Cultural relics are salvaged by Chinese research vessels Explore 1 Photo: VCG

 Chinese research vessels Explore 1 and Explore 2 have discovered 66 ancient relics among the wreckage of three ships in the north area of the South China Sea, the Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences recently revealed.

The newly discovered relics include porcelain fragments, redware pottery and bronze coins. The treasures were found on the seabed among three shipwrecks located 2,000 to 3,000 meters below the surface.  

This  depth marks a new deep sea milestone for China's underwater archaeology as the previous record for an underwater excavation by Chinese archeologists was 1,000 meters below the surface. 

"This puts us on the same level as other countries that are advanced in the field of underwater archaeology. There are really not that many countries in the world that can carry out such deep sea archaeology," Cui Yong, head of the team that excavated the famous Song Dynasty (960-1279) Nanhai No.1 shipwreck in the South China Sea, told media. 

Unmanned deep submersible technology was a significant advancement introduced to assist in the latest underwater investigation. 

The submersible is capable of using sonar to locate objects as small as a grain of rice and can cover an area of around 100 square kilometers a day. 

Manned deep dives were also carried out for the underwater identification and extraction of relics after the unmanned submersible located possible relic sites.  

After the excavation of the 66 relics, researchers have continued carrying out further investigations using technologies such as image data extraction and three-dimensional laser scanning. 

"A complete work flow for deep sea archaeological investigations has been established," Deng Qijiang, deputy director of the Institute of Underwater Archaeology of State Administration of Cultural Heritage, told media. 

As the ancient Maritime Silk Road passed through its waters, the South China Sea holds an abundance of historical treasures beneath its surface. 

The Nanhai No.1 was a large merchant ship from the Song Dynasty that remained hidden for more than 800 years under the water in the South China Sea. It was a typical representative of the merchant ships that sailed the seas at the time. 

The shipwreck was excavated in 2007 using China's creative "one-time integrated salvage" solution. 

More than 180,000 fragments of porcelain wares along with 181 gold ornaments were found at the site of the ancient shipwreck.