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I think that the ocean in fact does not get bigger because of plate tectonics. If the magma spreads the plates apart and creates more oceanic crust, then the oceanic plates will just go below other plates and the ocean will get new crust and lose old crust. I do think, however, that the land masses will get bigger from the rifts on the land and the land plates will go over all the oceanic crusted plates. User:65.74.253.34
The Earth can't get bigger due to subduction zones that destroy the older rock, so you are indeed correct that the ocean floor does not get bigger. It's almost like two steps forward and two steps back.
I agree with a guy above me. Vinaq 19:57, 6 March 2007 (UTC)Vinaq
Yes, it maybe true on the part that it may be a cycle so the earth would not get bigger, however, it doesn't really answer the question given by Emilyjane. If that is so therefore in the future the ice that has been melted would not contribute to the volume of water in the earth? it is 70% water and only 30% of land mass, would that percentage increase? vahn_dinio 10:25, 15 May 2008
Is it just me, or is this hard to read? I think it needs cleanup, but I need approval before the stamp goes up. -Anonymous
I finished my geophysics degree almost 10 years ago but at that time we were taught that the driving mechanism was the weight of the subducting slab pulling the oceanic crust along. The magma coming up at the mid-ocean ridges is described as "passively upwelling". I am quite surprised that this article mentions there is still some debate over the mechanism of sea-sloor spreading. Is this really so? Can smoeone point to some recent papers on this matter? The arguments I heard 10 years ago seemed quite compelling but beyond old university notes I can't really give any sources. To me, the obvious problem with magma forcing itself out is why would this push the plates sideways? Would it not just pile up on the ocean floor, a la hot-spot island arc volcanoes? One would also need a driving force to push this magma up and none has yet been identified, to my knowledge. As an aside, I also recall how there was some theory that magma plumes in the Earth's mantle were caused when a down-going subducted slab hit the Earth's outer core. Again, this is only a tenuous theory and I can't back it up. Robruss24 ( talk) 16:47, 29 January 2009 (UTC)
The problem is that although the section is titled Search for a Mechanism and Debate, neither of these things is at all discussed; rather one mechanism is posited, unqualified as to importance, as the mechanism. As noted above, it was qualified somewhat with the "active margins" clause, but no context for active margins is given.
There does, in fact seem to be debate on the mechanisms; ridge push is not discussed, neither how it is thought to work, nor the reason it is not currently considered the greatest factor in the movement rates. It is, however, a factor and should be discussed, if at least in terms of the 'debate'. As I understand it, basal drag has traditionally been considered a considerable force, too. In fact, unless I understand it incorrectly, Hess considered this force to be what caused rifting in the first place because of the force that a laterally moving convection current exerts upon the crust. 124.171.62.71 ( talk) 08:58, 26 August 2014 (UTC)
This process (without a sea) appears not to occur on any other planet or moon in the solar system. [See section 9 of Plate tectonics]. Is that worth mentioning? -- Tediouspedant ( talk) 23:04, 6 March 2010 (UTC
There are no pictures of geysers on Europa. So it appears not. I've seen no evidence of plates on the moon. I've seen no evidence of plates on earth, only earthquakes - which could just as easily by tidal forces on land. Why is this a thing?
Earth expands... sea floor spreads... continents move further apart... continents flatten... intra-plate earthquakes... d'oh! It's sooo obvious but too hard to go back and admit plate tectonics is shite! — Preceding unsigned comment added by 202.162.74.172 ( talk) 06:45, 24 August 2011 (UTC)
In the lead we find this phrase:
It is not clear to from the text in the lead if convection is happening in the asthenosphere it self or in the mantle under it. For me it seems more likely that the astenosphere is the boundary layer between convecting mantle and rigid lithospheric mantle. That part of lead does cite a 1971 paper, I would suspect there are newer sources that are more clear and assertive on the subject.
— Lappspira ( talk) 00:15, 2 October 2016 (UTC)
Because this section deals largely with mid-ocean ridge depth profiles I suggest it be moved to the mid-ocean ridges article. BrucePL ( talk) 19:10, 29 March 2018 (UTC)
@ Dan Gluck: Good grief! Has it been over a year since we corresponded about this? I just did a bunch of edits on the MOR page and was reminded of the half-space chat we had. I'll set about copying the model to MOR with a link on SFS article to the model section on MOR. BrucePL ( talk) 16:46, 17 September 2019 (UTC)
This section is now on its own page Seafloor depth versus age. I will do some consolidating of this section and delete the math because it is now on its own page. Links on this page will direct reader to the details on the new page. BrucePL ( talk) 00:05, 31 January 2020 (UTC)
What does determine the direction and drift of lithosphere plates ? And what does give the force to move the plates and what is a reason that somewhere arise a knew Rift ? So what is the reason, that somewhere the lithosphere-plate is heating up ? I would say it's the Mantle Convection, but the german Wikipedia says, it's not that. it's the weight of the plates. I think that's not true.
Sorry for my english. — Preceding unsigned comment added by 2A02:1203:ECBD:A300:5D01:CC46:C2D6:57D2 ( talk) 07:37, 31 October 2018 (UTC)
I worked on this section adding the cooling plate model for seafloor depth (and crustal heat flow). I suggest that this topic be made its own page and creating short content on the Seafloor Spreading (and Mid-ocean ridge page) that directs a reader to the new page.
My thinking is that the derivation of the cooling mantle model is fairly advanced; it includes solving partial differential equations, not usually encountered in WP STEM pages.
The derivation is useful, however, as it includes fundamental principles of solving differential equations by setting boundary conditions and approximations.
Thoughts anyone? BrucePL ( talk) 19:45, 26 November 2019 (UTC)
The physical phenomena of convection includes any case where in one part you have hot matter that ascends, then cools down and goes down in another part. When it is not driven by the temperature difference it is called forced convection, but it is still convection. Anyway, as far as I understand, plate tectonics is in fact driven by temperature differences, so it is a regular convection and not forced - this is true whether it is driven by slab pull due to the margins being cold (after cooling down) or by ridge push due to hot material ascending from below, or due to mantle convection (with the latter option probably not true). Dan Gluck ( talk) 18:35, 25 September 2020 (UTC)
This article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||||||||||||
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I think that the ocean in fact does not get bigger because of plate tectonics. If the magma spreads the plates apart and creates more oceanic crust, then the oceanic plates will just go below other plates and the ocean will get new crust and lose old crust. I do think, however, that the land masses will get bigger from the rifts on the land and the land plates will go over all the oceanic crusted plates. User:65.74.253.34
The Earth can't get bigger due to subduction zones that destroy the older rock, so you are indeed correct that the ocean floor does not get bigger. It's almost like two steps forward and two steps back.
I agree with a guy above me. Vinaq 19:57, 6 March 2007 (UTC)Vinaq
Yes, it maybe true on the part that it may be a cycle so the earth would not get bigger, however, it doesn't really answer the question given by Emilyjane. If that is so therefore in the future the ice that has been melted would not contribute to the volume of water in the earth? it is 70% water and only 30% of land mass, would that percentage increase? vahn_dinio 10:25, 15 May 2008
Is it just me, or is this hard to read? I think it needs cleanup, but I need approval before the stamp goes up. -Anonymous
I finished my geophysics degree almost 10 years ago but at that time we were taught that the driving mechanism was the weight of the subducting slab pulling the oceanic crust along. The magma coming up at the mid-ocean ridges is described as "passively upwelling". I am quite surprised that this article mentions there is still some debate over the mechanism of sea-sloor spreading. Is this really so? Can smoeone point to some recent papers on this matter? The arguments I heard 10 years ago seemed quite compelling but beyond old university notes I can't really give any sources. To me, the obvious problem with magma forcing itself out is why would this push the plates sideways? Would it not just pile up on the ocean floor, a la hot-spot island arc volcanoes? One would also need a driving force to push this magma up and none has yet been identified, to my knowledge. As an aside, I also recall how there was some theory that magma plumes in the Earth's mantle were caused when a down-going subducted slab hit the Earth's outer core. Again, this is only a tenuous theory and I can't back it up. Robruss24 ( talk) 16:47, 29 January 2009 (UTC)
The problem is that although the section is titled Search for a Mechanism and Debate, neither of these things is at all discussed; rather one mechanism is posited, unqualified as to importance, as the mechanism. As noted above, it was qualified somewhat with the "active margins" clause, but no context for active margins is given.
There does, in fact seem to be debate on the mechanisms; ridge push is not discussed, neither how it is thought to work, nor the reason it is not currently considered the greatest factor in the movement rates. It is, however, a factor and should be discussed, if at least in terms of the 'debate'. As I understand it, basal drag has traditionally been considered a considerable force, too. In fact, unless I understand it incorrectly, Hess considered this force to be what caused rifting in the first place because of the force that a laterally moving convection current exerts upon the crust. 124.171.62.71 ( talk) 08:58, 26 August 2014 (UTC)
This process (without a sea) appears not to occur on any other planet or moon in the solar system. [See section 9 of Plate tectonics]. Is that worth mentioning? -- Tediouspedant ( talk) 23:04, 6 March 2010 (UTC
There are no pictures of geysers on Europa. So it appears not. I've seen no evidence of plates on the moon. I've seen no evidence of plates on earth, only earthquakes - which could just as easily by tidal forces on land. Why is this a thing?
Earth expands... sea floor spreads... continents move further apart... continents flatten... intra-plate earthquakes... d'oh! It's sooo obvious but too hard to go back and admit plate tectonics is shite! — Preceding unsigned comment added by 202.162.74.172 ( talk) 06:45, 24 August 2011 (UTC)
In the lead we find this phrase:
It is not clear to from the text in the lead if convection is happening in the asthenosphere it self or in the mantle under it. For me it seems more likely that the astenosphere is the boundary layer between convecting mantle and rigid lithospheric mantle. That part of lead does cite a 1971 paper, I would suspect there are newer sources that are more clear and assertive on the subject.
— Lappspira ( talk) 00:15, 2 October 2016 (UTC)
Because this section deals largely with mid-ocean ridge depth profiles I suggest it be moved to the mid-ocean ridges article. BrucePL ( talk) 19:10, 29 March 2018 (UTC)
@ Dan Gluck: Good grief! Has it been over a year since we corresponded about this? I just did a bunch of edits on the MOR page and was reminded of the half-space chat we had. I'll set about copying the model to MOR with a link on SFS article to the model section on MOR. BrucePL ( talk) 16:46, 17 September 2019 (UTC)
This section is now on its own page Seafloor depth versus age. I will do some consolidating of this section and delete the math because it is now on its own page. Links on this page will direct reader to the details on the new page. BrucePL ( talk) 00:05, 31 January 2020 (UTC)
What does determine the direction and drift of lithosphere plates ? And what does give the force to move the plates and what is a reason that somewhere arise a knew Rift ? So what is the reason, that somewhere the lithosphere-plate is heating up ? I would say it's the Mantle Convection, but the german Wikipedia says, it's not that. it's the weight of the plates. I think that's not true.
Sorry for my english. — Preceding unsigned comment added by 2A02:1203:ECBD:A300:5D01:CC46:C2D6:57D2 ( talk) 07:37, 31 October 2018 (UTC)
I worked on this section adding the cooling plate model for seafloor depth (and crustal heat flow). I suggest that this topic be made its own page and creating short content on the Seafloor Spreading (and Mid-ocean ridge page) that directs a reader to the new page.
My thinking is that the derivation of the cooling mantle model is fairly advanced; it includes solving partial differential equations, not usually encountered in WP STEM pages.
The derivation is useful, however, as it includes fundamental principles of solving differential equations by setting boundary conditions and approximations.
Thoughts anyone? BrucePL ( talk) 19:45, 26 November 2019 (UTC)
The physical phenomena of convection includes any case where in one part you have hot matter that ascends, then cools down and goes down in another part. When it is not driven by the temperature difference it is called forced convection, but it is still convection. Anyway, as far as I understand, plate tectonics is in fact driven by temperature differences, so it is a regular convection and not forced - this is true whether it is driven by slab pull due to the margins being cold (after cooling down) or by ridge push due to hot material ascending from below, or due to mantle convection (with the latter option probably not true). Dan Gluck ( talk) 18:35, 25 September 2020 (UTC)