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Author Topic:   Heat release from tectonic friction
PaulK
Member
Posts: 13112
Joined: 01-10-2003
Member Rating: 2.7


Message 61 of 102 (684308)
12-17-2012 1:58 AM
Reply to: Message 58 by Faith
12-17-2012 1:25 AM


Re: Faith and Science
quote:

I'm on record here in a number of places including nonYEC's among "real Christians" so you are wrong about that. While I think Genesis is extremely important to the gospel itself, I've allowed that there are probably true believers who give in to science on that, although they shouldn't and I think it's sad that this has happened. I regard them as "real Christians" if they hold to the doctrines of salvation nevertheless

You're also on record as saying that they SHOULDN'T be Christians....

Message 198


That Black Sea stuff is an accommodation to the OE paradigm. The Bible SAYS "the whole world," that MEANS the WHOLE WORLD. You've bought the OE. You'd be a lot better off if you just gave up the Bible, because it's a great sin to try to conform it to such nonsense. Go whole hog and become a secular geologist, you'll be a lot safer. Maybe later on if there's still time you can rethink it all and come back to the Bible. A compromised Bible is worse than no Bible.

If it's better to be a non-believer than a non-YEC Christian it's hard to see how you can count non-YECs as "real Christians". Certainly you can't accept that there is any possibility that they are saved. Which is odd really as there's nothing in the Bible to say that salvation depends on accepting YEC views.

{Science topic people, not a Bible study topic. - Adminnemooseus

Edited by Adminnemooseus, : Off-topic banner and big red text.


This message is a reply to:
 Message 58 by Faith, posted 12-17-2012 1:25 AM Faith has not yet responded

    
edge
Member
Posts: 3964
From: Colorado, USA
Joined: 01-09-2002
Member Rating: 3.7


Message 62 of 102 (684440)
12-17-2012 3:30 PM
Reply to: Message 59 by TrueCreation
12-17-2012 1:37 AM


Re: Back of envelope calculation
Well it is precisely the 'surrounding rocks' which are cooling. Here is a 2D (average transect with age) tomographic inversion for upper mantle temperature over Pacific oceanic lithosphere as a function of lithospheric age: http://ciei.colorado.edu/...piro_research_files/image003.jpg
This thermal structure is clearly a consequence of gradual conductive cooling of the upper mantle with age, corroborated by many other geophysical observations in addition to seismic tomography. No other physical mechanism can account for these observations.

TC, you are touching on an important point here. IMHO, the frictional heating is almost irrelevant. The reason is that all we have done on the oceanic lithosphere formation and conveyance, is convert the original convective magmatic heat from the mantle into conductive heat in the crust which ulltimately flows to the ocean and atmosphere and eventually radiates into space.

Simply put, the earth is cooling. Any frictional heat is minor and transient. The end result is the same: a cooling planet.

I suggest the way to attack the heat problem is to calculate the average current heat flow from the earth and project that 4.5 ga into the past (this would be a minimum number since the heat flows of the distant past were certainly much higher - so we are only getting an end-member here).

Okay, now compress that amount of heat into 6ky and see what happens.

By the way, I'm not so sure that your statement about where the heat-forming radioelements are found is correct. While many of the elements are found in continental crust, where we can extract them, there is some consensus that the core is another concentration of radionuclides such as thorium and uranium. After all, what causes heating of the mantle plumes?


This message is a reply to:
 Message 59 by TrueCreation, posted 12-17-2012 1:37 AM TrueCreation has responded

Replies to this message:
 Message 66 by TrueCreation, posted 12-18-2012 4:14 AM edge has not yet responded

  
Dr Adequate
Member
Posts: 15950
Joined: 07-20-2006
Member Rating: 4.6


(1)
Message 63 of 102 (684483)
12-17-2012 4:52 PM
Reply to: Message 55 by Faith
12-16-2012 10:25 PM


Re: Faith and Science
That is not a Biblical viewpoint, that was the pagan view of Aristotle that came into the ROMAN church via Aquinas.

It was a view espoused by the Protestant reformers, you know. Here's what they had to say about heliocentrism.

"This fool wishes to reverse the entire science of astronomy; but sacred Scripture tells us that Joshua commanded the sun to stand still, and not the earth." --- Martin Luther.

"Who will venture to place the authority of Copernicus above that of the Holy Spirit?" --- John Calvin, Commentary on Genesis.

"Now, it is a want of honesty and decency to assert such notions publicly, and the example is pernicious. It is the part of a good mind to accept the truth as revealed by God and to acquiesce in it." --- Melanchthon.

Edited by Adminnemooseus, : Off-topic banner.


This message is a reply to:
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Dr Adequate
Member
Posts: 15950
Joined: 07-20-2006
Member Rating: 4.6


Message 64 of 102 (684485)
12-17-2012 4:53 PM
Reply to: Message 53 by Faith
12-16-2012 8:17 PM


Re: Faith and Science
That was the standard historical Christian understanding of Genesis for all orthodox believers back to the beginning (with the exception of Augustine and a few others who had an allegorical understanding of it).

So, all of them except for the exceptions.

Edited by Dr Adequate, : No reason given.

Edited by Adminnemooseus, : Off-topic banner.


This message is a reply to:
 Message 53 by Faith, posted 12-16-2012 8:17 PM Faith has not yet responded

  
Adminnemooseus
Director
Posts: 3825
Joined: 09-26-2002
Member Rating: 1.8


Message 65 of 102 (684532)
12-17-2012 7:10 PM


Random act of moderation - Not a Bible study topic
I've "Off-topic" bannered a few messages. More could be done such, going upthread.

People - Science topic, not a Bible study topic.

Adminnemooseus

ABE - OK, I later found that Faith has diverted the off-topic stuff to the Off Topic Posts aka The Rabbit Trail Thread topic.

Edited by Adminnemooseus, : ABE.


Or something like that.

    
TrueCreation
Inactive Member


Message 66 of 102 (684607)
12-18-2012 4:14 AM
Reply to: Message 62 by edge
12-17-2012 3:30 PM


Re: Back of envelope calculation
quote:
I suggest the way to attack the heat problem is to calculate the average current heat flow from the earth and project that 4.5 ga into the past (this would be a minimum number since the heat flows of the distant past were certainly much higher - so we are only getting an end-member here).

Okay, now compress that amount of heat into 6ky and see what happens.

By the way, I'm not so sure that your statement about where the heat-forming radioelements are found is correct. While many of the elements are found in continental crust, where we can extract them, there is some consensus that the core is another concentration of radionuclides such as thorium and uranium. After all, what causes heating of the mantle plumes?



The exercise of constraining the thermal history of the Earth given known present-day surface heat flow has been the subject of much interest in geophysics for a long time, and happens to be a major interest of my own. The primary factors which present difficulties for such calculations is the uncertainty in bulk Earth concentrations of the major heat producing elements, the fraction of surface heat flow originating in radiogenic sources in continental crust, and uncertainty in scaling laws for temperature-dependent rheology of the mantle (as temperature increases, viscosity decreases). The last of these has been given much more attention than the first two probably because a solution to this problem is a critical commentary on the fundamental nature of mantle convection.

Incidentally, it should be of great interest to creationists that a long known problem with mantle viscosity scaling laws is that conventional scaling with conventional constraints on the present-day cooling rate of the Earth (around 50-120 K/Gyr), extrapolation into the past results in an exponentially increasing cooling rate of the mantle, until the whole mantle essentially melts. You need to go back in time at least a billion years to arrive at thermal catastrophe, but I'm sure YEC's like Baumgardner and Snelling would still jump all over this. Nevertheless, the conventional scalings are very simplistic and certainly wrong for many reasons related to coupling behavior of lithosphere and mantle and the like. I've just submitted a paper showing that the surface heat flux over seafloor is about 10-25% lower than conventional estimates, significantly changing an important boundary condition for thermal history calculations. In addition, I am in the middle of investigating a coupled thermal evolution and isostatic model of the Earth to estimate eustatic sealevel changes from present-day to the Archean. I should be able to show that the thermotectonic behavior of oceanic lithosphere (e.g. plate velocity) is not compatible with conventional scalings.

Nevertheless, while I can't do the calculation now, the convective scaling doesn't matter for the young-earth hypothesis because even if the Earth were completely melted convective transport will not be able to transport nearly enough mantle heat and is irrelevant for transport of heat generated in continental crust.

Finally, you doubt my comment on the concentrations of the major heat producing radioisotopes. First, I compared the concentration of radioisotopes in the mantle and continental crust, which I don't think is contrary to prevailing thought. Second, my understanding is that the consensus regarding concentrations in the core is that thorium and uranium almost certainly do not have an elevated concentration (they are strongly lithophile even at high pressure/temperature), but the jury is still out on concentrating potassium. Nevertheless, it is not clear if such a concentration in the core is necessary. It is known that at least some heat (something like 5-11 TW) must originate in the core to drive the geodynamo and maybe (a big maybe, in my opinion) drive mantle plumes, but this does not require radiogenic sources. Release of latent heat and gravitational potential energy associated with inner core growth might be enough. There are also mineral physics problems associated with estimating thermal core-mantle interaction because the thermal conductivity across D'' is not well understood.

Anyways, the point is that since radioisotopes are preferentially concentrated in continental crust, the crust will be melted and vaporized long before the mantle temperature changes significantly from accelerated decay.

Edited by TrueCreation, : No reason given.


This message is a reply to:
 Message 62 by edge, posted 12-17-2012 3:30 PM edge has not yet responded

  
kofh2u
Member (Idle past 1348 days)
Posts: 1162
From: phila., PA
Joined: 04-05-2004


Message 67 of 102 (684653)
12-18-2012 11:05 AM
Reply to: Message 49 by TrueCreation
12-16-2012 2:56 AM


Re: Back of envelope calculation

quote:
--------------------------------------------------------------------------------
Those are al resistive forces.
You are trying to calculate all the possible Forces that resist the motion.
The energy that it takes to move the weight of the plates through the distance of whatever is the case, over a period of unit time ought give us the answer, right?

E = 1/2mv^2?

--------------------------------------------------------------------------------

Yes, this is the formula I have used. The distance is only important inasmuch as it is related to velocity.

All the required varibles in the equation can be discovered rather easily in that the mass of the lithosphere has been estimates, I am certain, and we know how long it was between the first time "all the waters under heaven were gathered together into one place" in the event of Rodinia and the time lapse until Pangea formed.

That would give us the time from the break up of the very first super continent surrounded by one singular panthallassic Ocean until the same condition appeared with Pangea.

All these other idea suggested above are lame and unworkable, at best merely confirming that the sum energy used over the time must be less than all these combined resistive forces in play.

End of thread????

Unless you have a number as an answer...


This message is a reply to:
 Message 49 by TrueCreation, posted 12-16-2012 2:56 AM TrueCreation has responded

Replies to this message:
 Message 68 by TrueCreation, posted 12-18-2012 4:54 PM kofh2u has responded

    
TrueCreation
Inactive Member


Message 68 of 102 (684792)
12-18-2012 4:54 PM
Reply to: Message 67 by kofh2u
12-18-2012 11:05 AM


Re: Back of envelope calculation
quote:
Unless you have a number as an answer...

I have already estimated the heat released by cooling of (presently exposed/active) oceanic lithosphere in Message 25 as on the order of 10^29 J. Then, in Message 28, I estimated the heat released from slowing plate tectonics from 0.3 m/s to 0 m/s as on the order of 10^22 J. Obviously the first number is more important for YEC's because it is far greater and, unless you want to appeal to magic, must be transferred through the oceans. Do you dispute this?

Edited by TrueCreation, : No reason given.


This message is a reply to:
 Message 67 by kofh2u, posted 12-18-2012 11:05 AM kofh2u has responded

Replies to this message:
 Message 69 by kofh2u, posted 12-19-2012 11:09 AM TrueCreation has responded

  
kofh2u
Member (Idle past 1348 days)
Posts: 1162
From: phila., PA
Joined: 04-05-2004


Message 69 of 102 (684922)
12-19-2012 11:09 AM
Reply to: Message 68 by TrueCreation
12-18-2012 4:54 PM


Re: Back of envelope calculation

I have already estimated the heat released by cooling of (presently exposed/active) oceanic lithosphere in Message 25 as on the order of 10^29 J. Then, in Message 28, I estimated the heat released from slowing plate tectonics from 0.3 m/s to 0 m/s as on the order of 10^22 J. Obviously the first number is more important for YEC's because it is far greater and, unless you want to appeal to magic, must be transferred through the oceans. Do you dispute this?

Dispute is the wrong word.

I tend to believe your figures of 10^22Joul, because it seems straight forward and simply physics.

I am not so sure of "estimated the heat released by cooling" because there seems to be too many mitigating factors that must be estimated or inferred.

Of course, if this were important to me as it seems to be to you who are writing a paper on the matter, more attention to your mathematics and deductions could convince me, I am sure.

But if the two numbers were closer, the cooling would essentially be a double check against the mechanical energy, which I tend to accept based on the confidence in your physics for E = mv^2/2.

Edited by kofh2u, : No reason given.

Edited by kofh2u, : No reason given.


This message is a reply to:
 Message 68 by TrueCreation, posted 12-18-2012 4:54 PM TrueCreation has responded

Replies to this message:
 Message 72 by TrueCreation, posted 12-19-2012 3:56 PM kofh2u has responded

    
kofh2u
Member (Idle past 1348 days)
Posts: 1162
From: phila., PA
Joined: 04-05-2004


Message 70 of 102 (684926)
12-19-2012 11:26 AM
Reply to: Message 1 by Trixie
12-07-2012 8:29 AM


Catch 22

I'm looking for some assistance (read as please do the calculations for me and tell me the answer) in determining the heat effects of all of earth's tectonic activity, or as much of it as is known, being crammed into 4000 years. I have a sneaking suspicion that it would have melted the crust.
What factors would need to be taken into account and what would be the effects of the other forms of energy released?

In order to sell this argument to YECs they would need to accept tectonic plate movement and the theory of cyclic movement that created Rodinia, then Pangea millions of years ago.
Since to them that would be an oxymoron, to use facts based upon the assumption of a very old Earth to disprove the belief in a very young earth.

Right?

They would have to accept your premise of a old earth before your evidence was useful to disprove a very young earth.

Since Gen 1:9 explicitly reports that, at least once, "all the waters under heaven were collected together into one place," a de facto initial case of Panthallassic ocean and Pangea existed.

We need show the time necessary to separate the continents as we observe them today.
We need show the rate these plates move apart and how long it took to form the seven continents of this moment.

That ought be easier.
Time, not energy.

But it also shows they did not read Gen 1:9 and realize it refers to Pangea.
Just that ought be enough to show YECs they misinterpret Genesis.

Gen. 1:9 And (Father Nature, the first cause), God, said, Let the waters under the heaven be gathered together unto one place, (Panthalassa), and let (Pangea/Rodinia), the dry land appear: (composed of the Seven Large Tectonic Plates):

1. North American Plate,
2. Pacific Plate,
3. South American Plate,
4. African Plate,
5. Eurasian Plate,
6. Anartic Plate,
7. Australian Plate),...

...and it was so.

(Gen 1:9)


This message is a reply to:
 Message 1 by Trixie, posted 12-07-2012 8:29 AM Trixie has not yet responded

Replies to this message:
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Eli
Member (Idle past 1020 days)
Posts: 274
Joined: 08-24-2012


(1)
Message 71 of 102 (684941)
12-19-2012 12:47 PM
Reply to: Message 70 by kofh2u
12-19-2012 11:26 AM


Re: Catch 22
This has been thoroughly covered in your "six geological eras" thread.

Please refrain from discussing your ideas on Pangea as they have already been explored and debunked. You don't know the topic and you spread false information despite your own ignorance of the subject.

Substituting one false reality for another will not help the YEC's.

This is also a tangent point for you to launch into an off-topic discussion. This is a warning: I will report you if you begin talking about hominids, stages of the universe, Freud, or whatever else you have packed away that is not related to the topic "heat release from tectonic friction."

Edited by Eli, : No reason given.


This message is a reply to:
 Message 70 by kofh2u, posted 12-19-2012 11:26 AM kofh2u has not yet responded

  
TrueCreation
Inactive Member


(1)
Message 72 of 102 (684962)
12-19-2012 3:56 PM
Reply to: Message 69 by kofh2u
12-19-2012 11:09 AM


Re: Back of envelope calculation
quote:
Dispute is the wrong word.

I tend to believe your figures of 10^22Joul, because it seems straight forward and simply physics.

I am not so sure of "estimated the heat released by cooling" because there seems to be too many mitigating factors that must be estimated or inferred.

Of course, if this were important to me as it seems to be to you who are writing a paper on the matter, more attention to your mathematics and deductions could convince me, I am sure.

But if the two numbers were closer, the cooling would essentially be a double check against the mechanical energy, which I tend to accept based on the confidence in your physics for E = mv^2/2.



Well, it should be of interest to you because explaining the first-order thermal state of the upper mantle is pretty much the most basic and informative observation in all of plate tectonics.

The two numbers are not close because cooling is a transport of internal energy, whereas the mechanical part is a transfer of kinetic energy. The gradual migration and cooling oceanic lithosphere with distance and age from spreading centers is one of the best established processes in all of geophysics since the observations which constrain it are simple and massively corroborated by different field observations and experimental constraints on the actual properties of the Earth. There are lots of uncertainties, but the uncertainties change results by percent, not orders of magnitude, let alone six orders of magnitude.

A pretty good introductory survey of the problem is here:

http://topex.ucsd.edu/geodynamics/07cooling.pdf

Also consider this page by Joe Meert, who addresses the problem of explaining seafloor topography (since it is related to the temperature of oceanic lithosphere) for YEC's:

http://gondwanaresearch.com/oceans.htm

Also, you can take a look at a recent paper I published here:

https://dl.dropbox.com/...f%20oceanic%20lithosphere_EPSL.pdf

I use numerical techniques to solve the cooling problem, which is, at least to me, far simpler than analytic techniques, especially when you introduce certain complexities like temperature-dependent heat transport properties.


This message is a reply to:
 Message 69 by kofh2u, posted 12-19-2012 11:09 AM kofh2u has responded

Replies to this message:
 Message 73 by kofh2u, posted 12-19-2012 9:45 PM TrueCreation has responded

  
kofh2u
Member (Idle past 1348 days)
Posts: 1162
From: phila., PA
Joined: 04-05-2004


Message 73 of 102 (684990)
12-19-2012 9:45 PM
Reply to: Message 72 by TrueCreation
12-19-2012 3:56 PM


Re: Back of envelope calculation
It interesting.

I would expect that the actual energy necessary to move the plates a specified distance over a specific time interval would be higher than the measurement of the transfer energy which is a conversion from the former mechanical form, and it would also be a sum that ignores the energy required to push up the massive rock layers and other geological effects.

Perhaps I would discover that I am not analyzing the problem correctly if I had time to read your links, but isn't the mechanical energy the real determinant here?
It ought be larger by far than the thermal conversions you are adding up.


This message is a reply to:
 Message 72 by TrueCreation, posted 12-19-2012 3:56 PM TrueCreation has responded

Replies to this message:
 Message 74 by TrueCreation, posted 12-20-2012 1:53 AM kofh2u has responded

    
TrueCreation
Inactive Member


Message 74 of 102 (685018)
12-20-2012 1:53 AM
Reply to: Message 73 by kofh2u
12-19-2012 9:45 PM


Re: Back of envelope calculation
Mantle convection is driven by thermal buoyancy forces which originate in cooling at the surface, not a different mechanical source. Unless the Earth contracts or is acted on by an external force, kinetic energy available for plate tectonics at the surface originates in a conversion from the internal energy by mantle convection.

A nice comprehensive review-style paper of some of the fundamentals of the thermodynamics of the Earth is given by Jaupart et al here:

http://perso.ens-lyon.fr/...PDF/JaupartLabrosseMareschal.pdf


This message is a reply to:
 Message 73 by kofh2u, posted 12-19-2012 9:45 PM kofh2u has responded

Replies to this message:
 Message 77 by kofh2u, posted 12-20-2012 9:56 AM TrueCreation has responded

  
TrueCreation
Inactive Member


Message 75 of 102 (685021)
12-20-2012 2:17 AM
Reply to: Message 57 by ICANT
12-17-2012 1:13 AM


Re: Back of envelope calculation
quote:
There happens to be enough water in the lithosphere, asthenosphere and mantel to fill our oceans 7 times. That water had to get there some way, and sometime in the existence of the Earth.

You're right. Although, perhaps a more useful question is why the water remains there. How it got there may be more of a cosmochemical question, although we know that at least some water is continually carried into the mantle by subduction. But why it remains there and is not completely degassed is a geochemical one. There is a lot of water (albeit in low concentration) in the mantle simply because water is soluble in major mantle minerals like olivine and pyroxenes at most mantle pressures.

I don't see what your point is, though.

Edited by TrueCreation, : No reason given.


This message is a reply to:
 Message 57 by ICANT, posted 12-17-2012 1:13 AM ICANT has responded

Replies to this message:
 Message 76 by ICANT, posted 12-20-2012 9:49 AM TrueCreation has responded

  
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