This is an archive of CompuServe forum messages from 1985 to 1995, as saved in transcripts by John Foust.
Search Results (236 messages)
Jon I agree that the book is a good one. The picture on pages 84 & 85 are great but I come to a different conclusion. We are looking at a profile of the top part of the ocean basin with miles of basin to go. The basin actually rises…
Greetings Doug Ok lets look at global motion in relation to Antarctica >>From the viewpoint of Antarctica, I expect it is a case of ridges moving themselves away from Antarctica, primarily toward Australia, and minimally if at all toward Africa.>I am still trying to figure what you mean by "bowing".…
Don This thin strip of land along California brings up something. I have an observation that along the ring of fire there is a thin strip of crust all along this edge where I believe the moon was torn from the earth. This strip is obvious at california including baja,…
Doug Surface samples would not prove much. What we need to see are core samples to pass judgement on the origin of these apparent crustal remnants. Kamron
Doug >> Note that N. America has apparently been catching up with and "eating" the northern continuation of that ridge, though S. America is the faster moving continent.> I will simply assume that plateau is a basaltic eruption from the mid-Cretaceous superplume episode or some such.
Doug It would be great to have access to a database of core samples from around the world. Is there anything like this anywhere? >> As I said, there was one other article that remarked there was some continental material there
Hello Doug Can you fix this title…. should be Antarctica I am close here to finally communicating the point or the problem I see in the Mid Ocean Ridge shift faults. Thanks for bearing with me. >> The southeast Indian ridge I expect is doing no shifting along the ridge,…
#Antartica
Message #174995
Hello Doug Here comes the focus of the plate motion controversy (converging impossibilities) The motion of the Antarctic plate is demonstrated by the features present in the Mid Ocean Ridge that we find around it. We agree that the motion is directly away from the Australian continent on that side.…
Doug >> As stated before, I am aware of no motions that require a dramatic amount of plate compression to fit through a narrow "exit". In the Indonesian case we are talking about different subducting plates approaching from different directions – each plate is traveling in a mostly unified direction…
Doug >>If a ridge is active, I presume it has oriented itself to cut across the tension (if I pull cloth apart, the rip tends to cut across the pull), for the most part. That means there is little sideways tension to make the plates slide along the length of…
Doug >>The Scientific American of Oct 1993 article on large igneous provinces shows the Broken Ridge plateau and the 90-East ridge as being such. It implies the Kerguelen plateau and the Broken Ridge plateau formed from a single mantle plume. I take this to mean the plume formed a hot…
Don If all the sections of crust in the pacific are from separations of crust due to rifting then each in sequence was cut away by a different older rift from an earlier time. Any part carved off would be equidistant from the parent continent like the Cook Islands Manihiki…
Doug >>Another mechanism is described in the Scientific American of July 1989. After India rifted away from Africa and Antarctica, at the end of the Cretaceous it was blown apart by the arrival of a hotspot that announced itself by erupting the tremendous Deccan traps. A rift formed there and…
Don >> As I understand it, continental rock is very light and doesn't get sucked into subduction zones. That's how all those exotic terrannes John McPhee )"Assembling California") writes about got tacked onto the West side of Northern California.
Jon What I was wondering is how do the thicknesses of the Paleozoic and Mesozoic layers similar on each side of the Appalachian Mtns and the West African layers compare?
David >> I think the earth would be pulled from its orbit.
Greetings David >> I have been thinking about your catastrophe model.The tidal force of the sun right now is too weak to form continents, right. Using inverse cube law (applicable to tidal forces), the tidal strength of your object is only 1.25 times the current tidal force of the sun.…
Hello Jon Are there also granitic intrusions in the midst of the thrust faulting? How about the periodic crustal layers on each side of the Orogeny where it levels out…are they very different?
Doug >>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…
Doug >>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…
Greetings Don I am wondering about some of the other Plateau's out in the pacific that have larger areas and vertical sides, like the Manthiki, Ongtong Java, Solomon and others. Has there been drilling in these to determine if there is a geological crust there also like in the New…
>> I am not familiar with much of any river sedimentation-rate studies. Why do you call them "weir[d] studies"?
Hello Doug Oh I feel like I may be close here.. >> That is what I said, there may be sliding along the southwest Indian ridge, which in any case is not spreading fast, and/or sliding along those angled transform faults across that ridge. The Antarctic plate appears to me…
Welcome Michael This is an odd theory that some volcanoes are deep petroleum reservoirs that ignite and burn using the oxygen content in the earth. It might be interesting to investigate the smoke bellowing from volcanoes and see if it contains similar composition to burning petroleum and rock. I have…
Jon >> To see where things have been _happening_, you have to look to the west of the Americas, and to the east coasts of Asia and Africa, and the northern and eastern coasts of Australia. IOW, places where plates are moving along each other, or are being subducted. The…
>> No reason why they shouldn't fit together…all they've been doing is moving apart since the split, with a certain amount of erosion. Actually, the edges of the continental shelves (under water) of the continents are a better fit than the shorelines.> The "additional coast" I was talking about was…
I have seen an idealised rendering of layers along the deepest NW Pacific Trenches. I would expect a dense to fine stratification. What's your take on them? I remember reading of weir studies on the deposition rate of various rivers it of earth. The measurements of the time it took…
Doug >>You cannot mean the 3 plates meeting at the mid-oceanic ridges in the Indian Ocean since they are diverging, not converging; I figure you are worried about how Africa is almost surrounded by spreading ridges.>Imagine two plates are being pulled apart, but there is a third plate between them…
>> I see continental collisions as resembling car collisions. A light impact just crumples the bumper (shoves the sediments and older-rifting detritus on from the continental margins up on top). A heavier impact crumples the whole front end of the car (including the continental craton). > Granite is no more…
Jon >> I suspect your globe was on too small a scale for you to see how and why the continents aren't "perfect" fits anymore.
Kamron >>Howard has told you how th craton may not be compressed, but I am looking at the crust as a whole. As the slop (geosyncline) you have been talking about is pushed atop the craton, I expect the craton is forced down to gain buoyancy to support the mountains;…
Doug >> Yes, it is, in cases of fold mountains like the Appalachians and Himalayas. We can measure the gravitational differences (and I think the seismic wave distortions) caused by the "roots" of major mountain chains where the crust extends unusually deep into the lithosphere (shallow mantle), counterbalancing the weight…
Jim That is the location. If the charts i am rreferringto are accurate the erosion channels that radiate beyond the trench to the deeper parts of the basin have a wide gap between the coast and the sediment bed. This would eliminate the turbidity currents and the landslides associated with…
Doug >> It is not surprising if the sediments in the trenches are continually being pulled under with the subducting plate. The interesting question is how fast do the sediments accumulate vs. how fast are they subducted.
Howard >> The Atlantic closed (with continental collision) first, then opened, as it continues to do today. The collision occurred during Devonian time, creating the mountains of the eastern US. The Atlantic started opening up again in Triassic time.
Fold mountains
Message #172046
Thanks for the reference Jim I still not comfortable with the events that formed fold mountains. Looking at the current condition of the continental crust we find that almost all coasts have nearly vertical margins. They are vertical for thousands of meters to the basin and I would assume that…
Jim >> However, if they existed prior to the opening of the Atlantic Ocean in the Mesozoic, the rivers would have continued headward erosion and never been submerged. Also, erosion can take place in a sub-aqueous environment. River currents can extend long distances into the ocean. There are freshwater currents…
>> Remember that jog in the Mid-Atlantic Ridge near the coast of N. Brazil? It was once a far longer jog – after the N. Atlantic opened, S. America started away from Africa, with a _long_ transform fault making the then-long connection between the S. Atlantic ridge and the N.Atlantic…
Hello Ed >> This is similar to a question I always had about the inverted topography of the Ridge & Valley province of the Appalachians. The evidence in many cases is that the axes of the anticlines have eroded into valleys, and the axes of the synclines have been preserved…
Jon >> The faults move in directions dictated by plate motion. > The plates move in directions dictated by seafloor spreading.
Doug >> The ocean basins would have to be empty for a long time to let those canyons be cut into the continental shelf. If the ocean basins were empty only a short time and something rapidly dumped the entire oceans-full of water onto the continents, it would just flow…
>> The ridges were not so much like a single entity until the transform fault between N.Brazil and W.Africa mostly closed up,> apparently due to the faster spreading of the S. Atlantic ridge. There is still that jog in the fault we have discussed as a relic of the non-identity…
Jon I have a different process that may explain(some/many/all) deposits veins and ore intrusions. Well after the formation of the earth the molten materials stratified into layers of materials based on densities. These are just approximate guesses but the layers were in solid and liquid layers stratified by densities. Under…
David The plate bending along a straight front is very difficult. There being no cracks at all in the plate no folds to take up the stress. When you look at curved fronts both concave and convex the bending of the plate takes on an even more unbelievable characteristics. If…
David Good to hear from you. >>The reason straight line defects occur is because they relieve stress most efficiently, whether or not the motion is fast or slow.>Experiment, try to attach an adhesive label to a small ball whose diameter is about the size of the adhesive label. Try to…
Hi Don Thats one way all the ocean frozen at the poles and in the air. The basins could have been exposed down a lot further. Would have wiped out most or all of the ocean life though. These areas at the bottom of the shelf could have dropped down…
>> I am lost as to what you are talking about here. The area between the most eastern part of Brazil & Africa does have crimping that could also be a crunching of S. America moving upward. The Central American area looks like it is the product of a back…
So you have been there looking at that. I have not seen that and was wondering where the folded mountains were. Are you sure that all the tops are facing away from each other in matching pairs? When I have looked at the blocks closely I usually see them lined…
Yes thats it but they continue on down some go on down to 3,000 meters like there was no water down at that level for at least a short period of time. Kamron
Even what little I remember of the Appalachians is they are tilted crust and not folded crust as expected in the old mountains. I wonder if anybody else has studied them and could confirm this. Kamron
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