Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum vast water reservoir hidden beneath the earth

If I recall in a previous thread , one of the main objections
to the account in the Bible of the Great Flood ( Noahs Ark ) was that there could not have been enough water to cover all of the mountains on the earth.

Looks like that objection no longer holds water!

Paul, I thought about you when that news broke.

How aware are you of the actual situation, and the way in which this “water” would be incorporated into the mantle?

As so often happens, the media have (perhaps with some justification in the light of Graham Pearson’s over exuberance) dramatised the situation.

One minute “drop” of water in one crystal of ringwoodite from one location in the transition zone is hardly proof of subterranean “oceans”.

If that amount of water really is there it will be built into the crystal lattices of the minerals. Try wringing water out of an opal!

Much of the so-called water in rocks is incorporated as OH molecules, which are not even wet, but are commonly referred to as "water" content.

A lot more samples, from a lot more locations, would be needed to provide anything like scientific proof of anything remotely “oceanic”. For the moment, it’s little more than media hype.



Mail = Encyclopaedia fox populi.



1.5% of what; a miniscule crystal of ringwoodite?

I suppose its a little too early to be defending the find.
the article was published today.

I can say that an increase of temperatures would release the
O and H from the crystals as the crystals become liquid.

as the O and H gasses rise to the surface fractures in the rock can produce electric discharges due to pressure buildup and sudden release which could combine the H and O into H20 molecules forming water and the gasses that reach the surface could be combined into water as lightning could combine the H and O into water as H20.

also it could just as easily rain for 40 days and 40 nights...

And that would have been quite a deluge. In 40 days and 40 nights it rained 29,000 feet over all the surface of the Earth. To simplify the math let's say 28,000. That comes to 70 feet per day, or approximately 3 feet per hour. I'm surprised the ark didn't swamp under that kind of a deluge.

Bill Gill

It is relatively easy to extract water from a mineral such as selenite (CaSO4.2*H2O) by heating; but not so easy to extract it from the hydrated form of talc (Mg3Si4O10(OH)2.) and less easy from a ring silicate, which is the sort of thing you would be more likely to have to deal with in the mantle.

Then you would have to explain where sufficient heat came from to dewater the transition zone, and drive that water to the surface.

If you did that you would have to explain how the transition zone could shrink by about 1% without causing major tectonic disruption to the overlying mantle and crust, which, far from having shrunk, would have to swell to accommodate the passage of the water.

Possibly this could produce relatively small quantities of water, but to produce the quantities necessary for the “flood” would result in the sort of tectonic disturbances that would have left a very distinctive mark in the geological record, everywhere in the world.

I think you might have to find evidence of worldwide, contemporaneous volcanic activity of the sort that formed the Deccan Plateau before you could make a cogent argument for dewatering the transition zone.

If you could do that, and explain the source of the heat, you could probably make a good argument for the water evaporating and resulting in a vast amount of rain. You might have trouble fitting it all into the Biblical time scale, though.

Stick with it Paul, I welcome any excuse to rethink my rusty geology.

yes , but you shouldnt confuse this deluge with the comparatively low amounts of rainfall that the earth receives due to solar radiation.

thats kind of like comparing a firecracker to a hydrogen bomb.



there are recent records that show several feet in a 24 hour period from solar radiation alone and that radiation is
apx 93 million miles away.




it was probably really rough at first but as more and more land was covered the water would calm down because it could flow over the areas where land once blocked it from flowing.

like the smooth rolling waves in the middle of todays oceans.




try this

from around 130,000 years ago until
around 13,000 years ago a very large amount of the earths
water became locked up in ice.

the ice formed around the north and south poles.
and extended towards the equator for thousands of miles
and was several miles thick.

thats a lot of weight moving to the center of rotation
and this movement of mass to the center of rotation caused
the earths crust to spin faster.

so the earths crust was spinning much faster than it is today.

and the friction between the magma and the earths core caused an enormous amount of heat that was transfered into the magma
this caused the transition zone to heat up , and along with the heating up , the magma that melted the transition zone and filled the transition zone expanded the way that magma / all matter does due to temperature increases.

That may seem like a lot of ice, and a lot of weight, but in relation to the volume of the Earth it's not a lot.

Consider that the oceans comprise about 0.1% of the volume of the Earth, and that there is no evidence that at any point the oceans were completely frozen. That is, unless you include the Pre-Cambrian "Snowball Earth" theory; and I suspect the Pre-Cambrian may be a bit far in the past for your liking.

Another consideration here is that the oceans form part of the crust, as did the ice, so the phase change from water to ice is not going to add weight to the crust. The transfer of water from the oceans to ice on the land caused isostatic readjustment, but that would not involve the sort of movement that would increase friction in the transition zone.

the problem with your reply is that the earths crust only makes
up apx 1% of the earths volume.

the earths crust is like the rubber part of a inflated rubber balloon.

the crust is not attached to the magma underneath it and the earths crust floats on top of the magma.

the crust , the mantle , and the core all spin independently of each other and at different speeds from each other.




http://pubs.usgs.gov/gip/interior/

I could clearly understand your comment if the earth were a solid ball , because that amount of mass moving towards the center of rotation would not matter much at all.

but the earth is far from being a solid ball.

Not the best analogy, Paul.



This suggests that there is a layer of magma under the crust. That is not quite the situation. Magma occurs only locally, where temperature is higher than in surrounding areas.

You are absolutely right in saying that the comparing the Earth to a solid ball is not right, in that it is a dynamic body, but in the normal usage of the word, it's quite solid, the internal movement is very slow. It is a common mistake to think that the motion of tectonic plates involves the sliding of crustal plates over the mantle at the Mohorovicic discontinuity. In fact, the upper mantle moves with the plates.



There is a small difference between the rate of rotation of the core and mantle, but as far as I am aware, the only difference between the movement of crust and mantle is caused by plate movements, which is certainly not unidirectional spin, and the plane of differential motion is not at the base of the crust.

to me that sounds like you were saying that the rest of the earth would prevent the crust from spinning faster because of
its mass , like it were a solid.





I didnt say that weight would be added to the crust , did I?



I didnt say anything about the sliding of the plates , I said that the earths crust would spin faster.



I didnt say that either , I said this



when I wrote this.



I meant the earth floats on the mantle , not the magma.

still any increase of spin of the crust will translate into heat inside the earth , the spin that we have today causes
the temperature of the bottom of the earths crust to reach
temperatures of 1600 F +.

if the earths core did not spin at a different speed than
the earths crust then the earth would freeze solid.

there would be no friction to heat the earth.




in fact the extra spin of the crust that would be the result
of ice gathering at the poles is possibly the reason that
the earth has recovered ( began to warm up ) at the height
of the many ice ages it has had in the past.

Paul, given that you didn't say the various thing you claim you didn't say, I shall have to devote a little effort to finding out what you actually said and seeing if it makes any sense to me.

Perhaps we are making the mistake of trying to cover too many different points in a single post. How about we take one point at a time?

Let's start with this.



If you were not saying that this involved an increase in mass/weight of the crust, why would there be any difference in the tendency for movement towards the centre of rotation before and after the formation of ice?

If you were not saying that this involved an increase in mass/weight of the crust,

its not an increase of mass/weight of the crust.

why would there be any difference in the tendency for movement towards the centre of rotation before and after the formation of ice?

that is explained a little better further down.




thats a lot of weight moving to the center of rotation...

the earths crust holds the oceans weight , the sea level of
the earths oceans undergo a significant drop during an ice age.

apx 100 meters lower than today.

and this movement of mass to the center of rotation

the worldwide drop in sea levels of apx 100 meters gathered
at and around the earths poles.

caused the earths crust to spin faster.

if you understand physics then you understand that by moving
mass toward the center of rotation gives energy to the rotation (increases the rotational speed).

there does not need to be any additional force applied for the
increased rotational speed and there does not need to be any additional mass added for the increased rotational speed.

the reason that the rotational speed increases is because the
energy needed for angular acceleration of mass further from the center of rotation is greater than the energy needed for angular acceleration of mass when it is closer to the center of rotation.

since the earths crust already had angular momentum before the
ice age relocated a vast amount of the earths ocean water to the poles , any movement of mass to the poles would add angular
acceleration to the earths crust increasing the angular momentum of the earths crust. (increasing its rotational speed)

picture one of the round swimming pools that you can buy
20 feet in diameter and has a height of 5 feet and its filled with water.

only it is made of stainless steel.

it holds 1,570 cu ft of water.

in the center of the pool there is a 2 foot diameter stainless steel drain pipe that is capped at the bottom and extends to a verticle depth of 500 ft.

the pipe is baffled so that water can not spin inside it.

it can hold 1570 cu ft of water.

the drain pipe is not filled with water.

at the top of the drain pipe there is a water valve that
when opened will allow water to flow through it at a
flow rate of 1 gallon per minute.

the water valve is remotely controlled.

the entire contraption is attached to an axle and the axle is mounted on frictionless bearings.

you apply a force that rotates the pool containing the drain pipe and the valve and the 1,570 cu ft of water to a rotational speed of 1 rev per 24 hours.

the valve is remotely turned on and water begins to flow from the pool into the 500 ft of drain pipe.

after 1,570 minutes have passed the pool will be empty and the drain pipe will be full , and the pool the drain pipe and valve and water will be rotating faster than you first rotated it.

there has been no weight added , there has been no energy added (except that used to open the valve), there has been no additional momentum added.

if you calculate the initial momentum and the final momentum
it will be the same. (or the difference will be negligible)

the overall contraption is rotating faster.

1,570 gallons of water has moved closer to the center of rotation.

I understand the physics of moving mass toward the centre of rotation increases the speed of rotation, but I thought it wise to make sure we were talking about the same thing before moving on.



Two points are worthy of note here:

1. The build up of the vast thickness of ice took thousands of years. Over those same thousands of years local vertical movements of crust and upper mantle would take place as isostatic equilibrium was slowly restored. The maximum ice thickness would, roughly, be contemporaneous with the maximum crustal depression, thus minimising the effect you describe.

2. As far as I am aware the Mohorovičić discontinuity does not constitute a surface of slippage on a global scale. Perhaps I should look these things up rather than relying on memory, but where do you get the idea that the crust and mantle spin at different rates?

As I said above; I am aware that there is a difference between the rotation rates of core and mantle. The difference would be between inner core and mantle, and it is the core that rotates faster. What evidence do you have that the crust might rotate faster than the mantle?

You may point out that you didn’t say that, but if increasing rotational speed of the crust increases friction, then it cannot be because the mantle was formerly rotating faster.

I like your contraption, but it bears little, if any, relation to the situation in question.

Paul, you might want to check the math on how much the Earth would speed up with the weight of the water moved to the poles. On a very simplistic calculation I find that the mass of 100 feet of water from the surface of the ocean would be about 2.35 * 10^16 lbs. The mass of the Earth is about 1.32 * 10^26 lbs. That means that 1/10,000,000,000 of the Earth's mass would be moved to the polar regions. I'm afraid that amount of mass would have almost no effect on the rotational speed of the Earth.

Your explanation that the crust is not rotating at the same speed as the core doesn't really help all that much. They are still coupled together by fluid dynamics, and the whole Earth would have to speed up. Keep in mind that fluid coupling works quite well in the transmissions of most cars on the road today.

In your example with the fancy funnel the vast majority of the mass of the system would move to the axis of rotation. That would have significant effect on the rotational speed of the system. So it is not a very good analogy to the problem of the water moving to the poles.

And one very minor correction. You kept talking about the water moving close to the center of rotation of the Earth. You probably meant the axis of rotation, which is a more correct statement. The center of rotation is at the center of the Earth, approximately equidistant from all points on the Earth's surface.

Bill Gill

Even that small effect is diminished by isostatic readjustment.

I've just looked back at my earlier post. I guess I shouldn't have put the accents on the "c"s of Mohorovicic! I assume that's the problem.

Bill S.


I just figured it did when I thought about what could cause the
earth to recover from the many ice ages in its past.



it just so happens that the core does spin faster than the earth , not only does it spin faster it spins in
opposite directions , the inner core super rotates in a
eastward direction , the outer core rotates in a westward
direction while the earths crust rotates in a eastward direction.

that doesnt really sound like theres much solidarity
going on in there.





the mantle , in my opinion moves at apx the same speed
and direction as the crust where the two meet , then as depth increases the speed of the mantle gradually decreases until
at some depth the speed of the mantle goes to zero and then reverses direction as it is dragged into a new direction by the westward spinning outer core.

the mantle obviously isnt a solid , so it would follow the way
that a fluid would react in this same situation.

of course there is much more to it than the above , but that should do as a summary.

I believe that the core moves around inside the earth also.
and spins at more than one direction.

Bill



its a good thing that the crust isnt attached to the other 99%
of earths mass.

and it was 100 meters not 100 ft.

and you would need to remember that the crust only makes up
apx 1% of the earths mass and volume I think.

and the seas make up only .1% of the earths volume.





yes , if I thought about it that way I would agree with you.
but since the earth is not a solid ball , I'm afraid I cant.



yes , and fluid dynamics includes the viscosity of fluids and the vast amount of heat down there means that the atoms do not interact that well , the degree of viscosity / friction is vastly diminished from what it would be if it were solid rock , still given the pressures down there the viscosity would be enormous.

viscosity is like the friction of a fluid.



you would think that if that were true then there would be
no differences in the speeds of the many layers of the earth.

but I suppose that isnt true.



the example was just that , an example.

and it clearly shows what would happen to the rotation of the entire system if mass moves towards the center.



I was talking about the earths rotation , I just figured that Bill S already knew that.

Paul, your latest post deserves more comment than I have time for at present, but one thing I must ask is, where did you get the information that the core and mantle rotate in opposite directions? That is not my understanding.

A reasonable thought, but certainly not supported by evidence from the study of seismic waves.