cdaf@iuvax.UUCP (12/13/86)
In article <648@bath63.ux63.bath.ac.uk> ma_jpb@ux63.bath.ac.uk (Bennett) writes: >[...] > Given we can work out the kinetic >energy of the plate, we can calculate the height of the mountains this would >raise if converted to potential energy with 100% efficiency. There seems to be a limit to the height of the mountains. If I remember correctly from freshman physics, Everest is close to the theoretical height of a mountain. This is because the intense pressure sustained by the rock supporting the mountain has brought it to nearly melting temperatures. Obviously this is only applicable to the rock deep inside the base region of the mountain, upon which most of the stress falls. I'm lead to wonder whether a molten inner base of a mountain (due to stress) would cause the mountain to collapse, or if the molten portion could be successfully contained by the less-strained base of the mountain? -charles -- All that we may see or seem | Snail : Box 1662 Bloomington, In. 47402-1662 Is but a dream within a dream | ATT : (812) 339-7354 - [I don't know] | USEnet: cdaf@iuvax.csnet | iuvax!cdaf (can anyone help me?) | BITNET: BCHC901@INDYCMS
bob@uhmanoa.UUCP (Bob Cunningham) (12/16/86)
> There seems to be a limit to the height of the mountains...
The principle is correct, but the details get a little complicated...
Under pressure and high temperatures, most minerals undergo phase changes
---effectively becoming different minerals---that increase their ability to
withstand pressure and temperature. Although obviously rare,
carbon-to-diamond is one almost everybody knows about. Less well known are
minerals like perovskite that the various high-pressure labs around the
world have only recently been able to produce by duplicating
the extreme pressures and temperatures deep in the earth.
That Mt. Everest isn't near the theoretical limits of height for a mountain
should be obvious. There are other mountains that---from their base to
peak---are higher (and there are mountain peaks further from the earth's
center as well). Everest is just the mountain with the most elevation
above the earth's geoid (or, if you prefer a less precise term: above sea
level).
--
Bob Cunningham
bob@hig.hawaii.edu