Japan is starting an expedition to reach a place no human has ever witnessed, although we stand firmly above it: the Earth’s mantle.
Japan’s Agency for Marine-Earth Science and Technology (JAMSTEC) plans to drill through 6 kilometers (3.7 miles) of oceanic crust to reach the mantle for the first time. A team of researchers from JAMSTEC will conduct a preliminary study in the waters of Hawaii in September.
There are still issues to be resolved, particularly the cost. However, the preliminary study will be a big step forward for this project to enter a new stage.” Susumu Umino, a professor at Kanazawa University who specializes in petrology, told The Japan News.
The project is estimated to cost $540 million and will be carried out by Chikyu, a flagship Japanese deep-sea drilling vessel. The researchers hope to start the mission in the early 2020s, or by 2030 at the very latest. Two other sites are also being considered, one off the coast of Mexico and one off the coast of Costa Rica. The oceanic crust is much thinner than the continental crust, which is on average around 20 kilometers (12.4 miles).
This newly announced project is just one of many so far unsuccessful attempts at reaching the mantle, with both sea beds and lands drilled. The deepest we have ever got was the Kola Superdeep Borehole, which reached 12,262 meters (over 40,000 feet). Due to lack of fundings, the project and the site were abandoned in 2008.
A mixture of high costs and limited technology has hindered previous missions, but the JAMSTEC team believe the technology is now right to bore through the crust and reach the mantle. What we know of the Earth’s interior was learned indirectly through earthquakes. Even magma from volcanos doesn’t provide pure samples of the mantle, as it’s all mixed up with molten crust. Drilling provides the unique chance to study the composition of the mantle as it truly is. With that, we could hopefully clarify some unclear points of plate tectonics and maybe even understand how our planet formed.