(December 12, 2008 at 9:22 am)Purple Rabbit Wrote: You introduce new arguments like higher and lower density but present no evidence for it. Furthermore it seems to me that in the model you present the density alone is not decisive but the total mass is. It's the total pressure on the mantle that's relevant (assumed that there's no upward trust from convection streams in the mantle), i.e. the thickness of the crust in combination with the density of the crust is critical. Furthermore a water column of 10 km does add considerable pressure to the mantle on top of the weight of the crust. You can't neglect it in your model.
Sorry purple, you're right about the evidence of course. I've just learned that with Daystar there is little point in presenting any since he doesn't bother to read it.
Anyway, the water column does of course add something (and one would assume the column to be about 1/3 of the thickness of the oceanic crust, as water is about 1000 Kg per cubic meter), but that still does not mesh with the idea of very shallow oceans pushing down and causing new mountains to form. Further, this model of isostasy is not my model, it's just one that fits right now with seismic data.
Basically, http://geology10.com/files/lecture13/htm...file16.htm
More in depth, but taken from a research article database, so let me know if you can't access them.
One
Two
Any problems with these links, let me know, and I'll try to figure out some way to get them to you. I think they are on a secure server, so there may be issues.