Islands and reefs in the Zhongsha Islands and their islands in the three Shashi, Hainan Province

Zhongsha Islands and reefs

Zhongsha island reef, formerly known as hongmaoqian, is the largest atoll in the South China Sea. It is completely submerged by sea water, and the water depth is generally 9-26 meters. Most of the sea area of the Zhongsha Islands is located in the central part of the tropics. It is the birthplace of typhoon in South China Sea.

position

The central archipelago among the four islands in the South China Sea of the people's Republic of China.. In ancient times, it was called hongmaoqian. Latitude 15 ° 24 ′～ 16 ° 15 ′ n, longitude 113 ° 40 ′～ 114 ° 57 ′ E. The main part is composed of three submerged sands, shoals, reefs and islands. It is about 140 km long (excluding Huangyan Island) and 60 km wide. It extends from northeast to southwest and is slightly elliptical. It includes Zhongsha atoll on the west side of the South China Sea basin, Shenhu and Yitong sand on the north side, constitutional sand, Zhongnan sand and Huangyan Island (democracy reef) on the deep sea basin. Almost all of them are hidden under the sea, about 10-26 meters away from the sea, only the south of Huangyan Island is exposed. Huangyan island is the only atoll in the Zhongsha Islands, which is the surface of the sea. It is a coral reef overlying the seamounts. It is located on the east side of the middle part of the river. It is about 300 km from the beach, triangular like, about 19 kilometers long, the edge is steep, the lake is clear and green, and the stone plate shaped coral reef is visible on the reef. The highest is called "South rock", which is about 1.8 meters above sea level. Huangyan Island is like a coral rock pillar, standing on the sea from the 4000 meter deep sea basin. Although Zhongsha is a group of dark sand hidden in the water, it is close to the sea surface and has a large area, so it has a great impact on the sea surface. When the weather is bad, such as walking in the dark sand, the wave is very big, the sea near the beach is disturbed by it, and the sea appears high and chaotic. In the sea area where the dark sand is located, the water is slightly green, while the deep sea is blue, which is very easy to distinguish. Therefore, as early as 200 years ago, China and Saudi Arabia were used as a sign of "waigou" for navigation, and the routes from Guangzhou, Hong Kong, Shanghai, Taiwan, Japan and Singapore all passed through it.

the measure of area

Zhongsha atoll is the largest one among the islands in the South China Sea. It is submerged by sea water, and the water depth is generally 9-26 meters. On the east side of the great atoll is a deep and large crustal fault zone. The contact between the continental crust and the oceanic crust has a steep slope of 51 ° to 58 ° and descends to the 4000 m Sea basin. The reef area between the great atoll and the Spratly Islands is the deepest part of the South China Sea (-5559 m). The heat flux, Bouguer gravity and magnetic force are all very high, which may be related to the drift of the continental block. In the Zhongsha Islands, the edge of the sand is not connected with each other, resulting in many independent individuals. The faulted part becomes the natural channel of the lake. Dark sand is also scattered in the lake, among which the shallowest is strolling dark sand, which is only 9 meters.

resources

Zhongsha is an important fishing ground in the South China Sea, which is rich in nutrients and salts. It is rich in many kinds of aquatic products, such as golden snapper, swordfish, swordfish, tuna and so on. The biomass of coral reefs is also high, forming a colorful "undersea garden". Fishermen of the people's Republic of China have been engaged in fishing activities in the Zhongsha sea area for generations. The sovereignty of the Zhongsha Islands belongs to People's Republic of China. In 1984, the Zhongsha Islands reef and sea area were placed under the jurisdiction of the Hainan administrative region. In 1988, Hainan was established and the Zhongsha Islands were classified as Hainan province. The Zhongsha Islands belong to the three Sha City of Hainan province. The Zhongsha Islands are the virtual towns of Zhongsha Islands and reefs.