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

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The discussion explores why Earth's water has not been absorbed into the ground over billions of years, highlighting the role of geological processes. Permeability of various rock layers limits how deep water can penetrate, while the water table defines the saturation point of underground materials. Water does seep into the oceanic crust and is recycled through volcanic activity, where it returns to the surface as steam. The balance between water loss through seepage and replenishment from volcanic eruptions maintains the Earth's water levels. Ultimately, geological dynamics, including plate tectonics, play a crucial role in the water cycle and distribution.
  • #31
sheshank said:
I'll speak in very short sentences. The Earth's temperature rises every 300 mts deep by some extent (perhaps one degree or so). This happens when there is something to cover it up. For example, let's consider the case of digging up earth. If you dig up the Earth under one of the highest himalaya mountains to the sea level and compare it with the sea, you'll find the change in temperature. So, when it rains all water find slopes and reach oceans. Water accumulate together. They can't penetrate more deeper because, if they penetrate they'll face heavy temperature and have to come up again in the form of vapors through the tiny perforations of the crust. So, all the water stay where they are.

Sometimes water also goes deeper, like few said in this forum and it happens to support some chemical reactions like Formation of Natural gas and Fossil fuels etc. But, not all water can be sucked inside the Earth. I guess I cleared the initial doubt asked

Guess I am right with my explanation. Correct me if I am wrong.

That's the obvious first reaction, of course. But mixtures have different melting and boiling points from their individual constituents so it is not unthinkable that water could exist (as water) despite the high temperatures at great depth.
What you can read on the links on this thread suggest that it isn't as simple as one might think.
 
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  • #32
sophiecentaur said:
That's the obvious first reaction, of course. But mixtures have different melting and boiling points from their individual constituents so it is not unthinkable that water could exist (as water) despite the high temperatures at great depth.
What you can read on the links on this thread suggest that it isn't as simple as one might think.

Chemically reacted mixtures have entirely different boiling and melting points. That's sure. Other kinds of colloids formed due to water's mixture with something else can never have temperatures greater than a some or little above its boiling point. Like, salt water vaporizes slower than pure water. So, colloids or mixtures can't enhance or influence the temperature to a very great extent. Yes, they enhance and influence, but very little. If, its solutions that form a mixture, then they both must come to Earth's surface due to immense pressure. It just can't be! My common sense say this. I don't know what science speaks of this and to add, I am not a geologist. Its just an obvious thing in physics.
 
  • #33
sheshank said:
Chemically reacted mixtures have entirely different boiling and melting points. That's sure. Other kinds of colloids formed due to water's mixture with something else can never have temperatures greater than a some or little above its boiling point. Like, salt water vaporizes slower than pure water. So, colloids or mixtures can't enhance or influence the temperature to a very great extent. Yes, they enhance and influence, but very little. If, its solutions that form a mixture, then they both must come to Earth's surface due to immense pressure. It just can't be! My common sense say this. I don't know what science speaks of this and to add, I am not a geologist. Its just an obvious thing in physics.

You don't need a chemical reaction between glycerol and water or between mercury and copper to change the melting point considerably.
You say that you are speaking as a Physicist (and so am I) but I, certainly, have little knowledge of the behaviour of substances at extreme pressure. Do you?

If you look at the phase diagram of water, it remains solid at very high temperatures when the pressure is high enough. I think we need to look in much more detail if we want to be able to hold a valid opinion about this. Personally, I'm open to any good information that turns up on this thread.
 
  • #34
sophiecentaur said:
You don't need a chemical reaction between glycerol and water or between mercury and copper to change the melting point considerably.
You say that you are speaking as a Physicist (and so am I) but I, certainly, have little knowledge of the behaviour of substances at extreme pressure. Do you?

If you look at the phase diagram of water, it remains solid at very high temperatures when the pressure is high enough. I think we need to look in much more detail if we want to be able to hold a valid opinion about this. Personally, I'm open to any good information that turns up on this thread.

By the word "Science" I mean to say not just physical or chemical or geological but any. That's why I mentioned that I am not a geologist and my common sense speaks what I mentioned.

I think there doesn't need any knowledge other than those few Gaseous laws of Robert Boyle and Charles. So, I proposed my 'common sense' based on this.

Water can never stay in solid form inside the deep layers of earth. Either it should be in the form of colloids (liquid form) or gaseous form. I don't have a confirmation whether the water is in gaseous form under the Earth. (If so, then there should be sesmic vibrations experienced all around the Earth, not just at the places where techtonic plates collide).

How much ever water tries to form a colloid its polarization (because its a non-polar solvent) can't cross more than 180 degrees. Anything more than 120 degrees of polarization is quite impossible without electric supply. Water needs to form heavy polarization with is fellow colloid in order to sustain such heavy temperatures. In that case water molecule simply breaks down rather than staying there completely polarized.

There are two cases where water may form colloids. 1) solid in Liquid 2) liquid in liquid.
If solid in liquid is the case, then water definitely stays away from the solid it is mixed with, since their densities vary by heavy amount which makes them impossible to mix, unless they react chemically. Its a kind of Adsorption phenomena. Even if they mix, water can't account for greater than 2-3% of the colloid just soaking it wet. Given the area taken into consideration (as radius sinks and so is surface area as we go deep), we find very little water in the deeper layers of the earth.
If liquid in liquid is the case. Liquid can mix with liquid only in case as mentioned above (polarization). If there is some material in the form of liquid at that particular (heavy) temperature and pressure, then it must have heavier energy due to brownian motion. We know, when such high energy molecules collide with water molecules of lower energy, they, obviously, are ejected out. This is the practical case.

I state again, I am not a geologist, nor a chemist, nor a physicist. I stated something out of common sense and my high school chemical sciences. There may be other factors taken into consideration which I am not aware of. If anyone cares to mention them, I'll be glad to know about.
 
  • #35
sheshank said:
I stated something out of common sense and my high school chemical sciences. There may be other factors taken into consideration which I am not aware of. If anyone cares to mention them, I'll be glad to know about.

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.
 
  • #36
billiards said:
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.
 
  • #37
sheshank said:
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?
 
  • #38
billiards said:
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.
 
  • #40
Borek said:

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.
 
  • #41
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.[/color]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.
 
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  • #42
Let's assume water seeps down. What is the temperature deep down? What form does water take there? What would happen next?
 
  • #43
The ground isn't porous once you get a good distance down: there is nowhere for the water to go.
 
  • #44
Flatland said:
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.
 
  • #45
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
 
  • #46
Flatland said:
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?
 
  • #47
OmCheeto said:
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
 
  • #48
dkotschessaa said:
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! :smile:
 
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  • #49
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". :redface:

* Nominal OmCheeto Temperature(72°F) and Pressure(14.7 psi)
 
  • #50
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.
 
  • #51
billiards said:
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:

OmCheeto said:
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 :-p

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

What was that old quote?

eleanorroosevelt385439.jpg

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.
 

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