CompuServe Messages

Hi, Kamron– >> Get cars and line them up with spaces between them in neutral with the break off. now push the last one slowly forward at one inch a minute If we are moving at one inch a minute, it might take mountains on wheels to produce the big dents. Note that 5 mph is no big deal for colliding cars, but is quite significant to colliding battleships. The more the mass, the slower the collision needed to crumple things up. When you are talking continental masses, you do not need much speed to get a _lot_ of inertia. If you add some ongoing pulls of similar magnitude, that can only add to the crumpling. >> I like this description very much but I can't melt the granite over time yet. Because its like the cars..if it could slide it would slide easily once it got moving. Only your theory requires the granite to melt. Plate tectonics assumes solid flow, like the magnets popping one step down the line – just because it has moved, that does not help it make the next move. Only continued pressure, from continued pull and/or inertia (on a continental scale) can keep the solid flowing. >> >> There may be a seafloor-like underlayer to the colliding continents, which along with lithosphere may still be subducting out from under the collision point to keep pulling the continents together even after first impact; >> The forces at play to move the continental mass is much more than the Basin Mass. This underlayer is not the seafloor from oceans surrounding colliding continents – I am talking about _directly_ under the collision, where the lithosphere is also converging. Since the lithosphere is comparable in mass to the continents, and since it is denser and closer to the "escape hatch", it would be no surprise if the lithosphere from one of the plates took a dive even if the colliding continents on top do not. >> If the impact of the massive continent can be absorbed how could the puny Basin not get absorbed? Are you talking about the basin plate just south of India. I see no evidence that is subducting. I am saying the seafloor south of India might have started subducting (but I do not see that it has), and may yet start subducting (it is still early in that particular collision, as I said) near the coast of India. Continents in collision are too light to "want" to subduct, but let a following seafloor be confronted with the choice of crumpling and subducting, it is likelier to choose the latter. Once ocean crust is old enough to be cooler and denser than the mantle, it is just looking for any excuse to subduct. One caveat – if the pull that brought the continents together has ceased during the collision, there is less incentive for trailing seafloor to dive. >> May be if it was hitting something or vibrating apart you could effect the other side. You were just expressing surprise at continents crumpling in slow plate collisions, implying they should be ultimately rigid. They are not, as I have explained, but there is some rigidity that _might_ allow the pressure to be released at some remote place from the collision site in some cases. This does not seem to be the case where the Himalayas are concerned. >> How can you expect the granite structure to reform in time getting thicker like an earth worm when you let it go…shifting its atomic bonds and at the same time the crust has to fold to do the same thing? I am not sure I follow. Perhaps you are imagining an earthworm being stretched and then allowed to snap back to a thicker configuration – but this does not apply to collisions. Imagine instead the worm being thrown against a wall headfirst – it may thicken if the impact is direct enough. I assume by "crust" you meant only the rock atop the granite craton. If the undercarriage of a car crumples, why shouldn't the body also crumple? If the bumper crumples, the rest may or may not crumple – it all depends on the force and angle of collision, the point(s) of impact, and the construction of the car. >> Only if we are trying to discount all parts of current theories…some bending of layers obviously has occurred Whaddaya mean "we"? You are the one asserting any collisions took place within days, and trying to claim solid rock cannot bend/fold/crumple without melting or faulting even on the long time scales of plate tectonics. In your short time scale, your own assertions become correct – I very much doubt solid rock can fold so much within a week without very obvious melting and/or faulting. >> I think I see some shrinking in the pacific plate..if that is occuring then we need a bulging mountain area or ten of em. Seafloor might crumple if compressed, but as noted above subduction is more to be expected. If it crumpled, I do not expect the evidence to last long. Continental mountains can force down "roots" of light rock that will buoy the mountains up until the mountains erode. Seafloor material is already too heavy (except the youngest seafloor) to "float", and I expect it would just sink again soon after being uplifted, if indeed it does not all fold downwards instead of upwards. Any projection deeper into the lithosphere may be subject to being "dissolved" by that lithosphere (since it closely resembles the lithosphere in composition, or seemingly more likely, to starting a subduction. >> >> If there are pre-Carbonifereous fossils east of the Appalachians, I expect them to match African counterparts better than other N. American. >> I don't have a good grasp of why this seams so.. You had just asked for evidence that the east coast of the U.S. was once part of Africa. The collision of proto-N.America with proto-Africa which raised much of the Appalachians was about 300 million years ago, thus any older fossils east of the Appalachians should have been formed while that area was part of proto-Africa, and separated by an ocean from proto-N. America. Later fossils would not help in this matter, since both Africa and N. America were connected to the region after the collision. >> I don't see how the prominence and clarity of continental shelves could be joined and then separated and still be so cleverly disguised. I see you are a bit surprised by this also. The old continental craton edges would have met underneath what is now the Appalachians; burying the best evidence under mountains seems a good enough disguise for me. The only thing that was surprising me in this matter was a possible hint that the eastern seaboard did _not_ come from Africa, which proved not to be an intended implication. Don's mention of seafloor chunks caught up in the Green Mts. is probably about as much as one gets in the way of direct evidence for an earlier coastline thereabouts. He listed some fossil-bearing formations that seem to bear out my "prediction", provided they are old enough; it seems there is better fossil evidence for some coastal exchanges between N. America and Europe. It seems we traded Scotland for coast from east Newfoundland south to maybe RI; they tried to run off with Greenland also, but got caught. >> Are there organized tours where we get eyes on discussion of geological sites? My college alumni assoc. very occasionally offers me such a chance in southern Calif., but I have never been in a position to accept. Now that I am moving back (likely by April), we'll see… Rockhound clubs occasionally offer such field trips, though they are more often interested only in collecting sites. The trouble is finding such things when you are traveling. That is surely part of why there is much interest in a database of clubs. Anyone out there know some interesting field trips with a geologist for a tour guide? –Doug