BBC, 4 July 2011 Japanese researchers say they have discovered vast deposits of rare earth minerals, used in many hi-tech appliances, in the seabed.

The geologists estimate that there are about a 100bn tons of the rare elements in the mud of the Pacific Ocean floor.

At present, China produces 97% of the world's rare earth metals.

Analysts say the Pacific discovery could challenge China's dominance, if recovering the minerals from the seabed proves commercially viable.

The British journal Nature Geoscience reported that a team of scientists led by Yasuhiro Kato, an associate professor of earth science at the University of Tokyo, found the minerals in sea mud at 78 locations.

"The deposits have a heavy concentration of rare earths. Just one square kilometre (0.4 square mile) of deposits will be able to provide one-fifth of the current global annual consumption," said Yasuhiro Kato, an associate professor of earth science at the University of Tokyo.

The minerals were found at depths of 3,500 to 6,000 metres (11,500-20,000 ft) below the ocean surface.