Ship being built to dig far into Earth's mantle

China is developing an advanced scientific drilling ship capable of reaching about 10 kilometers below the seabed that will allow scientists to explore what truly happens in the Earth's mantle.

Professor Wu Lixin, an academician at the Chinese Academy of Sciences and head of the Qingdao National Laboratory for Marine Science and Technology, said the design for the ship－named Dream－is expected to be finalized this year.

If all goes well, the vessel will be launched around 2021, with construction continuing for several years before it can be commissioned due to the outfitting work, he said. He said its service will allow people to fulfill the long-held dream of seeing the mantle and extensively boost the nation's research on geosciences.

Wu said that with a displacement of 35,000 metric tons, the Dream will become the world's third scientific drilling ship in active service after the JOIDES Resolution and Chikyu, both used by the International Ocean Discovery Program, a worldwide scientific endeavor.

The Chinese craft will be able to drill more than 10,000 meters into the ocean floor, and thus will be tasked with conducting seafloor drilling for geological research as well as surveying and recovering methane clathrate, also known as natural gas hydrate or fire ice, Wu said.

"We have learned a great deal about outer space but still know little about our own planet because scientists have never been able to pierce through the crust and reach the mantle layer," he said.

"If the Dream can help us do so, then we will be able to reveal the cause of earthquakes, learn more about the evolutionary history of Earth's structure and its environment, and find new sources of energy, which will consequently help forecast and prevent natural disasters and mitigate energy shortages."

Lying between the crust, Earth's outermost solid shell, and the outer core, the fluid mantle layer is composed mostly of iron and nickel and has a silicate rocky shell with an average thickness of about 2,900 km.

Methane clathrate is widely regarded as a new, promising source of natural gas. It is often trapped in icelike crystals under high pressure in the permafrost or under the seabed.

The deepest a drill has ever reached is 12,262 meters in the 1970s at the Kola Superdeep Borehole, the result of a scientific drilling project by the former Soviet Union on the Kola Peninsula.

The deepest hole drilled into the ocean floor is 2,111 meters below the seafloor off Japan's Shimokita Peninsula in the northwest Pacific Ocean, dug by the Chikyu in 2012.

Wu said that because the continental crust is about 35 km thick on average, whereas oceanic crust is 5 to 6 km thick, seafloor drilling is more likely to penetrate the crust and reach the mantle.