QINGDAO, Shandong, May 29  -- The Chinese research vessel Dayang Yihao (Ocean No. 1) on Thursday returned to its base port in Qingdao City after finishing a 179-day exploration of the Indian Ocean.

According to China Ocean Mineral Resources R & D Association, during the 25,628-nautical mile voyage in China's 30th oceanic expedition mission, researchers on board the vessel collected 14 deep-drilling core samples from the sea bed for polymetallic sulfide research.

The research will lead to an estimate of the amount of mineral resources in the sea bed.

China secured an approval from the International Seabed Authority (ISA) in 2011 to explore a 10,000-square-km polymetallic sulphide ore deposit in an international seabed region in the southwestern part of the Indian Ocean.

Ocean No. 1's mission was the country's first expedition to the area after gaining the approval.

Research aboard the vessel detected 11 new seafloor hydrothermal areas during the trip. The mineral-rich areas often see hydrothermal vents spewing out mineral-enriched fluids.

A 133-member expedition team composed of researchers from 30 Chinese research institutions and universities left from the port city of Sanya in south China's Hainan Province on Dec. 2 last year for the expedition.

During the trip, the team also provided training on marine scientific research for three foreign members sent via the ISA from Cameroon, Thailand and Argentina.