Chinese scientists claim to have identified a large underwater mineral deposit in the western Pacific containing unusually high concentrations of gold and silver.
The discovery was made during an 18-day expedition involving researchers from Tsinghua University, the Qingdao Institute of Marine Geology and Shanghai Jiao Tong University. The team surveyed a high-temperature hydrothermal field in a back-arc basin within China’s exclusive economic zone and identified three large, cone-shaped sulfide mounds.
Preliminary analysis found gold concentrations of up to 0.45 troy ounces (0.4937 ounces) per US short ton of ore, while silver grades reached 36.3 troy ounces (39.83 ounces) per US short ton. Researchers note that the deposit could have significant exploitation potential, although extracting minerals from the deep seabed remains technically difficult and environmentally challenging.
The deposit was found in a hydrothermal field, where extremely hot, mineral-rich fluids rise through cracks in the ocean floor. When these fluids encounter near-freezing seawater, they cool rapidly, causing dissolved metals to precipitate as sulfide minerals.
These deposits, known as seafloor massive sulfides or hydrothermal sulfide deposits, can contain copper, zinc and lead alongside smaller quantities of gold and silver. In this case, however, researchers reported precious-metal concentrations significantly higher than those typically found in terrestrial deposits, the South China Morning Post reported.
Gold concentrations in the newly identified ore reached as much as 0.45 troy ounces per US short ton, while silver reached a maximum of 36.3 troy ounces per US short ton. Song Shiji, vice-dean of the Institute for Ocean Engineering at Tsinghua University and one of the project’s lead scientists, said the newly identified seabed area could have substantial economic value.
The ore is primarily composed of minerals including chalcopyrite, pyrite and sphalerite, which are commonly associated with copper, iron and zinc deposits.
Mapping the area for years
The discovery was made during an expedition aboard the Xiang Yang Hong 10, one of China’s first domestically designed and built large oceanographic research vessels. The ship departed Shenzhen on August 10, with the team conducting seven deep-submergence dives during the mission.
The latest expedition followed more than a dozen earlier surveys of the region. Those missions identified dozens of high-temperature hydrothermal vents at depths between 2,300 and 4,920 feet, with fluid temperatures exceeding 599 degrees Fahrenheit.
Researchers subsequently identified a new and very large hydrothermal mining area within the basin. The precise coordinates have not been disclosed, although Chinese state media said it lies within China’s exclusive economic zone. According to marine tracking data, the research vessel traveled through waters north and east of Taiwan and north of the Philippines during the expedition.
The western Pacific contains extensive hydrothermal activity, with fields stretching across a broad region from the Kuril Islands north of Japan toward waters northeast of New Zealand. That makes the area scientifically important, but also potentially significant for countries interested in accessing seabed mineral resources.