Japanese and British scientists are exploring the possibility of reaching to the Earth’s mantle, writes NewScientist. The data obtained by researchers will be able to change perceptions about the structure of Earth, as well as provide a new perspective on the complex processes that occur at a depth of 70 km. The site selected for study is the rift created by the March 2011 Tsunami earthquake in Japan.
The project, dubbed as Mohole to Mantle, envisages the creation of underwater wells, using special rigs. The researchers will use deep-sea drilling vessel “Chikyu”. To date, one of the major problems in the implementation of such a project has been funding.
Although the mantle accounts for 68% of the mass of the Earth, very little is known about it.
Damon Teagle from the UK’s National Oceanography Centre in Southampton, who is part of the international team working on the Japanese-led project says that no pristine mantle samples are available at present, and they just have litlle hints of what can be there.
So far nobody has been able to pass over a third of the way to the mantle. Record is a 1507-meter well on the coast of Costa Rica. This is not the deepest hole (even in the oceanic crust), but at this place, scientists have been closest to the mantle: thickness of the crust there is only 5.5 km.
The new project will make the drilling equipment, which is yet to arrive the drawing board. Concern is not only the length but also about the material of drill.
It must be noted that while drilling holes with diameter 30 cm in solid igneous rocks at a speed of 1 m / h, the head of drill survives only for about 50 hours. And the teeth can grind-off even faster.
New superhard material must also withstand a pressure of 2 kbar and temperatures up to 250 degree Celsius. A report, released in 2011 by the company Blade Energy has maintained that the project is technically feasible.
There remains only the problem of financing. According to various estimates, only the working of the vessel requires $ 1 billion. However, the Government of Japan has agreed to bear the lion’s share of costs, other countries have also expressed interest in the project. If all the financial matters are resolved in the next year, scientists hope to reach the mantle within a decade.
The first core – a sample of rock – which is also the last one till date was obtained from the depth of 183 meters in the Pacific Island of Guadalupe in 1961.
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