and valley surrounds the western, northern and eastern parts of the island and strongly cuts the continental slope. The valley was filled with sediments and developed into a trough, which was called the Xisha North Sea Trough.

The total length of the trough is more than 460 kilometers, and the west section extends in northeast-southwest direction, and the water depth exceeds 1650 meters. The east is distributed in the east-west direction, with a water depth of more than 3000 meters, from which it flows into the deep-sea plain of the South China Sea. There is a NE seaward trough between Xisha Islands and zhongsha islands-Xisha East China Sea Trough with a depth of 2500m.

The northeast and southwest ends of the trough are less than 3000 meters deep, which is connected with the deep-sea plain of the South China Sea. The southwest edge of Xisha Islands is an inconspicuous northwest seaward trough with a depth of 1 100 meters. Its northwest end is connected with the North Sea Trough of Xisha Islands, and its southeast end extends to the deep-sea plain of South China Sea. To sum up, the Xisha Islands sea area is actually an isolated step, surrounded by an annular depression connected by a trough, which is an isolated block divided by the strong cutting of the continental slope by the trough.

The above contents refer to Baidu Encyclopedia-Xisha Islands.