Geology And Geophysics

Scientists Vow to Drill into Earths Mantle



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French and English scientists Dr. Benoit Ildefonse of the Montpellier University in France and Dr. Damon Teagle of the National Oceanography Center in Southampton, England have announced a bold and dangerous plan to drill through the Earth's crust deep into the unknown: the high-pressure, superheated mantle.

The daring venture has been tried by others in the past, but the attempts ended in failure.

Crack in the World

Some speculate that if the scientists' drilling project is successful, it might create mega-earthquakes or fracture the mantle leading to a Doomsday scenario similar to the one depicted in the 1965 British science-fiction thriller, "Crack in the World."

That hair-raising film told the story of scientists in East Africa boring into the Earth's mantle and accidentally creating a crack that threatens to split the planet in two. Unable to stop the titanic forces they've unleashed, only the birth of a new moon saves the Earth from certain destruction.

But that's only a movie.

In reality, geoscientists assure the public that no such thing could happen, although they admit some dangers do exist.

The mantle

The Earth is constructed in layers. The first layer is the crust, underneath that is the mantle, and beneath that is what most believe is a spinning, molten iron core.

According to planetary scientists, the best way to reach the mantle is by drilling into a deep ocean bed. There the crust is much thinner and affords easier access to the mantle.

While the average thickness of the crust is just under 25 miles, in some areas of the ocean the crust is as little as five miles thick. Yet, drilling through the crust is no easy task as the mantle is composed of unyielding rock. The deeper the drill bit goes, the greater the pressure. At the beginning of the mantle geologists believe the pressure may be as great as 4 million pounds per square foot.

And as the drilling operation pushes farther and farther down into the crust the temperature soars, rising to nearly 600 degrees Fahrenheit.

Some question if the technology even exists to actually bore into the mantle under such extreme conditions.

A slew of engineering problems

Drilling experts agree with geophysicists that such a venture presents a slew of engineering problems, not the least of which requires that the drilling operation must use drills without the traditional "riser"—in gas and oil drilling risers are the pipes that permit venting of superheated and potentially explosive subterranean gases.

Experts contend that to counter the immense forces at such great depths, pressure has to be used to force what's being drilled through up towards the surface. They believe that pumping seawater into the borehole through the drilling pipe might accomplish that.

The entire purpose of the project is to obtain samples of the mantle for study. If none of the mantle can be forced to the surface of the Earth, then the whole venture would be written off as an abject failure.

Worldwide catastrophe

To those that still worry that drilling so deep into the mantle can present the danger of a worldwide catastrophe, geophysicists point out that large volcanoes have ejected pieces of the mantle from the bowels of the Earth for billions of years. The difference here, they argue, is that these samples of the mantle would be pristine and uncorrupted by the explosive discharge that propelled it through the volcanic magma chamber upwards through the main vent.

They shrug off the dangers by arguing the worst that might happen is a new volcano is created.

Almost as difficult as the project itself will be raising the money to fund such a visionary project. Here, the two scientists are rather sanguine. Both agree that the project may not get off the ground—or rather into the ground—until as late as 2018.

Therefore, all those who wish to worry about the safety of the Earth from such an undertaking still have years to wring their collective hands.

And if by some horrible twist of fate their fears are fully realized, well, they can always hope it will all end with the birth of a new moon.

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