<p>If the question is actually &quot;why don't any geologists believe that Earth's surface and near-surface waters were brought up from <em>the Earth's interior</em>?&quot;, then the premise is false since many geologists do believe that is possible, e.g. see</p>
<ul>
<li>Earth Science SE post on <a href="https://earthscience.stackexchange.com/q/13366/27775">&quot;Water on Mars and Earth&quot;</a></li>
<li>Earth Science SE post on <a href="https://earthscience.stackexchange.com/q/14292/27775">&quot;Ocean water coming from Mantle vs coming from meteorites&quot;</a></li>
<li>Wikipedia's article on <a href="https://en.wikipedia.org/wiki/Origin_of_water_on_Earth" rel="noreferrer">&quot;Origin of water on Earth&quot;</a></li>
<li>Science article on <a href="https://www.science.org/content/article/earth-may-have-kept-its-own-water-rather-getting-it-asteroids" rel="noreferrer">&quot;Earth may have kept its own water rather than getting it from asteroids&quot;</a>.</li>
</ul>
<p>If you are specifically referring to plate tectonics, then as discussed in <a href="https://earthscience.stackexchange.com/a/22375/27775">&quot;Was Earth completely covered in Oceans prior to the onset of plate tectonics?&quot;</a>, the answer may depend on how &quot;plate tectonics&quot; is defined.  Earth scientists have <a href="https://phys.org/news/2014-12-hints-ancient-earth-watergeologically.html" rel="noreferrer">have done research related to the hypothesis</a> &quot;that Earth was formed with entire oceans of water in its interior, and has been continuously supplying water to the surface via plate tectonics ever since&quot;.</p>
<p>There certainly exists a <a href="https://en.wikipedia.org/wiki/Deep_water_cycle" rel="noreferrer">deep water cycle</a> exchanging water between the oceans and the mantle, so your question is just about what the starting conditions were: all the water in the mantle, all the water on the surface, or water in both.  We don't know the precise answer, but that doesn't make it a &quot;great mystery&quot;, just an area of research.</p>

CC BY-SA 4.0
2023-10-03T16:11:24.537Z
2023-10-03T16:11:24.537Z
David Bailey
<p>I read, periodically, that there is more water trapped in the mantle than there is in the oceans - possibly a lot more.</p>
<p>If so, why don't any geologists believe that Earth's surface and near-surface waters were brought up via plate tectonics?</p>
<p>Why do they always claim it is a great mystery concerning the origins of Earth's oceans?</p>

CC BY-SA 4.0
2023-09-28T22:36:02.280Z
Ok, so how did get it into the mantle then...? Who is they? [citation needed]
AtmosphericPrisonEscape
CC BY-SA 4.0
2023-09-29T00:21:28.980Z
"I read, periodically". Where do you read? Cite your sources.
Nilay Ghosh
CC BY-SA 4.0
2023-09-29T14:19:22.457Z
Eg, [Dehydration melting at the top of the lower mantle](https://www.science.org/doi/abs/10.1126/science.1253358) Schmandt et al. combined seismological observations beneath North America with geodynamical modeling and high-pressure and -temperature melting experiments. They conclude that the mantle transition zone—410 to 660 km below Earth's surface—acts as a large reservoir of water.
PM 2Ring
CC BY-SA 4.0
2023-10-17T07:11:01.947Z
If this was a question about how water arrived on the Earth, it would be an astronomy (astrophysics/cosmology) question. But it's not framed that way – instead, it's about a *geological* issue, which is off-topic here. I'm voting to close.
Chappo Hasn't Forgotten
<planet><earth><planetary-formation><water><geology>
Why don't scientists believe Earth's surface water came up from the mantle?
Kurt Hikes
# Why don't scientists believe Earth's surface water came up from the mantle?

(Asked by: username_0 on 2023-09-28)

I read, periodically, that there is more water trapped in the mantle than there is in the oceans - possibly a lot more.

If so, why don't any geologists believe that Earth's surface and near-surface waters were brought up via plate tectonics?

Why do they always claim it is a great mystery concerning the origins of Earth's oceans?

**Tags:** planet, earth, planetary-formation, water, geology
> **Comments:**
> **username_1**: Ok, so how did get it into the mantle then...? Who is they? [citation needed]  
> **username_2**: "I read, periodically". Where do you read? Cite your sources.  
> **username_3**: Eg, [Dehydration melting at the top of the lower mantle](https://www.science.org/doi/abs/10.1126/science.1253358) Schmandt et al. combined seismological observations beneath North America with geodynamical modeling and high-pressure and -temperature melting experiments. They conclude that the mantle transition zone—410 to 660 km below Earth's surface—acts as a large reservoir of water.  
> **username_4**: If this was a question about how water arrived on the Earth, it would be an astronomy (astrophysics/cosmology) question. But it's not framed that way – instead, it's about a *geological* issue, which is off-topic here. I'm voting to close.  

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## 1 answers

### Answer by username_5 on 2023-10-03. Score: 6

If the question is actually "why don't any geologists believe that Earth's surface and near-surface waters were brought up from *the Earth's interior*?", then the premise is false since many geologists do believe that is possible, e.g. see

* Earth Science SE post on ["Water on Mars and Earth"](https://earthscience.stackexchange.com/q/13366/27775)
* Earth Science SE post on ["Ocean water coming from Mantle vs coming from meteorites"](https://earthscience.stackexchange.com/q/14292/27775)
* Wikipedia's article on ["Origin of water on Earth"](https://en.wikipedia.org/wiki/Origin_of_water_on_Earth)
* Science article on ["Earth may have kept its own water rather than getting it from asteroids"](https://www.science.org/content/article/earth-may-have-kept-its-own-water-rather-getting-it-asteroids).

If you are specifically referring to plate tectonics, then as discussed in ["Was Earth completely covered in Oceans prior to the onset of plate tectonics?"](https://earthscience.stackexchange.com/a/22375/27775), the answer may depend on how "plate tectonics" is defined. Earth scientists have [have done research related to the hypothesis](https://phys.org/news/2014-12-hints-ancient-earth-watergeologically.html) "that Earth was formed with entire oceans of water in its interior, and has been continuously supplying water to the surface via plate tectonics ever since".

There certainly exists a [deep water cycle](https://en.wikipedia.org/wiki/Deep_water_cycle) exchanging water between the oceans and the mantle, so your question is just about what the starting conditions were: all the water in the mantle, all the water on the surface, or water in both. We don't know the precise answer, but that doesn't make it a "great mystery", just an area of research.


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