How come the ocean hasn't been absorbed into the ground?

[sheshank]

Whilst intuition can be a useful guide in dreaming up hypotheses, predictions and experiments, intuition is not a strong pillar of truth. Scientific knowledge comes by researchers applying the scientific method.

It is well established fact that water lowers the melting temperature of rock, and this has been verified over and over again in labs all around the world. I suspect that your conceptual model of what is happening is wrong. The water itself gets into the crystals that make up the rock, I suspect you are thinking of the water as being "free", but we are actually talking about the water as getting incorporated into the very rock itself. In this case the water is part of a solid constituent, not liquid or vapour. The effect of the water on this constituent is what we are talking about.

Let me tell you my point of logic (Warning ! it may be a false reasoning). A hard rock when is complete solid, can never allow water into it. But, gradually as the temperature increases (pressure is constant here), the rock starts to become soft giving chance for the pores to form. In our case, these pores are filled with water molecules which is the Absorption (Adsorption) phenomena. It obviously reduces the temperature conditions of the rock. But, when the same is subjected to conditions under pressure, the rock pores will compress leading the water to exhaust outside - just like a sponge squeased out of water. How much ever you may squease a sponge, it still remains wet. I expect the same to happen with the rock and Earthly conditions. A squeased sponge's properties obviously changes, but not considerably - compared to the case where the sponge is completely adsorbed with water. But, remembering that sponge particles, the particles of which the sponge is actually made, don't keep water molecules attached with them or react with them.

I am very sorry, My English is so limited and I can't explain better than this. If it doesn't reach you, then I am helpless. I'll try to improve my english.

 

[billiards]

A hard rock when is complete solid, can never allow water into it.

Um, I think you should really challenge your underlying assumptions. If this turns out not to be true, anything you infer from it is likely to be wrong no matter how solid your reasoning.

From your post, again I would reinforce that you are not "seeing" what's happening properly, your conceptual model of the situation is flawed. The water molecules themselves become incorporated into the crystal lattice of the rock. The water does not exist in pores -- the water itself becomes part of the rock! At high pressure rocks don't even have pores. Perhaps you need to review your whole conception of what a rock is?

 

[sheshank]

Um, I think you should really challenge your underlying assumptions. If this turns out not to be true, anything you infer from it is likely to be wrong no matter how solid your reasoning.

From your post, again I would reinforce that you are not "seeing" what's happening properly, your conceptual model of the situation is flawed. The water molecules themselves become incorporated into the crystal lattice of the rock. The water does not exist in pores -- the water itself becomes part of the rock! At high pressure rocks don't even have pores. Perhaps you need to review your whole conception of what a rock is?

I think my conscience is too much effected here, or is it that all of you are misconceived. Or is it my English fault. I don't know, my eyes and knowledge is getting masked.

 

[Borek]

See for example http://en.wikipedia.org/wiki/Mineral_hydration, http://en.wikipedia.org/wiki/Water_of_crystallization, http://en.wikipedia.org/wiki/Hydrate#Inorganic_chemistry

 

[sheshank]

See for example http://en.wikipedia.org/wiki/Mineral_hydration, http://en.wikipedia.org/wiki/Water_of_crystallization, http://en.wikipedia.org/wiki/Hydrate#Inorganic_chemistry

Thanks for the links...

I heard and read about Hydration. As that was not my branch, I didn't care much about it. But, it still makes me wonder, if that could be applied at extreme conditions. I have to accept the fact having looked at the links.
Water of crystallization is something which I have heard just the second time. Somebody in my childhood said, rocks contain water inside themselves. I didn't believe him. I think, I should believe him now.

 

[Flatland]

Mentor note:
This post was asked as a separate thread. Since it's a rehash of original post, and made by the original poster, this new thread is being merged into this existing one.How come the Earth's oceans didn't get absorbed or slowly leak into the ground over the past 4.5 billion years? Especially when the Earth has tectonic activities and the crust constantly split open and closes...etc.

 

[Borek]

Let's assume water seeps down. What is the temperature deep down? What form does water take there? What would happen next?

 

[russ_watters]

The ground isn't porous once you get a good distance down: there is nowhere for the water to go.

 

[D H]

How come the Earth's oceans didn't get absorbed or slowly leak into the ground over the past 4.5 billion years? Especially when the Earth has tectonic activities and the crust constantly split open and closes...etc.

Short answer: It does. It also comes out of the ground.

Oceanic crust is constantly being created and destroyed. New oceanic crust is created at the mid-oceanic ridges is pretty much void of water. Water seeps into that oceanic crust as it ages and is pulled toward subduction zones. A hundred or so million years later, that now saturated oceanic crust is subducted into the Earth. Most of the water comes right back out in the form of volcanic steam.

After 4.6 billion years, the amount of water in the oceans versus in the rock has reached an equilibrium (better: steady-state) value. About the same amount seeps in as comes out.

 

[OmCheeto]

We had a similar thread a while back. I think I discovered that 4 or 5 times as much water has been absorbed by the crust than there is in the oceans. If you were to squeeze it all out, the water level would rise to the point that would require all of humanity to live on just a few island chains.

I'll try and find the old post after work. I seem to recall posting pictures.

Ah ha!

https://www.physicsforums.com/showthread.php?p=3873049

 

[OmCheeto]

How come the Earth's oceans didn't get absorbed or slowly leak into the ground over the past 4.5 billion years? Especially when the Earth has tectonic activities and the crust constantly split open and closes...etc.

Hey! You started that thread! Or do we have two Flatlanders?

 

[dkotschessaa]

Hey! You started that thread! Or do we have two Flatlanders?

Nope, same person. He posted twice on the first thread and then disappeared... (into the ground?) while everybody else discussed it.

-Dave K

 

[OmCheeto]

Nope, same person. He posted twice on the first thread and then disappeared... (into the ground?) while everybody else discussed it.

-Dave K

Well. um. hmmm...

Everyone was very polite this morning.

I recognized that people had seen the question before, as the answers were very brief.

I thought that it might be a senility test for a moment, and then realized I was quite late for work, and then, whilst sitting at a traffic light, realized that I had not flunked the test!

 

[OmCheeto]

I must say though that I thoroughly enjoyed the thread, as it raised a wide diversity of questions in my head:

What is a rock?
Is "Rock Salt" really a rock? Is "Rock Candy" a rock? They spontaneously melt at NOT & NOP^* when water is added.
Is that how I should explain billiard's "to melt rock, just add water" to grandma?

I was discussing the thread yesterday with my Armenian friend at work, and he asked; "Where did the water come from in the first place?"
At which point I got all Sagany; "Billions and billions of years ago, comets full of water and stuff bombarded the earth. That's where it came from."

Then I told him about how forum members were quite used to a new person showing up every week at the forum and ask the question; "What is gravity?"
To which he responded; "That is so 6th grade."
"Not at PF", I retorted. "The people there are freakin' brilliant! They use big words, and use complicated math, and drop names of famous scientists: Einstein, Minkowski, etc"

That evolved from the fact that Flatland was a bit unique, in that he was not a new person, and had asked the same question, two years apart.

--------

Anyways, looking back over the thread, it appears that I was rude at least twice. I accused billiards of playing an April fools joke, and I referred to Flatland as a "Rabble Rouser".

* Nominal OmCheeto Temperature(72°F) and Pressure(14.7 psi)

 

[billiards]

Not this old thread again. Looking back at it some of my writing was horrible. It took me a while to figure out what the hell I was thinking.

Omcheeto I was not offended by your accusations that i was an april fools joker, just a little mystified. I guess I didn't ever think that melting rocks by adding water was anything special. So I didn't understand that you found it quite a mind-boggling concept to accept. I guess on reflection now I realize that it actually is quite a weird phenomenon, and that people don't have any intuitioin for these things built into them, rather we only know this stuff because some scientists observe it empirically, and when I say "we" I guess I'm really only talking about a small subset of the population that have read or heard about these things.

 

[OmCheeto]

Not this old thread again. Looking back at it some of my writing was horrible. It took me a while to figure out what the hell I was thinking.

Omcheeto I was not offended by your accusations that i was an april fools joker, just a little mystified.

You would have to know my history of "PF and April Fools jokes" to understand why I'm always a bit suspicious that time of year:

April 3, 2010
...
Long before the 1st, I even went so far as to try and get Greg's dad to be my friend on facebook in an attempt to find out where the party was. Apparently, the conspiracy went way beyond just PF'ers, and included Greg's entire family. Oh what a tangled web you all weaved.

All in all, it was the best April Fools joke I've ever been subjected to.
Thanks for taking me for the ride.

ps. and I got two new facebook friends out of the deal!
...

I guess I didn't ever think that melting rocks by adding water was anything special. So I didn't understand that you found it quite a mind-boggling concept to accept. I guess on reflection now I realize that it actually is quite a weird phenomenon, and that people don't have any intuitioin for these things built into them, rather we only know this stuff because some scientists observe it empirically, and when I say "we" I guess I'm really only talking about a small subset of the population that have read or heard about these things.

Yes, we surface folk just don't think about such things.

There are 3 main reasons I join threads:
1. I have something to teach
2. That is a really interesting question, and I might learn something
3. Pictures of kittens :tongue2:

This one fell into category 2.
I really appreciate you teaching me about rocks and water.

What was that old quote?

In the weeks after you taught me that, I must have started at least 30 conversations with;

Guess what I just found out!

Of course, no one believed me.