The different elements found in each layer of the earth's interior?

or:The different elements found in each layer of the earths interior?or:Mines have been dug to a few thousand feet depth. One hole in Russia was dril

or:The different elements found in each layer of the earth's interior?

or:Mines have been dug to a few thousand feet depth. One hole in Russia was drilled to 7.6 miles: en.wikipedia.org/wiki/Kola_Superdeep_Borehole Most of what we think we know about what's under our feet comes from echolocation done for oil exploration. I have no information about depth or reliability of that data, except that it only pertains to structure, not chemical makeup. \"Layers\" are still imaginary. We know that there is something down there that bends sound waves, but we have no clue about what it is.

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