Too deep, too hot to reach; camera would melt. Drilling equipment would melt. Pressure would crush all of it. It might be there, but we can't reach it.

{How come a Camera was not sent in?}

"at depths between 250 miles and 410 miles."

The deepest humans have ever drilled is 7.6 miles.

"Though not in the familiar liquid form..."

Nothing to see, folks. No underground floods, lakes or contiguous water features. Just slightly more of certain hydrated minerals than expected. Can't even get the water out without roasting a sample-- If we could drill that deep. But, that modest H2O content lowers the melting point, like Cryolite flux in Aluminium production...

I came here expecting to see a Creationist Noah's Ark flame war starting (whatever happened to kevintrs, anyway?) though I suppose there would be far more than five answers in that case, found only a camera faux pas, and ended up confused on the following point. I freely admit to being uneducated in geology and Earth science.
"Melting of rock at this depth is remarkable because most melting in the mantle occurs much shallower, in the upper 50 miles,"
My admittedly simplistic understanding was that only Earth's crust is solid, with the remainder being molten or at least plastic, depending on depth. So why would melting at 'only' 400 miles be considered remarkable, when melting at 50 miles is not? Is it because most matter at this depth is only plastic and not molten, and is happening in these spots because of the presence of H2O, or some other reason?

RE: The mineral Ringwoodite: Ringwoodite is a polymorph of olivine, with a spinel structure. Ringwoodite can have deep blue, red, violet, or colourless (pure Mg2(SiO4)) appearance.

This info from Wikipedia. Posted because this article seems to have neglected the chemical formula for the mineral Ringwoodite. A shocking oversight! Well, maybe not shocking.

What is the transport mechanism for surface water to ringwoodite and back to the surface?
Does this regulate the amount of water on the surface?

I came here expecting to see a Creationist Noah's Ark flame war starting
Well verily because The Lord said specifically in his book:

"11 In the six hundredth year of Noah's life, on the seventeenth day of the second month—on that day all the springs of the great deep burst forth" gen7

-And from a creationist website entitled
'Physics and the Bible:
The Terrible Flood of Noah
by Lambert Dolphin'

-we find

"During the formation of the earth on the second and third days of creation, large quantities of water were evidently placed between the earth's crust and mantle in what might be called giant subterranean reservoirs. This water was probably under high pressure to begin with (causing artesian springs and geysers to abound"

-And so we can expect religionists to be rejoicing at the news that god has again described what science has subsequently verified.

It doesn't matter to them that this water is chemically bound the way that H2 and O are similarly bound. God doesnt quibble.

There's 'primordial' water from the Earth's formation plus 'Big Splat', and there's the subducted stuff. IIRC, much of North America is underlain by descending fragments of the Farallon oceanic plate...

I came here expecting to see a Creationist Noah's Ark flame war starting
Well verily because The Lord said specifically in his book:

"11 In the six hundredth year of Noah's life, on the seventeenth day of the second month—on that day all the springs of the great deep burst forth" gen7

"During the formation of the earth on the second and third days of creation, large quantities of water were evidently placed between the earth's crust and mantle in what might be called giant subterranean reservoirs. This water was probably under high pressure to begin with (causing artesian springs and geysers to abound"

So... you are saying earth's vast oceans and bodies of water came from comets?
It seems to me, and the researchers at Northwestern and Univ. New Mexico are saying otherwise.

It seems to me, and the researchers at Northwestern and Univ. New Mexico are saying otherwise.
The article says nothing about where it came from, only how it got into the mantle.

"The discovery suggests water from the Earth's surface can be driven to such great depths by plate tectonics, eventually causing partial melting of the rocks found deep in the mantle."

-Did you read it?

@ryggysoggy

What is the transport mechanism for surface water to ringwoodite and back to the surface?


AGWites and socialists.

Does this regulate the amount of water on the surface?


No because socialism is evil.