On Wed, Jun 17, 2009 at 12:58 AM, <[email protected]> wrote: > In reply to David Jonsson's message of Tue, 16 Jun 2009 17:36:11 +0200: > Hi, > [snip] > >Wait a moment. The magma is hot becasue it is pressurised. When you pick > it > >up to earth it will expand and cool. > [snip] > Volcano. >
OK, I have to admit I haven't studied the magma but only the crust. And it surprises me much that the magma has an adiabatic gradient of only 0.3 K/km. How was that calculated? Admit that the crust will cool if picked up. David
