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Palomar

Member

From: USA

Registered: 2002-05-30

Posts: 9,734

Re: Is the Moho Rising? - (Drilling into Earth's Crust)

http://www.livescience.com/technology/0 … html]Click

*Interesting.  I'm not familiar with this. 

Scientist said this week they had drilled into the lower section of Earth's crust for the first time and were poised to break through to the mantle in coming years.

...seeks the elusive "Moho," a boundary formally known as the Mohorovicic discontinuity. It marks the division between Earth's brittle outer crust and the hotter, softer mantle.

Says the depth of the Moho varies.  Includes a map regarding crust thickness variations.  They've already drilled 4,644 feet.

--Cindy

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We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,017

Re: Is the Moho Rising? - (Drilling into Earth's Crust)

Did not think much about the distance as being that great until I read the part where it was the ocean floor where they had been drilling.
The only danger is if they should punch though to a magma pocket.
But then again, they could strike it rich and find oil or other gas pockets as well.

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,017

Re: Is the Moho Rising? - (Drilling into Earth's Crust)

Another version of the link above:
Drilling Vessel Recovers Rocks From Earth's Crust Far Below Seafloor

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

The "Moho" is the boundary between the crust and the mantle in the earth. This is a depth where seismic waves change velocity and there is also a change in chemical composition. Also termed the Mohorovicic' discontinuity after the Croatian seismologist Andrija Mohorovicic' (1857-1936) who discovered it. The boundary is between 25 and 60 km deep beneath the continents and between 5 and 8 km deep beneath the ocean floor.

Where the plates are spreading appart:

Scientists aboard two consecutive oceanographic cruises, known as Legs 304 and 305, drilled into the Atlantis Massif, located at the intersection between the Mid-Atlantic Ridge and the Atlantis fracture zone.