Another possible method of uplift is delamination of the subducted farallon slab from the underside of the lithospheric mantle.  The release of the dense slab would cause the  crust to "pop up".  The slab would then be replaced by less dense asthenosphere.  Geochemistry shows that not all of the mantle was removed from the base of the crust, is a partial delamination enough to cause the uplift?  This is one of the questions that are under debate.