Weizhou Island (simplified Chinese: 涠洲岛; traditional Chinese: 潿洲島; pinyin: Wéizhōu Dǎo) is a Chinese island in the Gulf of Tonkin. The largest island of Guangxi province, Weizhou is west of Leizhou Peninsula, south of Beihai, and east of Vietnam. Administratively, it is part of Weizhou Town, Haicheng District of Beihai City.Area: 24.74 square kilometres (9.55 square miles)
Annual average temperature: 22.6 °C (72.7 °F)
Precipitation: 1,380 mm (54.33 inches)
Its north-south length is 6.5 kilometres (4.0 miles), east-west 6 kilometres (3.7 miles). The coast is 15.6 kilometres (9.7 miles), with 6 to 10 kilometres (3.7 to 6.2 miles) of sandy beach. Weizhou rises in the south, where Nanwan Port (南灣港; pinyin: nánwān gǎng) is located. Coral reefs have been established around the island.
Weizhou Dao is China's youngest volcanic island. Its origin is probably from a mantle plume that rose 50–32 million years ago, as a result from the collision of the Indian and Eurasian plate. When the plume reached the asthenosphere, it helped to create the South China Sea by the plume's lateral flow. An evidence that the plume still exists is that a lot of basalt has since the Pliocene erupted in the South China Sea and its adjacent areas, for example the Yandunling 烟墩岭) and Yantouling (烟头岭) volcanoes, Leiqiong (雷琼) volcano group, Weizhou Dao and Xieyang Dao.
The mantle below the Weizhou island has an average temperature of 1,661 °C, which is between the corresponding values of the Hawaii hotspot and the Iceland hotspot.
There have been four periods of volcanic activity on the site, the first one occurred in the early Pleistocene, when mainly ash began to erupt from the bottom of the sea.
The second time, between 9–225 million years ago, started with basaltic magma eruptions, and ended with pyroclastic eruptions. This was the time with the heaviest eruptions on Weizhou and Xieyang.
The third time began with large amounts of volcanic bombs and ended with basaltic magma, this was from 200,000 to 15,000 years ago.
The fourth time, from 10,000 to 7,100 years ago, a few intermittent eruptions happened, first mainly with volcanic bombs, and in the end volcanic ash.
Along with smaller Xieyang Island, Weizhou island is a nature reserve named Beihai Weizhoudao Volcano National Geopark to preserve its volcanic features and protect rich local ecosystem engulfing 147 species of migratory and non-migratory birds, including threatened species such as black-faced spoonbills.
Calm and shallow waters around the two islands have shown recoveries in recent years, resulting in support and attract varieties of marine life from coral reefs to megafaunas more increasingly appear such as sea turtles, whale sharks, endangered finless porpoises, several species of dolphins including nationally protected Chinese white dolphins, and bryde's whales. Hepu Dugong National Nature Reserve established in 1992 covers nearby areas and which is the only sanctuary for dugong in China.
From 1869 to 1879, the French built a Gothic-style 15 metre Catholic church in Shengtang Village (盛塘村; pinyin: shèngtáng cūn), Weizhou. Weizhou Chengzai Church (城仔教堂) was built in 1880, also by French Catholics.