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20 votes
4 answers
16k views

What is the deepest we have ever gone into the Earth?

I remember Journey to the Center of Earth and wonder: What is the deepest in the Earth surface or below sea level we have traveled either by foot, sub, drill or camera?
Muze's user avatar
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17 votes
2 answers
2k views

At what point does plate tectonics stop?

As the core and mantle of the earth cools, it will reach a point where new crust cannot be produced. How can this point be calculated? If we can, has anyone done such calculations? Thanks!
rnrneverdies's user avatar
15 votes
3 answers
14k views

What do continents "lay" on?

It's a simple question.. What do continents "lay" on? Do they float on water? or are they huge bodies that "emerge" from the sea floor/bed? are they connected to the bottom of the oceans? Hope the ...
Matan's user avatar
  • 253
14 votes
4 answers
12k views

Can we really travel through earth's core?

Inspired by the movie, "The Core". Can we really travel through earth's core? I will provide 2 sub questions: Is there any substance that can resist the heat of earth's core? Between the crust and ...
Poomrokc The 3years's user avatar
13 votes
1 answer
316 views

Is Mars' mantle homogeneous or heterogeneous and what might this say about mantle convection?

A supervisor of mine made an off-hand comment about the fact that Mars used to have plate tectonics, and there is evidence that Mars used to have plate tectonics, however now it does not. The theory ...
AlexLipp's user avatar
  • 1,715
12 votes
1 answer
626 views

Are mantle plumes distributed around the core randomly or in a known pattern?

Background: The theory of mantle plumes is useful (although controversial) in explaining the occurrence of intra-plate volcanoes. The website here suggests that "hotspots" exist in fixed locations ...
Kenshin's user avatar
  • 7,596
11 votes
2 answers
3k views

From how deep in the mantle has any rock ever been brought to the surface? Have scientists found anything they believe originated in the outer core?

I wonder if this is even possible to know.... Do geophysicists and geologists have even a 'theoretical' idea about how deep Earth's churning of its layers goes?
Kurt Hikes's user avatar
10 votes
3 answers
58k views

How is heat transferred from the core through the mantle to the crust?

So, there are three main methods of transferring heat: radiation, convection/mass transfer, and conduction. Presumably radiation is not a major method of heat transport between the core and the crust, ...
naught101's user avatar
  • 5,435
9 votes
2 answers
243 views

Can volcanos cause isostatic depression

Isostatic depression is normally associated with glaciation, but can other geologic processes result in similar behavior of the lithosphere? Especially, can the weight of a volcano cause the ...
Sonya's user avatar
  • 93
9 votes
2 answers
3k views

How viscous is the Earth's mantle?

I'm posting here to get some more expert information based on this question. If the Earth were to stop rotating, removing the centrifugal force causing the equatorial bulge, how long would it take ...
JDługosz's user avatar
  • 193
8 votes
2 answers
2k views

What is meant by phase-change in mantle?

Phase transition usually means changing from liquid to solid phase. But in geology literature we come across transitions from one mineral to other mineral. For example olivine-spinel transition at 410 ...
Ather Cheema's user avatar
8 votes
1 answer
144 views

Magma resultant from group 1 and group 2 elements?

I was recently speaking with a geology professor over lunch at a university who has a theory that I've never heard before. His postulation was quite compelling and I was hoping to do a little digging ...
ylluminate's user avatar
8 votes
0 answers
85 views

By how much did the Earth's diameter decrease due to cooling, if at all, since it was formed?

The answer to How long until Earth's core solidifies? question cites an estimation that the Earth (as a planet, not the surface of it) has cooled down by about 250K since it was formed. The question ...
DDRRSS's user avatar
  • 181
7 votes
3 answers
1k views

How can we have "floating" and convection currents in a non-liquid mantle?

I've always thought the earth's layers were as follows: Crust, a few dozen KM think in most places Mantle, completely composed of liquid rock and molten metals, a few thousand KM thick Outer Core, ...
Ovi's user avatar
  • 317
7 votes
1 answer
4k views

What's the difference between the upper & lower mantle?

Recently I checked a picture about the geologic layers of the Earth, and I saw that the mantle is divided into upper and lower mantle. What's the reason of this differentiation?
Zoltán Schmidt's user avatar
7 votes
1 answer
994 views

How straight is the Kola superdeep borehole?

The legendary Kola superdeep borehole is about 12 km deep. To achieve such depth, a major difficulty is to make sure the borehole is vertical straight. Intuitively, when the borehole is deep enough, ...
S. Kohn's user avatar
  • 205
7 votes
2 answers
587 views

What fraction of Earth's crustal material survives the supercontinent cycle?

I know that things are not as simple, but for the sake of argument I'll assume a supercontinent cycle of $\sim$400 Myr periodicity is active on Earth. If that is the case, then my naive ...
AtmosphericPrisonEscape's user avatar
7 votes
1 answer
154 views

Was Earth completely covered in Oceans prior to the onset of plate tectonics?

Following recent develoments in geophysics (Schmidt et al. (2014), and a popular summary), we now know there to be a significant reservoir of water in the mantle-transition of planet Earth, now often ...
AtmosphericPrisonEscape's user avatar
6 votes
4 answers
2k views

Are all natural diamonds made of organic carbon material?

I've read that diamonds are created at a depth of about 180 km. By volcanic activity it comes above. But did plants and trees of 300 million years ago sink so deep? Or is it possible that inorganic ...
Marijn 's user avatar
  • 2,533
6 votes
2 answers
3k views

If people aim to reach the mantle, why don't they just use volcano craters?

Once in a while aspiring people aim to drill through the Earth's crust to reach the mantle, but why do they want that when the mantle is actually on or very close to the surface in volcano craters? ...
Giovanni's user avatar
  • 305
6 votes
2 answers
861 views

Why doesn't the Earth's outer core dissolve into the mantle?

It is well accepted that the outer core is made out of liquid iron and nickel, and as everything else it should tend to reach chemical equilibrium with its surrounding. In particular, I would expect ...
Camilo Rada's user avatar
  • 17.7k
6 votes
2 answers
238 views

When diamonds "migrate" from deep underground to the surface, do they maintain pressure inside when there is no more pressure outside? If so, how?

From Science News' A mineral found in a diamond’s flaws contains the source of some of Earth’s heat: A tiny bit of rock trapped inside a diamond is now opening a brand-new window into what the planet’...
uhoh's user avatar
  • 7,122
6 votes
1 answer
204 views

Can the crust be compared to an arch?

Since tectonic plates are held together by lateral stress, friction, and gravity, and the Earth is a sphere, they work just like a full-circle arch or full-sphere dome. So can the crust be compared to ...
Teki Haken's user avatar
5 votes
2 answers
4k views

What's the official reason why it became so hot in the Kola borehole?

The Kola drill went 'only' a third the way to the mantle, so its deepest point was still closer to the surface than to the mantle. Why did the drillers experience 180 °C when so deep, where did that ...
Greenhorn's user avatar
5 votes
2 answers
222 views

Do we know what the rigid mantle looks like?

The rigid mantle, which is hard and lies above the asthenosphere, is separated from the "crust" that we can see and touch by the Mohorovičić discontinuity. Wikipedia provides an image of what may once ...
Robert Columbia's user avatar
5 votes
1 answer
167 views

Is there a seismic discontinuity between the lithosphere and asthenosphere?

I've been learning about seismic discontinuities, mainly the 5 defined ones - Conorod discontinuity, Mohorovicic discontinuity, Repetti discontinuity, Gutenberg discontinuity, and Lehmann ...
Sasikuttan's user avatar
5 votes
2 answers
691 views

How likely are caverns inside the mantle?

Almost everyone wrongly assumes that the Earth's mantle is liquid, but it isn't (only the outer core is). Is it possible then that there are hollow spaces within the mantle, similar to caves in the ...
Giovanni's user avatar
  • 305
4 votes
1 answer
2k views

What will happen to the Indian plate after it slides under the Eurasian Plate?

What will happen if the Indian Plate is done sliding under the Eurasian plate? I hypothesied some possible answers. Tell me the answer and if my hypothesis is not correct. Most likely to least. It ...
Tardy's user avatar
  • 574
4 votes
1 answer
217 views

Why is the concentration of highly siderophile elements so uniform in the mantle?

The plot above is about the concentration of siderophile elements in the terrestrial mantle. From the logarithmic plot, we can deduce that the concentration of highly siderophile elements is quite ...
adwait naravane's user avatar
4 votes
2 answers
163 views

Using current technology, is it possible to directly measure magma flow in the mantle?

Can a device or radioactive tracer be inserted into a volcanic lava lake, sunk to the mantle, and study the flow of magma within the mantle?
Gstestso's user avatar
  • 1,379
4 votes
1 answer
108 views

Why was quartz not a major product of the Lunar Magma Ocean?

Fractional crystallisation generally makes magma more silicic. Why was a substantial quartz layer not a product of the stratification of the Lunar mantle?
Andykins 's user avatar
4 votes
1 answer
1k views

What is the difference between a depleted mantle, and a fertile or enriched mantle?

In a paper about the interior of the Moon, it references depleted mantle sources and enriched mantle sources. Sometimes the latter is referred to as 'fertile'. What is difference between the first two?...
Andy's user avatar
  • 71
4 votes
1 answer
62 views

Do there exist reasonable numbers on the density/radius/mass of the various geological layers of the Earth?

I've been doing some math on the radius of the core (inner core in particular), and I keep getting what look like nonsense results. The composition is supposedly nearly all iron, close enough to it ...
John O's user avatar
  • 141
4 votes
1 answer
503 views

Source of sub-surface ringwoodite water

I was reading about the discovery of vast amounts of water locked up in ringwoodite (see here). The authors of the study seem to suggest that previous ideas, involving water deposits being delivered ...
christopherlovell's user avatar
4 votes
1 answer
953 views

What's up with the "jelly sandwich" analogy of the lithosphere, asthenosphere and mesosphere?

Here's what I know: The lithosphere is hard because it is cold and low-pressure. The asthenosphere is more deformable because of higher temperatures and pressures. The mesosphere is below the ...
jvriesem's user avatar
  • 225
4 votes
0 answers
43 views

What is the minimum temperature difference to drive mantle convection?

The condition for convection to cease is that the Rayleigh number $$\mathrm{Ra}=\frac{g\rho\alpha L^3\Delta T}{\kappa\nu}\lessapprox 10^3.$$ For the Earth's mantle I have seen estimates of $\mathrm{Ra}...
Anders Sandberg's user avatar
3 votes
1 answer
441 views

Do subducted continents rise up again through ridges?

Layman here, sorry if this is a stupid question. I have a geology friend who recently told me that plate tectonics is like how warm milk cools on top to form thin solid layers. The convection cells in ...
AlphaLife's user avatar
  • 133
3 votes
1 answer
109 views

If the universe (and our galaxy) has about twice as many oxygen atoms as carbon ones, why does Earth have 300 times as many oxygen atoms as carbon?

A (relatively) recent 'Sky & Telescope' magazine feature story mentioned how little carbon the Earth has, and how some scientists' models predict we should somehow have even less.... So I looked ...
Kurt Hikes's user avatar
3 votes
2 answers
132 views

Need help understanding what an "isostatic model minimizing crustal deviatoric stress" means

Despite the background information coming from another body besides the Earth, the terms I would like to understand are historically geophysical in nature. Background: I just read today's news "...
uhoh's user avatar
  • 7,122
3 votes
2 answers
234 views

Why do buoyantly rising mantle minerals melt, yet buoyantly rising atmospheric waters condense?

In the mantle, minerals contained in buoyant plumes of rock undergo phase changes from solid to liquid (decompression melting). In the atmosphere, waters contained in buoyant plumes of air undergo ...
pop tart's user avatar
3 votes
1 answer
128 views

How do they get "deep lunar mantle" samples?

Phys.org's Study suggests Earth and Moon not identical oxygen twins says They found that the oxygen isotopic composition varied depending on the type of rock tested. This may be due to the degree of ...
uhoh's user avatar
  • 7,122
3 votes
1 answer
419 views

Why is the Lithosphere-Asthenosphere Boundary an Isotherm?

My understanding of the LAB is that it represents the point in the earth where the mantle undergoes a temperature activated mechanical change. The temperature of the boundary depends on the melting ...
Benjamin Rogers-Newsome's user avatar
3 votes
0 answers
131 views

What is the structure of the hot spot under Hawaii?

The Hawaiian Islands are formed by volcanic activity over a hotspot in the Earth's mantle. What is the shape of this hotspot in the mantle? Is it like a pyramid or a pillar or an upside-down pyramid?
Marijn 's user avatar
  • 2,533
2 votes
2 answers
1k views

How is dense magma able to rise and punch through continental crust?

I am trying to understand how a dense basaltic lava is able to rise and punch through the continental crust, such as in mantle plumes or the Great East African Rift. My understanding of plate ...
G. Gip's user avatar
  • 772
2 votes
2 answers
3k views

Which one is the correct concept of Continental Crust and Oceanic Crust?

I knew so far that, the classification of crust as SiAl-SiMa, vs. classification of crust as Continental-Oceanic; are completely different, as told in my school geography and university paleobiology ...
user avatar
2 votes
1 answer
530 views

Does this support Hapgood's Earth Crust Displacement Theory?

I'm no Geologist by any standard but I'm quite intrigued by what goes on below our feet. I came across this article that states there's a new or (confirmed) partially melted layer in the athenosphere (...
Andyhasaquestion's user avatar
2 votes
2 answers
352 views

How is the difference in crust and mantle composition explained?

We know that the composition of the crust is SiAl and SiMa and the one of mantle is mostly ophiolites, but why? Which are the geological processes that make this difference exist?
Nikolina's user avatar
2 votes
1 answer
256 views

Why the "Mission to Earth’s core" proposal suggests using liquid iron instead of lead?

Nature communications article "Mission to Earth's core — a modest proposal", suggests placing a large volume of liquid iron in a crack and let it sink all the way to the Earth's core, carrying along a ...
Camilo Rada's user avatar
  • 17.7k
2 votes
0 answers
135 views

What makes special a volcanic pipe to be stable until the mantle?

Comming from this question: Can we really travel through earth's core? I wonder what makes special a volcanic pipe to be stable since the mantle through the surface, in comparison to our try or ...
user avatar
1 vote
1 answer
376 views

What is the earth's core temperature?

What is the earth's core temperature and is it really directly related to the earth's mantle?
MissLucy0909's user avatar