Huge hole in the earths atlantic crust

Scientist have discovered an area under the atlantic ocean 1000s km wide that appears to have no crust at all? The crust should be over 3 km thick in this region.

Intially it reminded me of the nut case hollow earth theory where there is supposed to be a huge hole at the north pole.

news.bbc.co.uk...

Does anyone know anymore on this - geology etc is not my storng point by a long shot, but this got me interested.

Cheers,

Q

Im no geologist and am very confused.

What exactly is there if the crust is not?
Is it just a massive hole 6-7 kms deep full of water?

Can someone with some expertise shed some light on this please.

Originally posted by Chronic_Blaze
Im no geologist and am very confused.

What exactly is there if the crust is not?
Is it just a massive hole 6-7 kms deep full of water?

Can someone with some expertise shed some light on this please.

well according to this scientist:

As a result, the mantle is exposed to seawater, creating a rock called serpentinite.

Here is info from WIKI on this rockWIKI

Would the water boil? Or is the pressure down there too great to allow that?

Possible site of asteroid impact?

Don't know anything bout this subject!

Odd. Just the other day they find a huge underwater body under China, and now this.

Another source:



The cruise link: JC007: Drilling the Mid-Atlantic Ridge

And a related story from ScienceDaily may shed some light on what's going, or not going, on here:


Great find

Found this story just the other day and was thinking, if this is true then there must be a hole in the crust somewhere. Now I know where.

Giant Slab of Earth's Crust Found Near Core

A huge slab of folded Earth that scientists think used to be part of the ocean floor has been detected near the planet's core.

The discovery supports the theory that Earth's crust is constantly recycled deep into the planet as molten material from below simultaneously pushes up to refresh the surface.

The structure is about 125 miles deep and at least 125 miles wide and 370 miles in the north-south direction. In consistency, it is more like a giant, folding mush of taffy, researchers said today.

"If you imagine cold honey pouring onto a plate, you would see ripples and folds as it piles up and spreads out, and that's what we think we are seeing at the base of the mantle," said Alex Hutko, a graduate student University of California, Santa Cruz and lead author of a paper describing the discovery in the May 18 issue of the journal Nature.

This is the link to the original news source.

www.livescience.com...


Mod Edit: to apply external quote code, please review this link


[edit on 1-3-2007 by DontTreadOnMe]

If ti was something to do with crust being recycled back to the core, I wonder what conditions would need to exist for a huge piece to sink down like that?

Love the theory of meteor impact, but I dont know enough about that side of things to comment sensibly - anyone got any ideas?

Cheers,

Q

Well if it was an asteroid impact, then the missing area would be circular (roughly), and I assume it would also be gently sloping on each side.

Earth's crust appeared to be completely missing in an area thousands of kilometres across.

If this is the case, it makes such an impact event very unlikely, as such an event would probably kill everything and life would have to emerge again. To get an idea of the size of the object needed for a final crater this size, this is what I got:

Your Inputs:
Distance from Impact: 12000.00 km = 7452.00 miles
Projectile Diameter: 80467.00 m = 263931.76 ft = 49.97 miles
Projectile Density: 8000 kg/m3
Impact Velocity: 51.00 km/s = 31.67 miles/s
Impact Angle: 45 degrees
Target Density: 1000 kg/m3
Target Type: Liquid Water of depth 5000.00 meters, over typical rock.

Energy:
Energy before atmospheric entry: 2.84 x 1027 Joules = 6.78 x 1011 MegaTons TNT
The average interval between impacts of this size is longer than the Earth's age.
Such impacts could only occur during the accumulation of the Earth, between 4.5 and 4 billion years ago.

Major Global Changes:
The Earth is not strongly disturbed by the impact and loses negligible mass.
The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
The impact does not shift the Earth's orbit noticeably.

Crater Dimensions:
The crater opened in the water has a diameter of 1160 km = 722 miles

For the crater formed in the seafloor:
Transient Crater Diameter: 706 km = 439 miles
Transient Crater Depth: 250 km = 155 miles

Final Crater Diameter: 1670 km = 1030 miles
Final Crater Depth: 2.76 km = 1.71 miles

The crater formed is a complex crater.
The volume of the target melted or vaporized is 1.74e+07 km3 = 4.16e+06 miles3
Roughly half the melt remains in the crater , where its average thickness is 44.3 km = 27.5 miles

Thermal Radiation:
The fireball is below the horizon. There is no direct thermal radiation.

Seismic Effects:

The major seismic shaking will arrive at approximately 2400 seconds.
Richter Scale Magnitude: 12.5 (This is greater than any earthquake in recorded history)
Mercalli Scale Intensity at a distance of 12000 km:

VI. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.

VII. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.


Ejecta:
Little rocky ejecta reaches this site; fallout is dominated by condensed vapor from the projectile.


Air Blast:

The air blast will arrive at approximately 36400 seconds.
Peak Overpressure: 358000 Pa = 3.58 bars = 50.8 psi
Max wind velocity: 418 m/s = 935 mph
Sound Intensity: 111 dB (May cause ear pain)
Damage Description:


Multistory wall-bearing buildings will collapse.

Wood frame buildings will almost completely collapse.

Multistory steel-framed office-type buildings will suffer extreme frame distortion, incipient collapse.

Highway truss bridges will collapse.

Glass windows will shatter.

Cars and trucks will be overturned and displaced, requiring major repairs.

Up to 90 percent of trees blown down; remainder stripped of branches and leaves.

Source: Impact effects calculator

And as this is near the mid Atlantic ridge, such rock (or lack of) should be very recent (well, recent geologically speaking).


I don't see how this could have happened, presumably the normal events that happen at a ridge somehow stopped working. How this could happen I have no idea. Or the rock could have sunk, if it was dense enough, but It would still need enough strength to seperate from the plate.

I can't think of how the rock could stop being formed on the ridge, but that must somehow be the case.

The water may boil at that depth, but it will have enormous pressure, which may stop it from boiling.

Thank you calcoastseeker for the links. It answered a couple of questions I had.
But I can't find the answer to this one-
Does anyone know if the site of where this hole is in the North Atlantic Ridge is anywhere near the Bermuda Triangle??
Just a thought...

No, the Mid Atlantic ridge is at least 1,250 miles from Bermuda, so nowhere near it I'm afraid. Although some things associated with the Bermuda Triangle may have occurred in this region. But I'm no expert on the Bermuda Triangle.

The ridges are sites where the crust is being pulled apart, and magma is being upwelled and cooling into rock. The whole process is driven by plate tectonics. Ridges are 'spreading centers' where new crust is created. At the opposite edges, the shorlines, the oceanic crust collides with continental crust, which is lighter. SO the oceanic crust has no choice but to under-ride the continental crust, iow, it plunges into the mantle. These are areas of crust destruction. When they talk about seeing slabs of crust going to the core, thats what they are talking about.

news.bbc.co.uk...
"Usually the plates are pulled apart and to fill the gap the mantle underneath has to rise up. As it comes up it starts to melt. That forms the magma," he said.

"That's the normal process. Here it has gone awry for some reason.

So he is hypothesizing that the oceanic crust seperates at the ridge, and for some reason, the mantle, instead of rising and melting, stayed solid. Or at least, it didn't completely melt.

Serpentine is an alteration product of Olivine. The mantle is thought to be composed of Olivine, when peices of the mantle get ripped up or exposed, its thought to become Serpentine.

Here is a page on the mineraology and mechanics of some of it:
www.mpch-mainz.mpg.de...


Here is an illustration:

The ridges are sites where the crust is being pulled apart, and magma is being upwelled and cooling into rock. The whole process is driven by plate tectonics. Ridges are 'spreading centers' where new crust is created. At the opposite edges, the shorlines, the oceanic crust collides with continental crust, which is lighter. SO the oceanic crust has no choice but to under-ride the continental crust, iow, it plunges into the mantle. These are areas of crust destruction. When they talk about seeing slabs of crust going to the core, thats what they are talking about.

news.bbc.co.uk...
"Usually the plates are pulled apart and to fill the gap the mantle underneath has to rise up. As it comes up it starts to melt. That forms the magma," he said.

"That's the normal process. Here it has gone awry for some reason.

So he is hypothesizing that the oceanic crust seperates at the ridge, and for some reason, the mantle, instead of rising and melting, stayed solid. Or at least, it didn't completely melt.

Serpentine is an alteration product of Olivine. The mantle is thought to be composed of Olivine, when peices of the mantle get ripped up or exposed, its thought to become Serpentine.

Here is a page on the mineraology and mechanics of some of it:
www.mpch-mainz.mpg.de...


Here is an illustration:

Here's another illustration:


It would be interesting, for example, to see if the region of exposed mantle sits higher or lower than the nearby areas of the ridge, so we can see if it was a result of extremely fast or extremely slow spreading.


The ridge would normally be composed of very little sediment, and then the crust would be made up of layers of billow basalts and sections that are entirely composed of basaltic dikes. So it will be interseting to see if the hypothetical exposed mantle section has any structure to it (i'd supposed it wouldn't, because then it would've been a melt and would've been oceanic crust).

Is it just me, or does anyone else find it oddly amusing that the rock is called "Serpentine"?

Originally posted by Chronic_Blaze
Im no geologist and am very confused.

What exactly is there if the crust is not?
Is it just a massive hole 6-7 kms deep full of water?

Can someone with some expertise shed some light on this please.

Sung to the "Barney" classic...

"There's a hole... in the bottom of the sea... there's a hole... in the bottom of the sea...

... and the hole... has water in it... in the bottom of the sea...

You get the picture, if not just imagine the cheesiest effects w/a funky mermaid singing to 3 kids and a purple dinosaur!

Myself, I would envision hot magma
Can anyone say S-U-P-E-R V-O-L-C-A-N-O-E w/a whole lot of sea pressure keeping it in check?

[edit on 7-3-2007 by Ikema]

Originally posted by Ikema
Myself, I would envision hot magma
Can anyone say S-U-P-E-R V-O-L-C-A-N-O-E w/a whole lot of sea pressure keeping it in check?

Well, I would personally think that the rock which has been in contact with the ocean will be solidified, and the rest will be underneath that. I would expect that it will be spread out considerably and would not therefore be eruptable magma. Although, when thinking of the sizes involved, the Deccan Traps come to mind.

The Decccan traps

Off topic, but, when did this happen?

Nygdan
Member

so here's me tossing in a completely fantastical idea...

what if this was atlantis, and it sunk into the sea as per the story? some supposed experts on this lost continent place it somewhere about there in the mid atlantic.

anyone think i'm completely nuts?

-adhd