Volcanics on a FE?

(Partly because LyingTruth is being a jackass about the topic...)

How would the various types of volcanoes and volcanic settings work on a FE?

We have several different types in RET, I'm not sure how they would work on a FE, what with no discernible core/mantle, and outright rejection of plate tectonics in certain circles.  As I recall, the FAQ/Wiki doesn't answer these terribly well, either.

Mid Ocean Ridge volcanism.
This is caused by depressurisation of the upper mantle as the oceanic crust is pulled apart.  The lower pressure initiates a partial melt of the upper mantle, and forms a roughly Basaltic melt.  This can be seen all over the place beneath the sea, and on land as a Mid Ocean Ridge cuts through Iceland.

Island Arc volcanism.
Found around Subduction zones, these form when a plate is subducted.  As the plate is subducted, it gives off volatiles (mostly Water, and bits and pieces from the sediment that had accumulated on top of the plate). These volatiles lower the melting point of the overlying mantle wedge, and produces a Basaltic melt, that rises through the overriding plate and becomes more acidic through fractional crystallisation and assimilation of continental crust.  When this reaches the surface, it tends to be an Andesitic or Rhyolitic lava.  Or, it can find itself unable to rise, if it becomes too acidic, and you'll get a granitic pluton.

Hot-Spot Volcanism.
As found in Hawaii, and (if you look on topographic/bathymetric maps, the Emperor Seamount Chain) a rising plume of heat from the mantle, bringing with it deep mantle material, intersects with the crust and a volcano erupts.  A basaltic melt is produced, with markedly different geochemistry to the basalt of Mid Ocean Ridge basalt.

Thanks guys


(tl;dr - different types of Volcano and volcanic setting aren't described in the FAQ or Wiki, and I can't see how they'd work on a FE.)

Same way they work on an RE.

Do we need to explain how rain occurs on an FE too? 

I'm not sure how they would work on a FE, what with no discernible core/mantle, and outright rejection of plate tectonics in certain circles.

How can volcanoes work the same way in FE if it is missing these critical components?

Think it through Tom.  If you want to go right back to basics, we're looking at a large scale convection circuit.  Does that exist in FE, and if so, how does it work?  

(Partly because LyingTruth is being a jackass about the topic...)

How would the various types of volcanoes and volcanic settings work on a FE?

We have several different types in RET, I'm not sure how they would work on a FE, what with no discernible core/mantle, and outright rejection of plate tectonics in certain circles.  As I recall, the FAQ/Wiki doesn't answer these terribly well, either.

Mid Ocean Ridge volcanism.
This is caused by depressurisation of the upper mantle as the oceanic crust is pulled apart.  The lower pressure initiates a partial melt of the upper mantle, and forms a roughly Basaltic melt.  This can be seen all over the place beneath the sea, and on land as a Mid Ocean Ridge cuts through Iceland.

Island Arc volcanism.
Found around Subduction zones, these form when a plate is subducted.  As the plate is subducted, it gives off volatiles (mostly Water, and bits and pieces from the sediment that had accumulated on top of the plate). These volatiles lower the melting point of the overlying mantle wedge, and produces a Basaltic melt, that rises through the overriding plate and becomes more acidic through fractional crystallisation and assimilation of continental crust.  When this reaches the surface, it tends to be an Andesitic or Rhyolitic lava.  Or, it can find itself unable to rise, if it becomes too acidic, and you'll get a granitic pluton.

Hot-Spot Volcanism.
As found in Hawaii, and (if you look on topographic/bathymetric maps, the Emperor Seamount Chain) a rising plume of heat from the mantle, bringing with it deep mantle material, intersects with the crust and a volcano erupts.  A basaltic melt is produced, with markedly different geochemistry to the basalt of Mid Ocean Ridge basalt.

Thanks guys


(tl;dr - different types of Volcano and volcanic setting aren't described in the FAQ or Wiki, and I can't see how they'd work on a FE.)

Thanks a lot for the detailed article. I learned something new!

Didn't you say that plate tectonics don't exist?

There is a description of volcanoes in the Wiki:

A volcano is an opening, or rupture, in the Earth's surface, which allows hot, molten rock, ash and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time.

Volcanoes are generally found where tectonic plates are pulled apart or come together. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by "divergent tectonic plates" pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by "convergent tectonic plates" coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intraplate volcanism"), such as in the African Rift Valley, the Wells Gray-Clearwater Volcanic Field and the Rio Grande Rift in North America and the European Rhine Graben with its Eifel volcanoes.

Volcanoes can be caused by "mantle plumes". These so-called "hotspots" , for example at Hawaii, can occur far from plate boundaries.

Also, from the FAQ:

Q: "How do volcanic eruptions happen?"

A: The Earth is thick enough to have a core of molten lava. Once there is too much of it in too confined a space, it finds its way out, just like the water will come out of a full bottle if you squeeze it too hard.

There is a description of volcanoes in the Wiki:

Quote

A volcano is an opening, or rupture, in the Earth's surface, which allows hot, molten rock, ash and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time.

Volcanoes are generally found where tectonic plates are pulled apart or come together. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by "divergent tectonic plates" pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by "convergent tectonic plates" coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust (called "non-hotspot intraplate volcanism"), such as in the African Rift Valley, the Wells Gray-Clearwater Volcanic Field and the Rio Grande Rift in North America and the European Rhine Graben with its Eifel volcanoes.

Volcanoes can be caused by "mantle plumes". These so-called "hotspots" , for example at Hawaii, can occur far from plate boundaries.

Also, from the FAQ:

Quote

Q: "How do volcanic eruptions happen?"

A: The Earth is thick enough to have a core of molten lava. Once there is too much of it in too confined a space, it finds its way out, just like the water will come out of a full bottle if you squeeze it too hard.

Get your terminology right, Tom.  Lava is what is found on the surface of the Earth, what has been extruded.  Magma is the stuff beneath the ground.

So, what generated this magma?  What causes it to concentrate in this confined space?  How does it move from the core to volcanoes without cooling/solidifying first?

And, back to previous questions (directed at those who would believe Plate Tectonics do not exist) - How can this happen on a world with no plate tectonics?

I may be wrong, but some FE'ers do not disregard plate tectonics.

I may be wrong, but some FE'ers do not disregard plate tectonics.

Correct;