CompuServe Messages

Hi, Kamron– I am not sure that pressure between the plates is the only string in the bow of the "push" theorists – perhaps the asthenosphere is less than frictionless and allows some coupling between the convection in the mantle and the lithospheric plate, perhaps mountain roots project into the mantle and give it something to push against, and so on. I do not know which of these are part of the canon. The pressure between plates need not be of the sort that explodes as magma fountains. Consider water freezing in cracks to split rocks; I'll grant magma probably does not expand on freezing, but note that not all pressures are prone to explosions, nor must they become ineffective if there is an escape open. I'd be interested to hear exactly what mechanisms the "push" theorists have worked out. It is not a "stretch" to jump from moving plates to subduction. If I am convinced by radio-dating, paleomagnetism, hot spot relative-motions, etc. that the sea floor is moving, it is quite straightforward to ask where it goes when it meets another plate or continent and decide the "sonar" image we see on seismographs is the answer (bearing in mind no other answer offers anything approaching this quality of evidence). Nowadays, anything contradicting plate tectonics might indeed get ignored for a while if it is not too spectacular; scientists are human. But alternate theories, including some rather like yours, were present before plate tectonics became the standard-bearer. When the youth of the ocean floor was detected, simultaneous resurfacing must have been an obvious contender to plate renewal/movement/destruction, and must have received plenty of attention. In that conflicting state, only evidence, not stodgy following of establishment theory (which if anything favored the resurfacing-everywhere theory), can cause a new consensus to form among true scientists despite their human failings. If a scientist now comes up with solid evidence (not just theories) leading away from plate tectonics, that person will indeed face considerable risk to his/her career by pressing the battle, but also considerable gains if proven right. Many fields of science show frequent overturns of consensus theories, thus I know any institutional inertia can be overcome sooner or later. –Doug