dimanche 8 septembre 2013

Long term effort to develop capability to drill to the Earth's Mantle

The Integrated Ocean Drilling Program (IODP) is an international marine research program dedicated to advancing scientificunderstanding of Earth by sampling, instrumenting and monitoring subseafloor environments. Through multiple platforms-JOIDES Resolution, Chikyu and Mission-Specific-Platforms-some of the world's preeminent scientists explore the deep biosphere and subseafloor; environmental change; Earth processes and effects; and solid earth cycles and geodynamics; and other themes.

One of the missions will be to drill 6 km (3.7 miles) beneath the seafloor to reach the Earth's mantle -- a 3000 km-thick layer of slowly deforming rock between the crust and the core which makes up the majority of our planet -- and bring back the first ever fresh samples.

They must first find a way to grind their way through ultra-hard rocks with 10 km-long (6.2 miles) drill pipes.

They have already identified three possible locations -- all in the Pacific Ocean -- where the ocean floor was formed at relatively fast spreading mid-ocean ridges, says Teagle.

The hole they will drill will be just 30 cm in width all the way from the ocean floor to inside the mantle -- a monumental engineering feat.

IODP's initial 10-year, $1.5 billion program is supported by two lead agencies, the U.S. National Science Foundation (NSF) and Japan's Ministry of Education, Culture, Sports, Science, and Technology (MEXT).

If Japanese support can be combined with other funding, Teagle says they could start drilling before the end of the decade, making it possible for humans to finally reach the Earth's mantle by the early 2020s.




To get to the mantle scientists will be relying on a purpose-built Japanese deep-sea drilling vessel called Chikyu, first launched in 2002 and capable of carrying 10 km of drilling pipes. It has already set a world-record for the deepest hole in scientific ocean drilling history, reaching 2.2 km into the seafloor.

What makes the task even more difficult is that, currently, the drill bits have a limited lifespan of between 50-60 hours before needing to be replaced, meaning drilling could take many years unless technology improves.





POSTED BY BRIAN WANG AT 9/08/2013 

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