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Member (Idle past 1434 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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Author | Topic: Mid-ocean Ridges and Age of Formation | |||||||||||||||||||||||||||||||||||||||
RAZD Member (Idle past 1434 days) Posts: 20714 From: the other end of the sidewalk Joined:
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I may not be the best source to initiate this, as my knowledge of geology is weak.
That said I come to this topic as a side issue from Geology and the Great Flood, Why the Flood Never Happened, Message 290 where Faith is asking questions about Tectonics. It occurs to me that a basic discussion of the mid-ocean ridges would help in
It occurs to me that these ridge patterns are like tree rings and varves ... Mid-ocean ridge - Wikipedia
The mechanism behind Plate Tectonics
quote: Presumably the ridges are date-able by radiometric means, and there should be a number of different techniques to use so they can be checked for consilient dates. Enjoy Edited by RAZD, : image addedby our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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AdminNosy Administrator Posts: 4754 From: Vancouver, BC, Canada Joined:
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Thread copied here from the Mid-ocean Ridges and Age of Formation thread in the Proposed New Topics forum.
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RAZD Member (Idle past 1434 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Just a quick search gets me these two articles
(1) Steven J. Goldstein, Michael T. Murrell, Ross W. Williams, 231Pa and230Th chronology of mid-ocean ridge basalts, Earth and Planetary Science Letters, Volume 115, Issues 1—4, March 1993, Pages 151—159, Error: DOI Not Found(93)90219-Y
quote: and (2) R. A. Duncan, L. G. Hogan, Radiometric dating of young MORB using the 40Ar-39Ar incremental heating method, Geophysical Research Letters, Volume 21, Issue 18, pages 1927—1930, 1 September 1994, Article first published online: 7 DEC 2012, DOI: 10.1029/94GL01375 Just a moment...
quote: Seems to be more about method than results. MORB is mid ocean ridge basalt. Enjoy. Edited by RAZD, : ..by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1434 days) Posts: 20714 From: the other end of the sidewalk Joined: |
From NOAA
Mid-Ocean Ridge Activity
quote: Looks like the ocean floor age varies from 0 at the ridges to 180 million years at the furthest subduction zone. This map is similar: http://geology.about.com/...cmaps/ss/World-Seafloor-Ages.htm
quote: The oldest shown here is ~280 million years between Africa and Italy/Greece/Turkey. Enjoyby our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Stile Member Posts: 4295 From: Ontario, Canada Joined: |
RAZD writes: The oldest shown here is ~280 million years between Africa and Italy/Greece/Turkey. Probably because the Mediterranean sea is so protected from the rest of the ocean formation? Everywhere else has newer stuff being created and eventually flowing overtop... but here, it is sort of "locked off" and doesn't get backfilled. Something like that?
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RAZD Member (Idle past 1434 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Probably because the Mediterranean sea is so protected from the rest of the ocean formation? More likely that it is the last remnant of ocean floor being pushed under as the gap between narrows.
Everywhere else has newer stuff being created and eventually flowing overtop... but here, it is sort of "locked off" and doesn't get backfilled. The floors are part of the plates moving away from the ridge, which causes the crack for new stuff to well up, solidify and start traveling with one or the other plate. The further away the older they are, having moved away from the center gap in the intervening years. Mid-ocean ridge - Wikipedia
Something like that? Not quite ... by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Pollux Member Posts: 303 Joined: |
Associated with plate tectonics are the many chains of islands and underwater mountains, formed as the plates moved over a hot spot of magma. This created volcanoes that built the mounts, and that died as the plate moved further away. The Hawaiian-Emperor chain is the best known one. Most of these show a linear increase in radiometric age as you move away from the hot spot, consistent with currently observed rates of movement of the plates, thus being a check on the accuracy of RM dating.
Fitting in all the tectonic movement during or post-Flood is a major problem for YEC. (With all the earthquakes Noah would not have been able to stand up, let alone plant a vineyard!) Adding the consistency of RM dates must be a killer!
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RAZD Member (Idle past 1434 days) Posts: 20714 From: the other end of the sidewalk Joined: |
... This created volcanoes that built the mounts, and that died as the plate moved further away. ... And they should have recorded the magnetic field orientation that was current at that time, so should correlate with bottom age and magnetic field. Can you imagine all those magnetic field inversions occurring in a YEC model world? Enjoy.by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Pollux Member Posts: 303 Joined:
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Well of course all those magnetic reversals have to occur in a YEC model. Usually the tectonic movements are at the end and /or soon after the flood. So you have the plates whizzing around at miles per day, stupendous vulcanism to build the seamounts, oceanic crust, Deccan traps etc, radiogenic decay rates hyperaccelerated without heat problems, then you need an ice age afterward, to finish in time to build the pyramids. So much to do, so little time!
But wait. The evidence of the direction of the movement of ice in Southern Africa, South America, and Australia did not make sense until Weggener proposed continental drift, and it was realised the ice was there BEFORE the continents broke up. Oh dear. As Fagin said in Oliver, I think I'd better think it out again! It must have been easier being a Flood "geologist" before so many inconvenient facts were discovered.
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RAZD Member (Idle past 1434 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Associated with plate tectonics are the many chains of islands and underwater mountains, formed as the plates moved over a hot spot of magma. This created volcanoes that built the mounts, and that died as the plate moved further away. The Hawaiian-Emperor chain is the best known one. Most of these show a linear increase in radiometric age as you move away from the hot spot, consistent with currently observed rates of movement of the plates, thus being a check on the accuracy of RM dating. And I was able to find this http://www.geog.fu-berlin.de/...KIV/hawaii/introduction.html
quote: Doesn't appear to include a magnetic reversal. Against that "standard" Hawaii Island theory is this: The Emperor and Hawaiian chains
quote: It seems that there is some dispute here, and that magnetic alignment with ridge spreading lines of magnetic orientations is part of the discussion. Enjoyby our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Pollux Member Posts: 303 Joined:
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I read in recent months that the bend in the chain is due to migration south of the hot spot, while the plate was moving NW. This was indicated by magnetic evidence of the more distant mounts being formed at higher latitudes. This seems much more likely than the previous idea that the plate rotated. I guess there is still a great deal to learn about the inner Earth.
There are other sea mount chains that show the same increase in age as you go along them. Also there are old volcanoes in the Australian Great Dividing Range that also increase in age consistent with the rate of movement of the plate. The hot spot is thought to be in Bass Strait and weaker than previously.
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Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
Usually the tectonic movements are at the end and /or soon after the flood. So you have the plates whizzing around at miles per day, No, not miles per day, not even miles per year. Some time ago I calculated the speed at which the tectonic plates would be separating based on their having begun to separate at the time of the Flood, and came up with 20 FEET per day as the starting speed -- or one and a half miles or 7920 feet per YEAR, or 600 feet per month or 20 feet per day. The average speed would have been 11 feet per day. All bringing us to the current two to four inches per year as estimated by evolution writer Jerry Coyne. Is 20 feet per day such an outlandishly fast rate? That's ten feet of separation on either side of the mid-Atlantic ridge being generated daily or less than 6 inches hourly. Again, at the beginning of the movement.
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Coyote Member (Idle past 2135 days) Posts: 6117 Joined:
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Is 20 feet per day such an outlandishly fast rate? That's ten feet of separation on either side of the mid-Atlantic ridge being generated daily or less than 6 inches hourly. Yes. "Ranges of Spreading throughout the world's oceans: 1 cm/yr to 10 cm/yr." Calculating Sea Floor Spreading When the rates vary between 1 and 10 cm per year, your rate of ca. 600 cm per day is pretty silly. And the funniest part is you don't have any evidence to support it. You're just making it all up as you go.Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge. Belief gets in the way of learning--Robert A. Heinlein How can I possibly put a new idea into your heads, if I do not first remove your delusions?--Robert A. Heinlein It's not what we don't know that hurts, it's what we know that ain't so--Will Rogers If I am entitled to something, someone else is obliged to pay--Jerry Pournelle If a religion's teachings are true, then it should have nothing to fear from science...--dwise1
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Faith  Suspended Member (Idle past 1473 days) Posts: 35298 From: Nevada, USA Joined: |
I figured a distance of 3000 miles (roughly that between Europe and North America) that had to be covered in 4300 years ending at a speed of two to four inches per year. That is what gave me the 20 feet per day starting speed.
Edited by Faith, : No reason given. Edited by Faith, : No reason given.
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Tanypteryx Member Posts: 4451 From: Oregon, USA Joined: Member Rating: 5.0 |
Faith writes: I figured a distance of 3000 miles (roughly that between Europe and North America) that had to be covered in 4300 years ending at a speed of two to four inches per year. That is what gave me the 20 feet per day starting speed. When did it slow down to the rate we have now? Would Ben Franklin have noticed it? Did anyone notice it and write about it?What if Eleanor Roosevelt had wings? -- Monty Python One important characteristic of a theory is that is has survived repeated attempts to falsify it. Contrary to your understanding, all available evidence confirms it. --Subbie If evolution is shown to be false, it will be at the hands of things that are true, not made up. --percy
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