China finds large seafloor mineral deposit rich in gold and silver

A joint scientific expedition has made an important breakthrough in its investigation of hydrothermal activity and mineral resources on the western Pacific seafloor.

Researchers from Tsinghua University, the Qingdao Institute of Marine Geology under the China Geological Survey, Shanghai Jiao Tong University and other institutions used domestically developed equipment to identify a large, previously unknown active high-temperature hydrothermal field. Preliminary findings indicate that the area could contain substantial polymetallic sulfide resources.

The research team departed Shenzhen aboard the research vessel Xiang Yang Hong 10 on August 10. During the 18-day expedition, it carried out seven probe dives in a back-arc basin within China's exclusive economic zone in the western Pacific.

Before the latest expedition, the team had conducted more than 10 surveys in the area and identified dozens of high-temperature hydrothermal vents. The vents are located at depths of about 700 to 1,500 meters. Temperatures of end-member fluids at the vents exceeded 315 degrees Celsius, indicating intense hydrothermal activity.

Building on those earlier surveys, the team used detailed mapping and in situ sampling to pinpoint a new and extensive hydrothermal mineral deposit in the basin. The associated hydrothermal sulfide orebody consists of three large cone-shaped structures.

Preliminary analysis in the vessel's onboard laboratory found that the orebody is mainly composed of economically important minerals, including chalcopyrite, pyrite and sphalerite.

Initial tests on selected samples detected associated gold concentrations of up to 15.4 parts per million and silver concentrations of up to 1,271 parts per million. According to the research team, their average concentrations were significantly higher than those commonly found in terrestrial mineral deposits.