arc Posted February 15, 2015 Author Posted February 15, 2015 It also means that the geodynamics community will seriously have to reevaluate the way they model subduction. I've known that for several years and the entire 20 pages of this thread. Yes, there is a rift in the middle of the ridge. That is an extensional feature because the two halfs of the plate are drifting apart. I think we agree on that. However, your attempting to fit this into the context of your model is reminiscent of a child attempting to force a square peg through a round hole. That there is maybe your problem, you haven't figured out the correct shapes of the problems you're dealing with. The total lack of simple cause and effect, the current models inability to make predictions of observations. My model again has delivered a accurate, and more importantly, simple explanation to a geologic phenomenon. Occam's Razor wins again. I have done some of my own research looking at the anisotropy in the subslab asthenospheric mantle and have found independent evidence that the slab is decoupled from the asthenosphere. Therefore, the existence of this thin decoupling channel is extremely interesting and provides a plausible mechanism for me to explain my results. WOW! That looks to me as a "Hail Mary pass" to win your loosing argument. Great, more "Guess whats in the box geophysics" again. It's a basin developing between two halves of a once combined pressure ridge. It will grow wider and resemble the basin that was there before the Plio-Pleistocene mountain building period. All mountain ranges have the same simple cause, crustal compression, It is obvious yet some of the most committed to the standard model will argue the most tenuous explanations to avoid what they can see with their own two eyes. My model shows that simple surface observations using reliable data collected from multiple sets of the Himalayan and Andean ranges and the simple application of Occam's Razor lead to fruitful results.
studiot Posted February 15, 2015 Posted February 15, 2015 It's a basin developing between two halves of a once combined pressure ridge. It will grow wider and resemble the basin that was there before the Plio-Pleistocene mountain building period. All mountain ranges have the same simple cause, crustal compression, It is obvious yet some of the most committed to the standard model will argue the most tenuous explanations to avoid what they can see with their own two eyes. Crustal material falls into two distinct and different material types that are easily recognisable. Oceanic crust and Continental crust. Orogeny can be the result of single or episodic magmatic upwelling It can also be the result of penetrant impact. This refers to the shear generated by pressure from a sharp object such as the Indian plate, which is small compared to the Eurasian plate it is pushing into. Think about pushing into your carpet with your finger. You will generate ruggles, but not by compression. Occam also needs to consider the age sequence and composition of the rocks on the bed of the Atlantic which definitely suggest and fit with epidsodic upwelling of mantle material as opposed to compression of continental crust.
billiards Posted February 15, 2015 Posted February 15, 2015 I've known that for several years and the entire 20 pages of this thread. You "know" that there are problems with plate tectonics in the same way that a layman knows there is a problem with unifying quantum physics with gravitation. You know there are problems but you don't understand quite what they are. You're exactly the same as any crackpot who claims to have derived the theory of everything, but who can't do matrix multiplication or appreciate the power and utility of the existing theories. That there is maybe your problem, you haven't figured out the correct shapes of the problems you're dealing with. The total lack of simple cause and effect, the current models inability to make predictions of observations. Hahahahahahhahahahaha. The irony, it's killing me, please stop! My model again has delivered a accurate, and more importantly, simple explanation to a geologic phenomenon. Occam's Razor wins again. Hahaha! Oh dear! This is too much. WOW! That looks to me as a "Hail Mary pass" to win your loosing argument. Great, more "Guess whats in the box geophysics" again. Arc, the detachment zone really has no weight on this debate. Did you notice that I didn't comment at all on your model? Not everything is about you and your stupid model you know. It's a basin developing between two halves of a once combined pressure ridge. It will grow wider and resemble the basin that was there before the Plio-Pleistocene mountain building period. All mountain ranges have the same simple cause, crustal compression, It is obvious yet some of the most committed to the standard model will argue the most tenuous explanations to avoid what they can see with their own two eyes. You obviously haven't read the Parsons and Sclater (1977) paper have you? Also, you obviously have never studied any structural geology because if you had you would realise that normal faults just shouldn't be there if the ridge was formed by compression (it should be thrust faults -- which would be reactivated under extension). I have explained several times why you are wrong here, but it just doesn't seem to register. Would you like me to explain it again? My model shows that simple surface observations using reliable data collected from multiple sets of the Himalayan and Andean ranges and the simple application of Occam's Razor lead to fruitful results. No I'm afraid not. Also, playing with razors is not advisable for those that do not know how to use them safely, you've cut yourself several times.
Essay Posted February 16, 2015 Posted February 16, 2015 #1: It's a basin developing between two halves of a once combined pressure ridge. .... #2: All mountain ranges have the same simple cause, crustal compression.... #3: "We can clearly see now that there is two halves to a once single Atlantic ridge." -from post 399. Do volcanoes fit into that category (#2), which has the "same simple" cause? === About #3 (where "we can clearly see" -re post 399) and those final two magnified cross-sections of the MAR; for each image, please list the "distance, km" that roughly describes each edge of which "basin" you're talking about in #1. ~
arc Posted February 16, 2015 Author Posted February 16, 2015 (edited) Crustal material falls into two distinct and different material types that are easily recognisable. Oceanic crust and Continental crust. Orogeny can be the result of single or episodic magmatic upwelling It can also be the result of penetrant impact. This refers to the shear generated by pressure from a sharp object such as the Indian plate, which is small compared to the Eurasian plate it is pushing into. Think about pushing into your carpet with your finger. You will generate ruggles, but not by compression. Occam also needs to consider the age sequence and composition of the rocks on the bed of the Atlantic which definitely suggest and fit with epidsodic upwelling of mantle material as opposed to compression of continental crust. Yes, point taken. That is why I referred to them as ranges. http://en.wikipedia.org/wiki/Volcanic_belt "Volcanic belts are similar to a mountain range, but the mountains within the mountain range are volcanoes, not actual mountains that are formed by faulting and folding by the collision of tectonic plates." I live at the edge, if not really within the cascade range that runs down the west coast of the U.S. It runs from N. California to British Columbia and is a very volcanically active range as it is part of the Pacific ring of fire. The crust was first broken in a extension event, and then pushed together during an episode of compression, bulldozing these now broken sections together, one onto the next, forming a range of overlapping slabs of crust. A person can drive up the Columbia River gorge that cuts directly through this range and view these tilted slabs. It's hard to see but there is a semi-truck on the highway just above the river to the left, just below and right of that clearing in the trees, just for a sense of scale of this slab. http://en.wikipedia.org/wiki/Cascade_Range "When the Cascades started to rise 7 million years ago in the Pliocene, the Columbia River drained the relatively low Columbia Plateau. As the range grew, erosion from the Columbia River was able to keep pace, creating the gorge and major pass seen today. The gorge also exposes uplifted and warped layers of basalt from the plateau." There's that Plio-Pleistocene mountain building period again! That thing really gets around! So, our volcano's here along this range are undoubtedly indebted to a period of extension and then compression to fracture this basaltic crust and create the many easy avenues for the volcanic processes to rise through. And below we see that the extension occurred in the presiding Miocene when the Basin and Range Province just to the south and east of the Cascades was actively extending. http://en.wikipedia.org/wiki/Columbia_River_Basalt_Group "During the middle to late Miocene epoch, the Columbia River flood basalts engulfed about 163,700 km2 (63,200 sq mi) of the Pacific Northwest, forming a large igneous province with an estimated volume of 174,300 km3 (41,800 cu mi). Eruptions were most vigorous from 17–14 million years ago, when over 99 percent of the basalt was released. Less extensive eruptions continued from 14–6 million years ago." Image above provided by Victor Camp and Martin Ross. "Occam also needs to consider the age sequence and composition of the rocks on the bed of the Atlantic which definitely suggest and fit with epidsodic upwelling of mantle material as opposed to compression of continental crust." Well, that massive extensional event in the Miocene that created the Basin and Range Province is caused by the mantle's outward displacement. It would involve every divergent boundary on the planet. The flow in the Atlantic boundary could possibly be greater but considering that boundary had no convergent trenches within the surrounding basin would guarantee a crushing of the boundary anyway when the mantle subsided. What would produce this one time "episodic upwelling" event along the entire 16,000 km boundary that you elude to? That is the real killer in all this, it occurred the whole length of the boundary. It would need to be accounted for everywhere no doubt. My model could accommodate a increase of magmatic boundary infill during that prior period of the Miocene, having the mantle already in overdrive is what put that extra boundary material in place for the mountain building to come. I really don't see a problem with it other than getting the exact timing right. And why other boundaries like the Pacific would not have out paced its volume and have even larger ridges themselves. You "know" that there are problems with plate tectonics in the same way that a layman knows there is a problem with unifying quantum physics with gravitation. You know there are problems but you don't understand quite what they are. You're exactly the same as any crackpot who claims to have derived the theory of everything, but who can't do matrix multiplication or appreciate the power and utility of the existing theories. Hahahahahahhahahahaha. The irony, it's killing me, please stop! Hahaha! Oh dear! This is too much. Arc, the detachment zone really has no weight on this debate. Did you notice that I didn't comment at all on your model? Not everything is about you and your stupid model you know. You obviously haven't read the Parsons and Sclater (1977) paper have you? Also, you obviously have never studied any structural geology because if you had you would realise that normal faults just shouldn't be there if the ridge was formed by compression (it should be thrust faults -- which would be reactivated under extension). I have explained several times why you are wrong here, but it just doesn't seem to register. Would you like me to explain it again? No I'm afraid not. Also, playing with razors is not advisable for those that do not know how to use them safely, you've cut yourself several times. Never mind. If you want to challenge my model on this you would need to show how this proto basin occurred between two 2 km high ridges simultaneously over the entire length of the Mid Atlantic Ridge, 16,000 km long through multiple fracture zones in two hemispheres, adjacent to four separate continental plates, while at the same geologic moment the Himalayas and the Andes and many smaller mountain ranges around the globe were also being created. The uniformity of this requires a simultaneous global scale mechanism . . . . . Just thought I'd mention that. Do volcanoes fit into that category (#2), which has the "same simple" cause? === Yes as I described above. I think they are creatures of opportunity looking for a weakness in the crust to take advantage of. Extended and then compressed ranges give opportunity to magma from below. === About #3 (where "we can clearly see" -re post 399) and those final two magnified cross-sections of the MAR; for each image, please list the "distance, km" that roughly describes each edge of which "basin" you're talking about in #1. ~ Around 9 km between the base of the two ridges, if I understand you correctly. I took quite a few cross sections to get a good summit to summit measurement, on some it was hard to tell one side or the other for the real summit. They weren't distinct enough to identify, lower with two possible choices for ridges. So the two you see posted have nearly the same summits and basin distances. You would be surprised how the cross sections don't resemble the place you took them from. I would recommend everyone try Geomapp themselves, its a lot of fun. Edited February 16, 2015 by arc
Essay Posted February 16, 2015 Posted February 16, 2015 Around 9 km between the base of the two ridges, if I understand you correctly. I took quite a few cross sections to get a good summit to summit measurement, on some it was hard to tell one side or the other for the real summit. They weren't distinct enough to identify, lower with two possible choices for ridges. So the two you see posted have nearly the same summits and basin distances. No, I meant where ...or between what two numbers (km on the x axis) are you finding that ~9 km basin?
arc Posted February 16, 2015 Author Posted February 16, 2015 No, I meant where ...or between what two numbers (km on the x axis) are you finding that ~9 km basin? I sampled at 90 degrees to the boundary axis between those two lines.
Essay Posted February 16, 2015 Posted February 16, 2015 (edited) I sampled at 90 degrees to the boundary axis between those two lines. How can I be more clear? On the x axis there are numbers such as 10, 20, 30, 40, etc., or 20, 40, 60, 80, etc., labeled as "distance, km," divided into increments of one km, or two km, respectively for each graph. Between which two numbers (in km), or between which two values (in km), are you seeing the basin? === For each of the two cross sections: Please pick two numbers (in km) that signify the right and left margins for the basin you mentioned. === So, that would be four numbers total ...or you could just do one picture, with two numbers (from the x axis) that indicate the right and left 'edges' of your basin. === For instance, you mentioned 9 km for a basin. In the first picture, between about 20 and 29 km, there is a basin-like shape. If this is what you're talking about, please explain that: 'between 20 and 29 km is a low flat area,' or something like that. So the two numbers for that first picture/graph would be 20 & 29, right? ...or please explain otherwise. === So.... Between what two numbers, in the second picture/graph, are you describing a basin? ~ Edited February 16, 2015 by Essay
arc Posted February 16, 2015 Author Posted February 16, 2015 (edited) Below are some additional cross sections along the ridge shown above. And take into consideration that their data has also been laterally compacted and the actual basin that is developing between the ridges is much wider than shown. For example in the image below the ridge on the right is over 2 km high while the basin between the ridge is around 9 km wide. The basin therefor would need to be shown as being more than 4 times wider to be in proper scale to the ridge elevation. We can clearly see now that there is two halves to a once single Atlantic ridge. .Atlantic ridge 50km 1.5.png .Atlantic ridge 50km 1.6.png Sorry, you could us the quote button. I was referring to this one directly. I think its basin metric is self explanatory. Around 9 km from 19 or so to 28. I wasn't BTW measuring the "widest areas" I wasn't directly referring to this one's "basin" measurement. I was more interested in getting a reasonable ridge to ridge measurement and this one was clear enough to include. It was obviously taken where the floor narrowed. I would assume when a boundary is crushed and ruptured vertically, the following resumption of divergent activity would result in debris slides into the center as it widens. We know by the scale these slopes are not this steep. Did this answer your question? Edited February 16, 2015 by arc
Essay Posted February 16, 2015 Posted February 16, 2015 Two numbers, arc. ...to echo studiot's frustration from the previous page. Thanks, at least, for choosing 19 & 28 (instead of 20 & 29) from the first example; as you could tell, that's what I thought you were talking about, since we seem to agree on the numbers fairly closely. I'm not trying to quibble about small differences, just making sure we're looking at the same feature when you describe something. Can you do the same for the second picture also? Are we talking about the main dip near the middle, at around 50-55 km, rather than the dip around 100 km? ...but of course, please pick your own two numbers. ~
studiot Posted February 16, 2015 Posted February 16, 2015 (edited) arc If you want to challenge my model on this you would need to show how this proto basin occurred between two 2 km high ridges simultaneously over the entire length of the Mid Atlantic Ridge, 16,000 km long through multiple fracture zones in two hemispheres, adjacent to four separate continental plates, while at the same geologic moment the Himalayas and the Andes and many smaller mountain ranges around the globe were also being created. Thank you for the nice pictures, but again a digression. Do you really think 200 million years is simultaneous? Studiot Occam also needs to consider the age sequence and composition of the rocks on the bed of the Atlantic which definitely suggest and fit with epidsodic upwelling of mantle material as opposed to compression of continental crust. This short line requires full and detailed consideration as it is the basis of the conventional history of ocean floor spreading. Please note there is almost overwhelming support evidence behind this part of the story. So much so that this now forms part of the high school curriculum. http://www.earthlearningidea.com/PDF/198_Atlantic_opening.pdf Here is the conventional history made from substantial bottom sampling. I don't think it can be fairly called anything approaching simultaneous, even on a geological timescale. My pic is only greyscale and not up to your standards, but it shows the essential information clearly. Edited February 16, 2015 by studiot
billiards Posted February 16, 2015 Posted February 16, 2015 (edited) Never mind. The problem for you is I do mind. I mind very much when I see someone get it so badly wrong. You still haven't even acknowledged the two very crucial points I have made: • The Parsons and Sclater (1977) thermal model to explain sea floor bathymetry (this is why you get the "mountain range" at the mid-Atlantic ridge) • The complete lack of compressional faulting on the ocean floor (i.e. no evidence for past compression -- proving your model is wrong) Those above points are real science ... PLEASE address them ... Your tactics are to shift the goal posts ... If you want to challenge my model on this you would need to show how this proto basin occurred between two 2 km high ridges simultaneously over the entire length of the Mid Atlantic Ridge, 16,000 km long through multiple fracture zones in two hemispheres, adjacent to four separate continental plates, while at the same geologic moment the Himalayas and the Andes and many smaller mountain ranges around the globe were also being created. The standard model explains all the features you have mentioned easily (as I have already posted): • The valley is an extensional feature caused by the two plates drifting apart. It' a simple consequence of structural geology. You also have the same feature in the Pacific spreading ridges, the East African spreading ridge, etc. etc.. in fact generally you get basins wherever you get extensional tectonics. Now please explain why there are no compressional faults on the ocean floor, according to your model. Edited February 16, 2015 by billiards
arc Posted February 17, 2015 Author Posted February 17, 2015 OK, starting next Friday the 20th I'll be absent, won't be around again until March 1st or so. Two numbers, arc. ...to echo studiot's frustration from the previous page. Thanks, at least, for choosing 19 & 28 (instead of 20 & 29) from the first example; as you could tell, that's what I thought you were talking about, since we seem to agree on the numbers fairly closely. I'm not trying to quibble about small differences, just making sure we're looking at the same feature when you describe something. Can you do the same for the second picture also? Are we talking about the main dip near the middle, at around 50-55 km, rather than the dip around 100 km? ...but of course, please pick your own two numbers. ~ You have something against 19 and 28? Your guess is as good as mine. Yes 50-55 km is correct. I tried to center on the ridge every time, some are off a little bit though. Thank you for the nice pictures, but again a digression. Do you really think 200 million years is simultaneous? This short line requires full and detailed consideration as it is the basis of the conventional history of ocean floor spreading. Please note there is almost overwhelming support evidence behind this part of the story. So much so that this now forms part of the high school curriculum. http://www.earthlearningidea.com/PDF/198_Atlantic_opening.pdf Here is the conventional history made from substantial bottom sampling. I don't think it can be fairly called anything approaching simultaneous, even on a geological timescale. My pic is only greyscale and not up to your standards, but it shows the essential information clearly. atlantic1.jpg My point is the same as yours actually. I do not diverge from what you say above, that the sections have grown at different rates and show the typical progression of plate tectonic movement. Its that if the figure of 25 mm a year of Atlantic Mid-Ocean Ridge infill is accurate then by simple deduction 2 million years puts those two opposing ridges at the center of the boundary where the actual plate sections are parting ways. I find it reasonable to imagine that if the mantle could subside it would load the entire boundary as simultaneously as would be geologically possible. That 2 million years journey back in time puts those two opposing halves together, centered on the boundary during the Pleo-Pleistocene mountain building period that I have documented previously. The Himalayan and Andean mountain building required an extended period of building an increased level of gravitational potential energy prior to the movement that raised those ranges so quickly 2 MYA. The combined force of four continents would be bearing down at the same time on the Atlantic boundary. This would leave a rather precise marker in the form of a deformation of the boundary from that energy level. Add to this, these mountain building episodes occur at 30 million +/- year intervals. The normal mode of operation for this model would be what we have currently, a slow divergent boundary infill rate that this model would expect to vary over time to allow the boundary infill to be a driver of subduction. Gradually building GPE as the mantle subsides and then to replace it when it displaces outward again. The problem for you is I do mind. I mind very much when I see someone get it so badly wrong.You still haven't even acknowledged the two very crucial points I have made:• The Parsons and Sclater (1977) thermal model to explain sea floor bathymetry (this is why you get the "mountain range" at the mid-Atlantic ridge)• The complete lack of compressional faulting on the ocean floor (i.e. no evidence for past compression -- proving your model is wrong)Those above points are real science ... PLEASE address them ...Your tactics are to shift the goal posts ...The standard model explains all the features you have mentioned easily (as I have already posted):• The valley is an extensional feature caused by the two plates drifting apart. It' a simple consequence of structural geology. You also have the same feature in the Pacific spreading ridges, the East African spreading ridge, etc. etc.. in fact generally you get basins wherever you get extensional tectonics.Now please explain why there are no compressional faults on the ocean floor, according to your model. "Now please explain why there are no compressional faults on the ocean floor, according to your model." I'll have to look into that. I'll get back to you. When I look at that boundary I see a structure that endures tremendous hardship as it slowly jacks N. America over the top of what's left of the Farallon Plate as the mantle cycles. How does the standard model accomplish that? I thought this was rather interesting; Mantle thermal pulses below the Mid-Atlantic Ridge and temporal variations in the formation of oceanic lithosphere Enrico Bonatti*†‡, Marco Ligi*, Daniele Brunelli*†, Anna Cipriani‡, Paola Fabretti*, Valentina Ferrante*†, Luca Gasperini* & Luisa Ottolini§ * Istituto di Scienze Marine, Geologia Marina, CNR, Via Gobetti 101, 40129, Bologna, Italy † Dipartimento di Scienze della Terra, Universita` “La Sapienza”, Piazzale Aldo Moro 5, 00187, Rome, Italy ‡ Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA § Istituto di Geoscienze e Georisorse, Sezione di Pavia, CNR, Via Ferrata 1, 27100, Pavia, Italy "A 20-Myr record of creation of oceanic lithosphere at a segment of the central Mid-Atlantic-Ridge is exposed along an uplifted sliver of lithosphere. The degree of melting of the mantle that is upwelling below the ridge, estimated from the chemistry of the exposed mantle rocks, as well as crustal thickness inferred from gravity measurements, show oscillations of ,3–4 Myr superimposed on a longer-term steady increase with time. The time lag between oscillations of mantle melting and crustal thickness indicates that the solid mantle is upwelling at an average rate of ,25mmyr, but this appears to vary through time." " the solid mantle is upwelling" That would be the displacing mantle - but their close. It sure sounds like that "Plate Tectonic Mechanism" some crazy guy on SFN is talking about.
Essay Posted February 17, 2015 Posted February 17, 2015 You have something against 19 and 28? Your guess is as good as mine. Yes 50-55 km is correct. I tried to center on the ridge every time, some are off a little bit though. As you can also see the rift or divergent center has a basin developing between the two opposing ridges. This proto-basin with the divergent boundary at its center maintains this configuration consistently along the entire Mid-Atlantic Ridge mountain range. These are a series of images of the same location at gradually increasing definition. Atlantic ridge 50km 5.1.png Atlantic ridge 50km 4.1.png Atlantic ridge 50km 3.1.png Atlantic ridge 50km 2.1.png Atlantic ridge 50km 1.5.png Below are some additional cross sections along the ridge shown above. And take into consideration that their data has also been laterally compacted and the actual basin that is developing between the ridges is much wider than shown. For example in the image below the ridge on the right is over 2 km high while the basin between the ridge is around 9 km wide. The basin therefor would need to be shown as being more than 4 times wider to be in proper scale to the ridge elevation. We can clearly see now that there is two halves to a once single Atlantic ridge. .Atlantic ridge 50km 1.5.png .Atlantic ridge 50km 1.6.png ...symmetry can develop on many levels; hint, hint, hint. Firstly, your “proto-basin with the divergent boundary at its center” is more analogous to a caldera, rather than to a basin …especially for the sort of geologic-scale basins you frequently mention, which don’t form this way. A cross section of the mid-Atlantic Ridge (MAR) looks like a cross section of the typical volcano, with its caldera appearing as a low basin in the center, surrounded by steep jagged peaks that then slope away to each side. But secondly, your “proto-basin with the divergent boundary at its center” should be located at the “0” km point, on the x axis of “distance, km,” shouldn’t it? The “distance, km” is the distance away from the spreading center, or the “proto-basin with the divergent boundary at its center,” which the previous pictures of the MAR zoomed in on, isn’t it? I’d expect that blue valley, in the center of those earlier pictures, is (half) shown at the far left of these two cross-sections, both marked at between 3100 and 3400 meters below sea level. I like the way you zoomed in on the MAR, but [unless I'm mistaken about how you "tried to center on the ridge every time] ...when you transitioned to cross sections, I think your graphics got shifted east, relative to the center of the MAR. The “basin” and the peaks that you’re looking at are normal topography, for each side of a rift valley, as shown widely on the internet, istm: …just add some sediment onto the low spots, on one side of the MAR, and it would look more like those cross sections you have. Do the points about buoyancy and subsidence, in billiard’s post #393 & 396, not make sense to you; or perhaps it is just that those points don’t make sense in your model? === ...and thirdly: Certainly, “more than 4 times wider” is true, but I wonder if you see why it must be over 5 times wider; or indeed 7.5 times wider? ~
billiards Posted February 17, 2015 Posted February 17, 2015 "Now please explain why there are no compressional faults on the ocean floor, according to your model." I'll have to look into that. I'll get back to you. I realised that out of context this phrase could easily be misinterpreted. Let me rephrase: If (according to arc's model) the Atlantic has experienced periods of compression which formed the ridge, then where are all the compressional faults? I look forward to the creative reply. When I look at that boundary I see a structure that endures tremendous hardship as it slowly jacks N. America over the top of what's left of the Farallon Plate as the mantle cycles. How does the standard model accomplish that? I cannot possibly comment on this as your description is very unclear. Perhaps your observational skills are not up to scientific standards? Perhaps it's just a case of severe confirmation bias? I thought this was rather interesting; Mantle thermal pulses below the Mid-Atlantic Ridge and temporal variations in the formation of oceanic lithosphere Enrico Bonatti*†‡, Marco Ligi*, Daniele Brunelli*†, Anna Cipriani‡, Paola Fabretti*, Valentina Ferrante*†, Luca Gasperini* & Luisa Ottolini§ * Istituto di Scienze Marine, Geologia Marina, CNR, Via Gobetti 101, 40129, Bologna, Italy † Dipartimento di Scienze della Terra, Universita` “La Sapienza”, Piazzale Aldo Moro 5, 00187, Rome, Italy ‡ Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA § Istituto di Geoscienze e Georisorse, Sezione di Pavia, CNR, Via Ferrata 1, 27100, Pavia, Italy "A 20-Myr record of creation of oceanic lithosphere at a segment of the central Mid-Atlantic-Ridge is exposed along an uplifted sliver of lithosphere. The degree of melting of the mantle that is upwelling below the ridge, estimated from the chemistry of the exposed mantle rocks, as well as crustal thickness inferred from gravity measurements, show oscillations of ,3–4 Myr superimposed on a longer-term steady increase with time. The time lag between oscillations of mantle melting and crustal thickness indicates that the solid mantle is upwelling at an average rate of ,25mmyr, but this appears to vary through time." " the solid mantle is upwelling" That would be the displacing mantle - but their close. It sure sounds like that "Plate Tectonic Mechanism" some crazy guy on SFN is talking about. More confirmation bias and less hard thinking. These pulses have been observed elsewhere ... (I don't have the references to hand, though it might be interesting to dig them out) ... Interestingly, this is actually evidence against your hypothesis. Your hypothesis requires oceanic crust formation to stop and start. However, these studies clearly show that oceanic crust formation is constantly ongoing.
studiot Posted February 17, 2015 Posted February 17, 2015 (edited) My point is the same as yours actually. I do not diverge from what you say above, that the sections have grown at different rates and show the typical progression of plate tectonic movement. Its that if the figure of 25 mm a year of Atlantic Mid-Ocean Ridge infill is accurate then by simple deduction 2 million years puts those two opposing ridges at the center of the boundary where the actual plate sections are parting ways. Not exactly my point. 2 millionyears v 200 million years is a big difference. If you look closely at my four maps you can see that two hotspots, roughly the presentday Azores and Tristan-Walvis hotspots , (Nos 1 and 42 here) http://en.wikipedia.org/wiki/File:Hotspots.jpg Doming up under the landmass of the 200MY BP starting the North Atlantic and South Atlantic oceans respectively. At this time there was no oceanic basin , ridge or floor. The spreading of the ocean floor, the building of the ridge and the eventual joining of the two oceans can be followed over the first three maps for 150 MY. Note that the northen end to this ridge between Greenland and Canada becomes a side spur and the ridge branches and extends further north in th last (50MY) map with the upwelling of the modern Icelandic hotspot. You have not fully appreciated the implications of the regular increase in age of the ocean floor rocks from as distance increases both east and west of the ridgeline. If, as you contend, the ridge is the result of pre-existing being thrust up under pressure from both sides (you cannot have compression from one side only) then, by definition of pre-existing, the ridge would be older rock. However some of the ridge rock is so young as to be dated 0 Y. If, you prefer to contend that compression led to the original upwellings then that upwelling cannot have been the present day ridge material because even the space it now occupies did not exist 200 MY BP, let alone the material to occupy it. Let me take this opportunity to wish you wwell in your break and to thank you for focusing attention on an interesting subject. I do not endorse this site, but have you come across the continually expanding theory? (Not expansion/contraction cycles like yours) http://www.expansiontectonics.com/page3.html Edit today was pancake day (Shrove Tuesday). I don't know if you have ever cooked pancakes, but you can see the doming produced by hot upwelling beautifully illustrated in the pancake pan as the hot air bubbles up from underneath. Edited February 18, 2015 by studiot 1
billiards Posted February 17, 2015 Posted February 17, 2015 If, as you contend, the ridge is the result of pre-existing being thrust up under pressure from both sides (you cannot have compression from one side only) then, by definition of pre-existing, the ridge would be older rock. However some of the ridge rock is so young as to be dated 0 Y. An excellent point.
studiot Posted February 18, 2015 Posted February 18, 2015 (edited) As a matter of interest, conventional geologists are not insensitive to other mechanical ideas. Indeed these days they like to try them out practically in models. Here are a couple of extracts from Twiss and Moores. The first shows mountain building as a result of tension. The second shows mountain building as a result of upwelling. I think the experimenter's ingenuity is to be commended. While you are a way the final chapters of Twiss and Moores Structural Geology and Ramberg's Gravity, deformation and the earth's crust would be worth a punt. Edited February 18, 2015 by studiot
arc Posted March 8, 2015 Author Posted March 8, 2015 (edited) Interestingly, this is actually evidence against your hypothesis. Your hypothesis requires oceanic crust formation to stop and start. However, these studies clearly show that oceanic crust formation is constantly ongoing. Evidence against? Constantly ongoing? This model only needs the mantle to slowly move out and then slowly move back in again, as in a cycle. What did that paper say? "A 20-Myr record of creation of oceanic lithosphere at a segment of the central Mid-Atlantic-Ridge is exposed along an uplifted sliver of lithosphere. The degree of melting of the mantle that is upwelling below the ridge, estimated from the chemistry of the exposed mantle rocks, as well as crustal thickness inferred from gravity measurements, show oscillations of, 3–4 Myr superimposed on a longer-term steady increase with time. The time lag between oscillations of mantle melting and crustal thickness indicates that the solid mantle is upwelling at an average rate of ,25mmyr, but this appears to vary through time." Below is my opening post of this thread; I’m describing the original and very simple model that I had used in the beginning to differentiate the various modes of the cycle. “So I started with a simple model, just a divergent plate boundary, a plate and a convergent boundary (trench). The cycle begins with a small thermal increase in the molten iron core from increased current due to induction from the strengthening of the Sun's magnetic field. As the molten core presses out from thermal expansion it expands the mantle ever so slightly which opens the divergent plate boundaries in the currently observed manner, filling with magma as they expand. After several million years of this solar increase induced cycle the Sun's magnetic field lowers and the Earth's field generator's core begins a cooler period of operation. As the core and mantle slowly recede the crust is put into compression against the newest divergent boundary deposits which leverages the crust towards the trench as the crust follows the mantle as it recedes from the cooling core. This is when the subduction takes place. The compression bleeds into the trenches until the next heat cycle increase.” sev·er·al ˈsev(ə)rəl/ determiner & pronoun 1. More than two but not many. It appears I predicted the duration of the cycle correctly. It is clear from that paper that the mantle moves out and then back in a cycle of several million years. It moves out far enough that its solid mantle material was left imbedded in the crustal record. “The time lag between oscillations of mantle melting and crustal thickness indicates that the solid mantle is upwelling at an average rate of ,25mmyr, but this appears to vary through time." I have already stated many times that this model uses the mantle’s outward movement to open all of the divergent boundaries to magma intrusion simultaneously. This periodic boundary infill material is what will later produce the increase of gravitational potential energy in the crust that drives subduction. And in the case of the Atlantic MOR this material will produce the force needed to drive the opposing continents apart as the mantle periodically subsides, and even more important, the energy to drive N. America over the Farallon plate. This will of course result in the Atlantic boundary being loaded periodically with much higher levels of compression than any of the other mid ocean ridge sections, because as I've already said the others have convergent boundaries that will process the compression while the Atlantic has no such stress relieving mechanisms, so the Atlantic MOR will be required to store this compressive energy long term as raised mass. And when there is a large differential between the quantity of divergent boundary material and the degree of mantle subsidence, as is the case with the Pleo-Pleistocene, there would be a tremendous amount of compression in the crust that would produce energies beyond what any convergent boundary could process. The Himalayas, the Andes and all other convergent and divergent boundaries are where this energy became stored. So we know that the mantle moves out and then back in because it has “oscillations”. I have posted repeatedly in this thread that the Pleo-Pleistocene mountain building period occurred simultaneously around the globe, the Himalayas, the Andes, the Coast Range and many others all occurred during the same geologic time period. These are simultaneous global events that require a simultaneous global solution to their causation. Would anyone argue that the crust would not be put into a compressive load state by these “oscillations”. That the entire crust would not be simultaneously leveraged against the most recent divergent boundary infill when the mantle moves down, causing the crust to slowly accumulate compression as the mantle recedes. “Interestingly, this is actually evidence against your hypothesis. Your hypothesis requires oceanic crust formation to stop and start. However, these studies clearly show that oceanic crust formation is constantly ongoing.“ Yes, it must stop and start. That is how the Earth’s surface acquired its current arrangement. Where can you see evidence of the “oscillation” process working within the time scale of the 3-4 Myr that was stated in the previous paper? The Yellowstone Hotspot’s intermittent progress eastward across the N.W. U.S. displays the pause that allows the caldera to form. This stationary period coincides to when the mantle is incrementally displacing outward as magma is filling the slowly opening divergent boundaries around the world. This new ridge material will in turn provide the leverage to produce the westward advancement of the N. American plate that simulates the Yellowstone hotspot’s movement east during the mantle’s subsequent return towards the core. The timing matches the article’s estimates; “oscillations of, 3–4 Myr superimposed on a longer-term steady increase with time. The time lag between oscillations of mantle melting and crustal thickness indicates that the solid mantle is upwelling at an average rate of ,25mmyr, but this appears to vary through time." Image provided by Kelvin Case at English Wikipedia, who has no connection to this author or this work. As you can see the fit is remarkable, this model matches not only the overall timing but the duration of the cycle segments of pause and then movement to the next hot spot location. Add to this the model's ability to furnish the energy to move the continental mass over the remains of the Farallon and the hot spot complex itself, makes this a very accurate prediction of observation. The current explanation for the Hawaiian-Emperor Sea Mount Chain is that they are the result of a hot mantle plume from the core/mantle boundary or are the result of a lithospheric extension that allows the passive rising of melt from a more shallow depth. The continuous plate movement of the standard model puts the responsibility of this island chain's periodicity of individual island building on a continually moving ocean plate squarely on the magma source and the requirement that it must have the unique ability to produce the magma in pulses so as to build islands separated by time and distance. The fact that the standard model does not offer a satisfactory means to move the plates in the first place only compounds the model’s problems regarding this phenomenon. The standard model appears to be a rather incomplete and complicated explanation that requires a tenuous expectation of the source’s ability to maintain such consistency over what likely extends beyond the farthest currently observed position of this system, considering the oldest seamount dates to where the chain is now being consumed into the Kuril–Kamchatka Trench 5,800 kilometers from the source’s current location suggests it is much older still. http://en.wikipedia.org/wiki/Hawaiian%E2%80%93Emperor_seamount_chain The oldest age for the Emperor Seamounts is 81 million years, and comes from Detroit Seamount. However, Meiji Guyot, located to the north of Detroit Seamount, is likely somewhat older. "Hawaii hotspot" by National Geophysical Data Center/USGS You have not fully appreciated the implications of the regular increase in age of the ocean floor rocks from as distance increases both east and west of the ridgeline. If, as you contend, the ridge is the result of pre-existing being thrust up under pressure from both sides (you cannot have compression from one side only) then, by definition of pre-existing, the ridge would be older rock. However some of the ridge rock is so young as to be dated 0 Y. If, you prefer to contend that compression led to the original upwellings then that upwelling cannot have been the present day ridge material because even the space it now occupies did not exist 200 MY BP, let alone the material to occupy it. Bold mine. Studiot , my argument is directed to the energy that the Atlantic MOR must process during times when the mantle subsides and the crust is compressed. Not the origin of the Atlantic MOR or its more distant history. My argument is directed at and in contradiction with the standard model over the extraordinary elevation of the Atlantic MOR and the reasons for it. I am not contending; "the ridge is the result of pre-existing being thrust up" as you state above. I think maybe you had misunderstood my example and my intention in regards to my posting of the Flat Iron mountain range that is located in a continental interior. They are the result of levels of compression that rival the Pleo-Pleistocene period. Levels so extraordinary they could buckle and stack continental sections at high degrees of angle. http://en.wikipedia.org/wiki/Rocky_Mountains "Immediately after the Laramide orogeny, the Rockies were like Tibet: a high plateau, probably 6,000 metres (20,000 ft) above sea level. In the last 60 million years, erosion stripped away the high rocks, revealing the ancestral rocks beneath, and forming the current landscape of the Rockies." These mountain ranges located on continental interiors are by the standard model unexplained due to the energy levels required, levels similar to the Pleo-Pleistocene. The Atlantic boundary is not special and cannot be excused from participating in the tribulations that the other boundaries must endure. The Pleo-Pleistocene was a global event and has left its mark as raised mass around the globe. The Himalayas, Andes and other examples show what this period has imposed on the planet’s crust within this recent past and includes by no exception the Atlantic MOR. Due to the adjacent plates lack of convergent boundaries to redirect these extreme energies the shape and height of the Atlantic MOR must reflect the events of that period. ...symmetry can develop on many levels; hint, hint, hint. Firstly, your “proto-basin with the divergent boundary at its center” is more analogous to a caldera, rather than to a basin …especially for the sort of geologic-scale basins you frequently mention, which don’t form this way. A cross section of the mid-Atlantic Ridge (MAR) looks like a cross section of the typical volcano, with its caldera appearing as a low basin in the center, surrounded by steep jagged peaks that then slope away to each side. But secondly, your “proto-basin with the divergent boundary at its center” should be located at the “0” km point, on the x axis of “distance, km,” shouldn’t it? The “distance, km” is the distance away from the spreading center, or the “proto-basin with the divergent boundary at its center,” which the previous pictures of the MAR zoomed in on, isn’t it? I’d expect that blue valley, in the center of those earlier pictures, is (half) shown at the far left of these two cross-sections, both marked at between 3100 and 3400 meters below sea level. I like the way you zoomed in on the MAR, but [unless I'm mistaken about how you "tried to center on the ridge every time] ...when you transitioned to cross sections, I think your graphics got shifted east, relative to the center of the MAR. The “basin” and the peaks that you’re looking at are normal topography, for each side of a rift valley, as shown widely on the internet, istm: …just add some sediment onto the low spots, on one side of the MAR, and it would look more like those cross sections you have. Do the points about buoyancy and subsidence, in billiard’s post #393 & 396, not make sense to you; or perhaps it is just that those points don’t make sense in your model? === ...and thirdly: Certainly, “more than 4 times wider” is true, but I wonder if you see why it must be over 5 times wider; or indeed 7.5 times wider? ~ Essay, could you possibly explain where the spreading center is in that image? The real boundary is diverging in opposite directions. That image should show where the 25 mm of magma a year is being injected in between the diverging plate sections. Are you proposing that the center section shown in that image will eventually rise up and split in half? What I do see in that image is where magma would be injected on either side of that center section when the mantle displaces outward, sort of a 12.5 mm of magma on each side per year. That center section would then continue to grow in width. "I think your graphics got shifted east, relative to the center of the MAR." I was very careful when I did those cross sections and the site is very easy to operate. I am quite positive they are on the ridge center. Edited March 8, 2015 by arc
studiot Posted March 8, 2015 Posted March 8, 2015 http://www.colorado.edu/ASEN/asen6090/SolidTides.ppt arc Studiot , my argument is directed to the energy that the Atlantic MOR must process during times when the mantle subsides and the crust is compressed. Not the origin of the Atlantic MOR or its more distant history. My argument is directed at and in contradiction with the standard model over the extraordinary elevation of the Atlantic MOR and the reasons for it. I'm confused by this. Are you now saying the oceanic ridges were not created, in stages, by upwelling magmatic material? What you you mean by the extraordinary elevation? What is extraordinary about it? And what about my question concerning the pattern of horizontal distribution of rock age away from the centre of the ridge? Once again you have put a lot of effort into unconnected pretty pictures instead of responding to statements by others in this conversation. So how is it a conversation? I posted some examples of useful experiments I thought you might like to do for yourself, but you have not even acknowledged that post. Finally here is another question for you to ignore. The surface of the Earth is constantly going up and down by a measurable few inches. Have you heard of Earth Tides? Here are some measurements. http://www.colorado.edu/ASEN/asen6090/SolidTides.ppt I am rather disappointed. 1
billiards Posted March 9, 2015 Posted March 9, 2015 It appears I predicted the duration of the cycle correctly. If you allow us to remember the Japanese earthquakes. You were then predicting cycles on timescales of human history (thousands to tens of thousands of years). Now you've changed your mind -- it' million of years. Are we forgetting all that Japanese earthquake stuff now? It is clear from that paper that the mantle moves out and then back in a cycle of several million years. It moves out far enough that its solid mantle material was left imbedded in the crustal record. Aside tip on scientific communication: Arc it is not clear "from that paper". It would be better to say something along the lines: "it is clear that X is true based on the evidence Y (reference to paper)". Anyway, my understanding is that the mantle is constantly supplying melt to produce oceanic crust, but the rate at which it provides melt is fluctuating. It is entirely not clear that the mantle is moving "out and then back in a cycle of several million years" at all, at least not to me! That's your spin on it! Vitally, there is no mention of stopping and starting which you agree your model requires ... Yes, it must stop and start. That is how the Earth’s surface acquired its current arrangement. This will of course result in the Atlantic boundary being loaded periodically with much higher levels of compression than any of the other mid ocean ridge sections, because as I've already said the others have convergent boundaries that will process the compression while the Atlantic has no such stress relieving mechanisms, so the Atlantic MOR will be required to store this compressive energy long term as raised mass. Then where are all the compressive faults? (another question repeatedly ignored!) As you can see the fit is remarkable, this model matches not only the overall timing but the duration of the cycle segments of pause and then movement to the next hot spot location. Add to this the model's ability to furnish the energy to move the continental mass over the remains of the Farallon and the hot spot complex itself, makes this a very accurate prediction of observation. This is ridiculous. Your model is global. How on Earth does it predict local "hotspot" volcanism?
arc Posted November 9, 2015 Author Posted November 9, 2015 (edited) I'm confused by this. Are you now saying the oceanic ridges were not created, in stages, by upwelling magmatic material? What you you mean by the extraordinary elevation? What is extraordinary about it? And what about my question concerning the pattern of horizontal distribution of rock age away from the centre of the ridge? Once again you have put a lot of effort into unconnected pretty pictures instead of responding to statements by others in this conversation. So how is it a conversation? I posted some examples of useful experiments I thought you might like to do for yourself, but you have not even acknowledged that post. Finally here is another question for you to ignore. The surface of the Earth is constantly going up and down by a measurable few inches. Have you heard of Earth Tides? Here are some measurements. http://www.colorado.edu/ASEN/asen6090/SolidTides.ppt I am rather disappointed. studiot, I'm confused also. I'm avoiding falling into the hole you have dug for me to fall into. It reminds me of that gotcha question a reporter asked the politician - "Do you still beat your wife?" How can I convince you that I am referring to a specific period of time several million years ago when mountain ranges around the world suddenly rose up. These mountains are on continental to continental boundaries (Himalayas), oceanic to continental boundaries (Andes), and as I'm claiming here, oceanic to oceanic boundaries (Mid Atlantic Ridge) I can show the Atlantic's exceptional size (and yes it is exceptional compared to all other MORs) is the result of the same forces as those other mountain ranges mentioned, and others not mentioned but date to the same time period. So this is about globally dispersed boundary deformation that took place around 2-4 million years ago. The reasons why some boundaries produced mountains and others didn't will hopefully be explained here. So according to this model the Atlantic oceanic basin has not deviated from what you have always assumed it was from its creation to the present. It's just that I believe several million years ago the earth crust became loaded with an unusual level of GPE and it overwhelmed certain boundaries, one of these was the Atlantic's boundary, its unusual height and width the result of this sudden mountain building during Plio-Pleistocene. I am not trying to ignore your questions as much as I am trying with all effort to keep this conversation focused on the idea that Dr. Ollier presented; Mountain uplift and the Neotectonic Period I have posted the excerpt of this by Dr. Ollier repeatedly, it has been pretty much ignored with the exception of; http://www.scienceforums.net/topic/73730-plate-tectonic-mechanism/page-20#entry851176 So I’m again attempting show how these remarkable observations of the Himalayas by Gansser (1991), Wu et al. (2001), Zheng et al. (2000) and many others should on their own, be of interest to everyone who visits or participates on this thread. Do these observations somehow challenge ones preconceptions of how this planet operates? That the tallest mountains on the planet today were not much higher than what the Tibetan Plateau's Kunlun Pass area's elevation was several million years ago. “According to Wu et al. (2001) from the Pliocene to the Early Quaternary (5-1.1 Million years) the Kunlun Pass area of the Tibetan Plateau was no more than 1500 m high and was warm and humid.” The time frame I’m discussing here begins at that time of the Pliocene and extends into the Pleistocene where most this mountain uplift was largely completed. This was a massive expenditure of energy in an incredibly short period of time. And it occurred in both hemispheres and multiple continents all at the same time. Does anyone find this more than a little challenging for the standard model to explain? OK, back to square one. Let’s imagine that the new divergent boundary infill that is currently being placed in all the world’s MORs is due to the Earth’s crust is being simultaneously moved outward by the mantle oscillations as described by; http://www.researchgate.net/publication/10736864_Bonatti_E._et_al._Mantle_thermal_pulses_below_the_Mid-Atlantic_Ridge_and_temporal_variations_in_the_formation_of_oceanic_lithosphere._Nature_423_499-505 "A 20-Myr record of creation of oceanic lithosphere at a segment of the central Mid-Atlantic-Ridge is exposed along an uplifted sliver of lithosphere. The degree of melting of the mantle that is upwelling below the ridge, estimated from the chemistry of the exposed mantle rocks, as well as crustal thickness inferred from gravity measurements, show oscillations of ,3–4 Myr superimposed on a longer-term steady increase with time. The time lag between oscillations of mantle melting and crustal thickness indicates that the solid mantle is upwelling at an average rate of ,25mmyr, but this appears to vary through time." The three important clues that stand out to me and can be correlated to my idea are; 1.-A 20-Myr record of creation of oceanic lithosphere 2.-oscillations of ,3–4 Myr 3.-longer-term steady increase with time 4.-the solid mantle is upwelling at an average rate of ,25mmyr, but this appears to vary through time." Now let’s look at a simple dynamic model of the earth’s crust that resembles what the convergent and divergent boundaries looked like prior to that period described by Dr. Ollier below; ANNALS OF GEOPHYSICS, SUPPLEMENT TO VOL. 49, N. 1, 2006 Mountain uplift and the Neotectonic Period CLIFF D. OLLIER School of Earth and Geographical Sciences, University of Western Australia, Perth, Australia 9.2. EXAMPLES 9.2.1. Tibet, Himalayas, Kunlun Mountains (As an example, consider the timing of uplift in Tibet and its bordering mountains. Gansser (1991) wrote: «... we must realize that the morphogenic phase is not only restricted to the Himalayas but involves the whole Tibetan block. This surprising fact shows that an area of 2500000 km2 has been uplifted 3000-4000 m during Pleistocene time and that this uplift is still going on.» In places the uplift rate is 4.5 mm/yr (five times the maximum in the European Alps). According to Wu et al. (2001) from the Pliocene to the Early Quaternary (5-1.1 Million years) the Kunlun Pass area of the Tibetan Plateau was no more than 1500 m high and was warm and humid. They write: «The extreme geomorphic changes in the Kunlun Pass area reflect an abrupt uplift of the Tibet Plateau during the Early and Middle Pleistocene. The Kunlun-Yellow River tectonic movement occurred 1.1-0.6 Million years.» Zheng et al. (2000) concluded from sediments at the foot of the Kunlun Mountains that uplift began around 4.5 Million years.) And consider this also; http://www.rochester...n-in-the-andes/ “This study provides increasing evidence that the plateau formed through periodic rapid pulses, not through a continuous, gradual uplift of the surface, as was traditionally thought,” said Garzione. “In geologic terms, rapid means rising one kilometer or more over several millions of years, which is very impressive.” “What we are learning is that the Altiplano plateau formed by pulses of rapid surface uplift over several million years, separated by long periods (several tens of million years) of stable elevations,” said Garzione. http://www.rochester.edu/news/show.php?id=3167 “Tectonic Theory May Need Revision in Light of New Study in Science” “Mountains may experience a "growth spurt" that can double their heights in as little as two to four million years—several times faster than the prevailing tectonic theory suggests.” “By studying sedimentary basins in the high Andes Mountains, the team could determine when and at what altitude these ancient sediments were deposited. That record of altitude changes shows that the Andes Mountains rose slowly for tens of millions of years, but then suddenly lifted much faster between 10 and 6 million years ago.” This mountain building in the Himalayas, Andes and other locations started with raising large areas of much lower land simultaneously around the world in very short periods of time. If we could imagine that the crust could supply its own energy to do this by utilizing the GPE it attains when the mantle changes from when 4.-“the solid mantle is upwelling at an average rate of ,25mmyr” to when it moves down once again. The GPE in the crust would then increase because the divergent boundary infill in all boundaries from the last “upwelling” phase of the cycle would need to push the plates towards a convergent trench to equalize the growing compressive energy that the most recent infill is now being subjected to and is passing on to all the planet’s plates. We should then be able to look at the boundaries around the world, both convergent and divergent, and see evidence of their interaction with this last episode of higher GPE that occurred during the Plio-Pleistocene mountain building era. An important point to remember is; if the crust that is adjacent to the boundary (convergent or divergent) is unable to move towards a lower energy state that is at a level of resistance low enough to process the mantle’s rate of subsidence then the boundary, whether it is convergent or divergent, will be subjected to higher compressive energies. This image above represents a divergent boundary similar to the Pacific’s. If we were to imagine the mantle under it had begun moving downward the two continents would begin to move towards each other, and because the world is a sphere they would move towards all the other continents also. The opposing oceanic plates in the image would begin to compress their divergent boundary. But the compression could only reach to the level that the subducting crust encounters at the opposing convergent trenches. The trenches behave as compression relieving mechanisms and limit the amount of compression the divergent boundary can be subjected to. This illustration above represents a combined continental/oceanic spreading center arrangement similar to that of the Atlantic’s. The oceanic crusts are attached to their parental continents as they have been since they first divided. As the two continents move towards each other the convergent boundary is loaded with compression, the oceanic plates respond to this in the only way they can, by pushing back. In this scenario it would be reasonable to expect the Atlantic boundary, in not having the compression relieving mechanisms of convergent boundary trenches, would experience higher levels of compression then the Pacific would. When there is 1.-“A 20-Myr record of creation of oceanic lithosphere” with 2.-“oscillations of ,3–4 Myr”, during which they have a 3.-“longer-term steady increase with time” during which 4.-“the solid mantle is upwelling”; the following subsidence period would have a larger portion of GPE in the crust. A “steady increase with time” over a period of 20 million years would leave a gradually building inventory of surplus divergent boundary material to be dealt with. When the “20 Myr increase with time” period finally comes to an end and a longer than normal period of subsiding mantle is waiting there for it, the Plio-Pleistocene mountain building period that occurred around the planet would be the result. These illustrations below represent a combined continental spreading center arrangement similar to that of the Atlantic’s. The oceanic crusts are attached to their parental continents as they have been since they first divided. As the mantle moves downward the oceanic crusts are loaded with proportional amounts of GPE. The only compression relieving mechanism available in this situation is the continents will need to overcome the resistance that they have to moving to a lower energy state by sliding towards the nearest convergent boundary available. In the Atlantic’s situation this would undoubtedly be greater then what the Pacific’s oceanic plates are subjected to. For example: the energy required to move N. America over the subducted Farallon and then Pacific oceanic plates would be much greater than with what the Pacific expends just subducting into an adjacent convergent trench. In these images above the subsiding mantle during a typical non mountain building subsidence period loads the crust with increasing levels of GPE, eventually this will dissipate as the continents shift to a lower energy state (bottom image) What would we expect to see during those mountain building periods? The GPE is greater during these periods and would compress the Atlantic oceanic plates to greater levels. It would actually raise the oceanic plate’s elevation, crushing the boundary substantially over time. The boundaries newest infill would be the thinnest and softest material. The greater levels of GPE would crush these weakest areas of the crust, eventually transforming this boundary into the largest oceanic mountain range on the planet. What would you say if I was to furnish evidence that the Atlantic divergent boundary was periodically loaded with levels of GPE derived compression so large that the divergent boundary came to the ocean’s surface? And further, that one of these extreme compressive periods occurred during the Plio-Pleistocene mountain building period when the Himalayas and Andes grew at their greatest rates. http://www.researchgate.net/publication/221939638_The_Vema_Transverse_Ridge_(Central_Atlantic) “Multibeam morphobathymetric coverage of the entire Vema Transverse ridge shows it is an elongated (300 km), narrow (<30 km at the base) relief that constitutes a topographic anomaly rising up to 4 km above the predicted thermal contraction level. Morphology and lithology suggest that the Vema Transverse ridge is an uplifted sliver of oceanic lithosphere. Topographic and lithological asymmetries indicate that the transverse ridge was formed by flexure of a lithospheric sliver, uncoupled on its northern side by the transform fault. The transverse ridge can be subdivided in segments bound by topographic discontinuities that are probably fault-controlled, suggesting some differential uplift and/or tilting of the different segments. Two of the segments are capped by shallow water carbonate platforms, that formed about 3–4 m.y. ago, at which time the crust of the transverse ridge was close to sea level. Sampling by submersible and dredging indicates that a relatively undisturbed section of oceanic lithosphere is exposed on the northern slope of the transverse ridge. Preliminary studies of mantle-derived ultramafic rocks from this section suggest temporal variations in mantle composition”. . . . . . “Studies of depth-sensitive fossils and diagenetic textures in the dredged lime-stones have provided the rough outlines of a paleodepth versus age history for the transverse ridge crest. The summit of the transverse ridge was at or above sea level up to about 3 m.y. age, and has since subsided to its present depth (Bonatti et al., 1983)”. . . . . . . “We carried out one dredge on the limestone cap (dredge EW9305-1), recovering a large block of coral resting on a platform of coarse cemented biogeneous calcareous sand, plus smaller pieces of heterogeneous cemented biogeneous limestones, and half a dozen rounded pebbles resembling beach pebbles. . . . . .These new samples are compatible with the previous interpretation that the limestone cap was formed near sea level and subsided to its present location”. . . . . “The uniformity of the transverse ridge profile between 43400W and 42300W, in particular the along-strike persistence of the characteristic stair step morphology on the northern flank, lead us to suggest that an intact block of oceanic lower crust and upper mantle, more than 100 km long, was uplifted without major internal disruption.” The problem for you is I do mind. I mind very much when I see someone get it so badly wrong. You still haven't even acknowledged the two very crucial points I have made: • The Parsons and Sclater (1977) thermal model to explain sea floor bathymetry (this is why you get the "mountain range" at the mid-Atlantic ridge) • The complete lack of compressional faulting on the ocean floor (i.e. no evidence for past compression -- proving your model is wrong) Those above points are real science ... PLEASE address them ... Your tactics are to shift the goal posts ... The standard model explains all the features you have mentioned easily (as I have already posted): • The valley is an extensional feature caused by the two plates drifting apart. It' a simple consequence of structural geology. You also have the same feature in the Pacific spreading ridges, the East African spreading ridge, etc. etc.. in fact generally you get basins wherever you get extensional tectonics. Now please explain why there are no compressional faults on the ocean floor, according to your model. The standard model or The Parsons and Sclater (1977) thermal model have no reasonable explanation for this incredible fact that this section was near the surface when the Andes and Himalayas were rising. This would then indicate that the The standard model or The Parsons and Sclater (1977) thermal model are not making accurate prediction of observations. The study I posted above suggests that the entire Mid Atlantic Ridge was elevated to some greater degree for several million years concurrent to when the Andes and Himalayas were rising. This model would suggest it was dependent on the available GPE derived compression present in the crust during this time. Billiards, would you take your “real science” and ... “PLEASE address” this. This next one has several observations to support this hypothesis. http://www.researchgate.net/profile/Luca_Gasperini/publication/221939595_Lower_Cretaceous_to_Eocene_sedimentary_transverse_ridge_at_the_Romanche_Fracture_Zone_and_the_opening_of_the_equatorial_Atlantic/links/02bfe50e54bab7655e000000.pdf “The Romanche transform offsets the Mid Atlantic Ridge by about 900 km and is the largest of a set of major equatorial Atlantic fracture zones. Assuming for the crust adjacent to the transform an average spreading rate of 1.75 cm/yr (Cande et al., 1988) and a constant ridge/ transform geometry, the age offset of the Romanche transform is roughly 50 million years. A transform-parallel transverse ridge, running adjacent to the northern side of the fracture zone is particularly prominent for a stretch of several hundred kilometers centered opposite to the eastern ridge/ transform intersection (RTI), where the topographic anomaly reaches 4 km above the predicted thermal contraction level (Bonatti et al.,1994). Seismic reflection data and extensive rock sampling indicate that the western portion of the transverse ridge . . . . consists of slivers of uplifted oceanic crust and upper mantle (Bonatti et al.,1994). The summit of the transverse ridge is capped in this area by Miocene shallow water limestones that reached above sea level about 20 ma, and then subsided at a rate faster than that of “normal” lithospheric cooling. (Gasperini et al.,1997a)”. . . . . Under this “Miocene shallow water limestones” is a layer of deep-water sediments as old as 140 Ma that are on top of oceanic crust estimated to be 50 million years old. . . . . .”The presence of such a thick sedimentary sequence, including deep-water sediments as old as 140 Ma, less than 150 km from the RTI, does not fit a normal sea-floor spreading scenario and opening of the equatorial Atlantic.” Post 415 Billards said: "Interestingly, this is actually evidence against your hypothesis. Your hypothesis requires oceanic crust formation to stop and start. However, these studies clearly show that oceanic crust formation is constantly ongoing." Bold mine. You may want to reconsider that post in light of the 140 Ma sediments on top of what the standard model assumes to be 50 MY crust. If one would consider that the subduction in this model takes longer to process an equal amount of divergent boundary infill, then what is an anomaly for the standard model is easily explained by this model. This is the second post that I made on this thread. In my model this would indicate that the subduction lags behind the expansion portion of the cycle. It takes longer for the plates to melt into the asthenosphere than it does to create the infill that leverages the plate into the trench. So the answer to why is there some subduction happening now?, would be because not all of the plate compression (probably the largest ones) has bled out into the trenches before this current expansion cycle started. The outer core thermal cycle is variable throughout its cycle, even from one maximum to the next in both timing and duration. Now let's say we have a extra long thermal expansion cycle and the divergent plate boundaries build up a very large infill, one of those that only happens every 20 or 30 million years. When the outer core begins to cool and initiates the plates subduction the trenches will be, like before, slower to receive the plate material than the mantles withdraw. Just to point it out, the time span between the Vema and Romanche ridge’s “carbonate caps” is 20 million years. The divergent boundary infill material is extruded into the divergent boundary openings as the mantle is displacing outward, tearing the crust/mantle boundary surface area and releasing the thermal energy that produces melting of the C/M boundary area materials. Subduction will take place continuously because there is enough GPE in the crust to overcome the resistance of the convergent trenches. When the mantle begins contracting the divergent boundaries stop spreading and begin compressing. The magma in the crust/mantle boundary area that is created during the mantle’s displacement is now cooling and reforming into mantle surface material. The subducting crust will find the surface and mantle interior tightening its grip as it attempts to further penetrate. This resistance decreases subduction rates and has helped maintained the crust’s current GPE that is currently still pushing the Himalayas and Andes still higher. The current outward displacement of the mantle that is seen in all of the divergent boundaries presently, is with the subduction taking place around the world, slowly removing the crust’s inventory of GPE. The much slower but always occurring subduction has been able to increase since the mantle has begun to displace outward once again. The mantle’s outer boundary has expanded and melted from the release of strain energy allowing the plate to move more easily into the now much “softer” mantle material. Considering that the sea floor age estimates at the Romanche Fracture Zone look to be off by over by 90 million years this model’s increase of time vs sea floor spreading metrics by possibly more than double and decrease of subduction rates due to when the mantle is cooling during those periods of no seafloor production, the 140 million year age estimate at the Romanche Fracture Zone is quite possible with this model. If you allow us to remember the Japanese earthquakes. You were then predicting cycles on timescales of human history (thousands to tens of thousands of years). Now you've changed your mind -- it' million of years. Are we forgetting all that Japanese earthquake stuff now? Aside tip on scientific communication: Arc it is not clear "from that paper". It would be better to say something along the lines: "it is clear that X is true based on the evidence Y (reference to paper)". Anyway, my understanding is that the mantle is constantly supplying melt to produce oceanic crust, but the rate at which it provides melt is fluctuating. It is entirely not clear that the mantle is moving "out and then back in a cycle of several million years" at all, at least not to me! That's your spin on it! Vitally, there is no mention of stopping and starting which you agree your model requires ... Then where are all the compressive faults? (another question repeatedly ignored!) This is ridiculous. Your model is global. How on Earth does it predict local "hotspot" volcanism? Again you are either simply wrong or purposely trying to again misrepresent what this model has presented. The earthquakes simply correlated to changes in solar magnetic flux. The 14C proxy data correlate the Sun’s most pronounce changes in solar magnetic energy to the timing of the Japanese earthquake records. And by this it shows how the liquid iron of the Earth’s field generator inductively responds to the Sun’s magnetic flux. When the molten iron expands or contracts the mantle will magnify this very minute change in the outer core’s thermal content to larger crust/mantle boundary movement. The Pacific plate will magnify this movement even further and produce the recorded seismic events. The earthquakes occur at precise points of large increases or decreases of solar magnetic content and timing, a very simple idea. Could it be that it being so simple is the reason that no one had thought of it before? I do recall someone promoting the idea that we should believe that there were other unrecorded Japanese earthquakes in the past that would then skew my evidence. I then showed by the latest research that they probably did not exist. And then nobody wanted to discuss it any further until now. http://www.scienceforums.net/topic/73730-plate-tectonic-mechanism/page-18#entry815114 As a side note; I believe the Vema and Romanche ridges, located in the central Atlantic and being so close to each other, is not random or a coincidence. If the mantle was to move down ever so slightly and move all the plates towards each other simultaneously, the four opposing continents of the Atlantic would compress in the manner seen below; But an area of the Atlantic basin that is narrower (the equatorial being the only one) would be required to process a similar quantity of lateral continental movement that a wider basin area such as the North Atlantic would need to. The narrower section would process this disproportionate and higher continental-movement-to-basin-width-ratio by either compressing the divergent boundary more or raising it higher than the adjacent and wider basin areas to the north and the south were raised. This prediction of observation appears, with the others, to hold true. "This is ridiculous. Your model is global. How on Earth does it predict local "hotspot" volcanism?" No - It just accurately predicts its movement as N. America moves over it. Edited November 9, 2015 by arc
billiards Posted November 9, 2015 Posted November 9, 2015 Welcome back arc, nice to see that after the long break you are still adhering more strongly than ever to your beloved paradigm of planetary sciences! Let's see if this time you can break through the most rigorous barriers we can assemble for you and shatter our perception of reality. One small thing I think you forgot to address. Where are the compressive faults?
studiot Posted November 9, 2015 Posted November 9, 2015 As the mantle moves downward the oceanic crusts are loaded with proportional amounts of GPE. The only compression relieving mechanism available in this situation is the continents will need to overcome the resistance that they have to moving to a lower energy state by sliding towards the nearest convergent boundary available. In the Atlantic’s situation this would undoubtedly be greater then what the Pacific’s oceanic plates are subjected to. For example: the energy required to move N. America over the subducted Farallon and then Pacific oceanic plates would be much greater than with what the Pacific expends just subducting into an adjacent convergent trench Would you like to explain this. It makes no sense to me. Nor does showing pictorial sequences of allegedly convergent or divergent boundaries all the same distance apart. I would suggest you need to conduct some old fashioned geological investigation before offering some of the above statements of geological history. You should check that the actual rocks found in the field conform to your theory. Are they of the correct Age? Are they of the correct type - sedimentary or igneous? What is the orientation of their bedding? Are they the right way up or is there an inversion unconformity? For instance a recent poster failed to do this with another theory of the Himalaya http://www.scienceforums.net/topic/91603-evolution-of-himalayas-and-tibet-and-the-great-volcano/ And failed to realise that the region comprises two distinct blocks one sedimentary and one igneous. Please make sure you do not fall into the same trap. Incidentally no one here is trying to cleverly trap you. studiot, I'm confused also. I'm avoiding falling into the hole you have dug for me to fall into. It reminds me of that gotcha question a reporter asked the politician - "Do you still beat your wife?" But we will rigorously test your statements for logical consistency, both with known observed facts like the known geological maps and sections and other measurements, and internally with themselves. Nice to see you back.
billiards Posted November 11, 2015 Posted November 11, 2015 (edited) Arc, In the argument about fast mountain building and episodic growth spurts: 1) You show some problems with the standard model. Great, very interesting! 2) You add some kind of alternative explanation (in the form of cartoons). OK good you're thinking at least! Now just add the maths! 3) You add some evidence -- midocean ridges bulge upwards. Here are the problems: • The evidence does not support your theory because your model is nothing more than cartoons -- you really need those numbers! • One obvious consequence of your model is that there would need to be compressive faults at the mid ocean ridges to accomodate the crustal shortening. There aren't any observed in nature. BOOM your theory is wrong. (truth hurts sometimes) • There is already a perfectly good *quantitative* description of the mid ocean ridge bulge (Parsons and Sclater). This latter point relates to your second argument about the height of transform ridges. Here you: 1) You show that transform ridges bulge upwards and this is not explained by the Parsons and Sclater model. Great, how interesting! 2) You ramble on for a while without making a coherent point. Presumably here you mean to destroy the standard model again and thereby free your path to our hearts and minds. However, just because the Parson and Sclater model does not explain EVERYTHING does not mean that it explains NOTHING. To me, the failure of the Parsons and Sclater model at the these locations reveals that the underlying physics used in that model does not apply in these situations. Parson and Sclater model is a thermal model of topography, and therefore the bulges at tranform faults are not thermal features. Besides, non of this helps you to escape the fact that there are still no compressive faults at the mid-ocean ridges. And that for me is the killer blow to your theory. You could disprove Parsons and Sclater all day long and it wouldn't make the darndest difference. Edited November 11, 2015 by billiards
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