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Author Topic:   Geomagnetism and the rate of Sea-floor Spreading
Admin
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Message 196 of 234 (181332)
01-28-2005 10:36 AM


Forum Guidelines Warning
I am concerned that I am finding too many violations of rule 3 of the Forum Guidelines:
  1. Respect for others is the rule here. Argue the position, not the person. The Britannica says, "Usually, in a well-conducted debate, speakers are either emotionally uncommitted or can preserve sufficient detachment to maintain a coolly academic approach."
The responsibility for following the guidelines lies with members. The responsibility for enforcing the guidelines and noting violations lies soley with moderators. Not liking someone's approach or tone is not a license for violating the guidelines. The sole judge of whether something constitutes a violation is a moderator. Members should not set themselves up as both debater and moderator.
I'm not going to be specific at this time, so I won't answer questions. Anyone wondering whether the impetus behind this message was due to anything they posted should go back and reread their own messages.

--Percy
EvC Forum Director

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Jazzns
Member (Idle past 3911 days)
Posts: 2657
From: A Better America
Joined: 07-23-2004


Message 197 of 234 (181364)
01-28-2005 12:01 PM
Reply to: Message 192 by Hydroplate Hippie
01-28-2005 4:11 AM


Geo 101 Plate Tectonics vs Hydroplate
I have a couple of questions for HH and anyone else who would like to pipe in. If possible, I would like a real geologist to confirm what I remember from my scant two semesters of geology courses.
In class I remember discussing the magnetic stripes and going through a list of evidences for why we are pretty sure they are caused by sea floor spreading and why the speed of plate movement has been constant within a range of very low values.
1) Symmetry
One of the best evidences I took for why the magnetic stripes are certainly caused by spreading is the symmetry of the reversals as you move in both directions from a mid ocean ridge. They are symmetrical both in their order and in their width. Wouldn't any alternate explanation of the magnetic data also have to account for symmetry before sea floor spreading can be overturned?
2) The Age of Mountains
When you piece back all the continents into Pangaea you can notice that the Appalachians and other mountain chains in Europe/Scandinavia look very much to be a part of the same mountain building event. I am pretty sure there is actually some pretty convincing mineral analysis that supports this knowledge but I cannot recall at the moment the details.
These mountains were obviously split at the rift point however the details of the plate tectonics. It is interesting then to look at the other side of North America where it meets another tectonic boundary of the opposite kind. The eastern part of the plate is part of a divergent boundary while the west part of the plate is part of a convergent boundary which in particular is a subduction zone.
Ignoring other geologic evidence for the age of mountains, one would have to explain why the Rockies are less weathered (younger) than the drastically weathered by comparison Appalachians (older). Using the current widely accepted theory of plate tectonics the answer is because it took a long time to form the Rockies (still forming) and meanwhile the Appalachians had that time to erode to their current state.
In a young earth where rapid plate tectonics took place the mountains should be relatively the same age. Why then would we have such a disparity in weathering rates over just a few thousand years? The classical answer should be that plate tectonics happened slowly.
3) Biogeography
Particularly marsupial biogeography. Extant and fossil marsupials have only existed in certain geographic environments. In particular, as you extrapolate through geologic time, the ancestors to current day marsupials were exclusively located in South Africa, Antarctica, Australia and South America. As species were geographically separated due to plate tectonics, marsupial species diverged in their respective isolated areas. Assuming that a proto-marsupial "kind" cannot "micro evolve" into a kangaroo in a weekend, this process was slow.
Also, someone please confirm this, I believe that marsupial migration into North America only became possible once North and South America became connected via Panama. Therefore we can time the diversification of marsupials into North America with the data from plate movement. The conclusion is that plate tectonics is a slow process.
4) Hawaii
The classical theory regarding the formation of Hawaii is that the Pacific plate is moving over a hot spot to which the subsequent volcanism has created a chain of islands. Loudmouth had a great thread on this YEC Challenge: Hawaiian Islands discussing all the wonderful correlations. This is great evidence that the Pacific plate motion has been slow for quite some time.
Overall, any theory of rapid plate tectonics would have to explain these things. How does the Hydroplate Hypothesis address these in order to overturn the classical model regarding plate tectonics?

Now is the winter of your discontent!
-- Stewie Griffin

This message is a reply to:
 Message 192 by Hydroplate Hippie, posted 01-28-2005 4:11 AM Hydroplate Hippie has replied

Replies to this message:
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Joe Meert
Member (Idle past 5680 days)
Posts: 913
From: Gainesville
Joined: 03-02-2002


Message 198 of 234 (181375)
01-28-2005 1:26 PM
Reply to: Message 192 by Hydroplate Hippie
01-28-2005 4:11 AM


Re: Marine magnetic anomalies
"HH" writes:
Perhaps you could take the concerns I raised (in post 144) about the scientific legitimacy of a proposed geodynamo and geomagnetic field reversals to your colleagues.
JM: Of course it's legitimate science to determine how the Earth's magnetic field is generated and reverses. They are both real puzzles. However, although we don't yet know the answer to either question, the fact that the Earth has a magnetic field and that the field reverses are not in question. The body of scientific evidence for both is overwhelming. As to your points 1,2 and 3: You are being a bit disingenous with several of your questions. Statements like:
"HH" writes:
there is no mechanism to generate the large electrical currents within the proposed geodynamo that could produce the geomagnetic field.
JM: are useless and misleading. The first problem is that you make the assumption that because we do not yet have an answer, then all proposals should be taken as equal. That is not true. The second assumes that that we do not have any proposed mechanisms for generating a field. Dynamos have been known for a long time and Maxwell's equations tell us quite simply that a moving current will produce a magnetic field and that moving a magnetic field in a conducting medium will produce a current. The more important question is does the Earth's magnetic field behave like a dynamo (even if we don't know the particulars). The answer is a resounding YES! We know from paleomagnetic studies that the Earth has a magnetic field as far back as 3 billion years and that it periodically reverses. We know that a static field cannot be maintained for that amount of time and a static field will not produce reversals. You can argue about the stripes on the ocean floor to your hearts content, but we DO observe normal and reverse polarities in rocks. We can also test these rocks to see whether or not they are self-reversing. In all but a very few cases (Haruna dacite) we know that they are not. The only mechanism to sustain a reversing field for 3+ billion years is via a dynamo. Saying that there is no known mechanism is false, you should more accurately state that there are many known mechanisms, but we don't yet know how applicable they are to the earth's field. For a review of these models, please see Merrill et al.'s book "The Magnetic Field of the Earth". Given that we know the Earth has a magnetic field and that the magnetic field reverses, questions 2-4 are meaningless. In science, we proceed along lines of enquiry that will bear fruit based on first-order observations. You can deny that magnetic reversals are real and you can deny that the earth has a magnetic field, but that won't produce much useful science. A better approach is to take the observations and ask "Hmm, how does one sustain a self-reversing magnetic such as the one we observe"? There are real questions about how we generate a self-reversing dynamo in the Earth and the focus should be on those questions.
Cheers
Joe Meert
This message has been edited by Joe Meert, 01-28-2005 13:28 AM

This message is a reply to:
 Message 192 by Hydroplate Hippie, posted 01-28-2005 4:11 AM Hydroplate Hippie has replied

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Quetzal
Member (Idle past 5872 days)
Posts: 3228
Joined: 01-09-2002


Message 199 of 234 (181427)
01-28-2005 4:42 PM
Reply to: Message 197 by Jazzns
01-28-2005 12:01 PM


Re: Geo 101 Plate Tectonics vs Hydroplate
3) Biogeography
Particularly marsupial biogeography. Extant and fossil marsupials have only existed in certain geographic environments. In particular, as you extrapolate through geologic time, the ancestors to current day marsupials were exclusively located in South Africa, Antarctica, Australia and South America. As species were geographically separated due to plate tectonics, marsupial species diverged in their respective isolated areas. Assuming that a proto-marsupial "kind" cannot "micro evolve" into a kangaroo in a weekend, this process was slow.
It's a bit more complicated, but you have the gist. The earliest major radiation of marsupials post-dates the breakup of Gondwanaland when what later became Australia, Antarctica and South America were joined. Interestingly, the earliest metatherian fossils (Late Cretaceous) are from North America AND South America. All N. American marsupials went extinct during the Miocene. It looks now that marsupials went from S. America to Australia via Antarctica, and possibly from N. America to Asia. Weird, hunh? Mesosaur fossils found in South America and Africa also show these two continents were once joined, but not since about 125 Mya.
Also, someone please confirm this, I believe that marsupial migration into North America only became possible once North and South America became connected via Panama. Therefore we can time the diversification of marsupials into North America with the data from plate movement. The conclusion is that plate tectonics is a slow process.
Correct. The Great American Interchange took place approx. 3 mya. The only living N. American marsupial, Didelphus virginiensis, entered at that time from S. America. It also marks the end of the great metatherian radiation in S. America, possibly due to competition from placentals from the north.
Obviously the Antarctic populations went extinct when the continent arrived in the polar regions, leaving only Australia to carry on with the impressive evolution of marsupials.

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roxrkool
Member (Idle past 989 days)
Posts: 1497
From: Nevada
Joined: 03-23-2003


Message 200 of 234 (181541)
01-29-2005 1:41 AM
Reply to: Message 197 by Jazzns
01-28-2005 12:01 PM


Re: Geo 101 Plate Tectonics vs Hydroplate
Not only do mountain ranges match up from one continent to another, but so do fossil accumulations, stratigraphy, mineral deposits, hydrocarbon deposits, and probably a whole host of other things I'm forgetting. Additionally, the mountain ranges themselves are often evidence of previous tectonic continent-continent collisions.
As for the Rockies, the Rockies we see today are actually the youngest of at least one (possiby episodic) earlier episode of orogenic activity in the same vicinity. The Ancestral Rockies were uplifted and deformed and then eroded to almost a peneplain (from which the Maroon Bells and Pennsylvanian/Permian Fountain Fm. conglomeratic/clastic alluvial deposits were sourced and deposited into separate basins), and subsequently thrust up again into what we see today.
In some portions of the Rockies, you can still see some of the peneplain where it has been preserved. They stick out like sore thumbs as extensive flattened areas with low rolling hills surrounded by the rugged sharp peaks of the younger Rockies.
White Ranch Park Open Space (elevation ~7,000 ft.) is one such place (notice the foreground, not the mesas in the background) - unfortunately, I wasn't able to find a nice illustrative picture of the White Ranch area. Another preserved peneplain location is at Rocky Mountain National Park (elevation 12,000+ ft.).
Peneplanation of ancestral highlands was not limited to the east-central Rocky Mountains, but incorporated the entire range from north to south and east to west. We have many examples of eroded highlands and adjacent basins containing the eroded material (see: Continent-Continent Collision along the Southern North American Margin: The Ouachita-Marathon Orogeny for more info).
When you start digging into the geologic history of a continent, nevermind one little state, the amount of time required to form these various landscapes begins to take hold.
There are only two possible solutions to explain the complexities of the global geologic record, either 1) God created the world to appear old, in which case no evidence is possible or necessary, or 2) the Earth IS old, in which case we have ample evidence to support such a position.

This message is a reply to:
 Message 197 by Jazzns, posted 01-28-2005 12:01 PM Jazzns has replied

Replies to this message:
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Jazzns
Member (Idle past 3911 days)
Posts: 2657
From: A Better America
Joined: 07-23-2004


Message 201 of 234 (181671)
01-29-2005 1:48 PM
Reply to: Message 200 by roxrkool
01-29-2005 1:41 AM


Re: Geo 101 Plate Tectonics vs Hydroplate
Awesome info! Thanks to you and Quetzal.
I think the big idea I was trying to get at for the purposes of this thread is that any hypothesis that proposes some kind of faster plate tectonics must also account for the evidence from numerous other fields of science that support the continents moving slowly. It really is a mountain of a problem it seems for anyone to undertake.
The reason the Hydroplate nonsense hasn't been subject to scrutiny is IMO that its creators are not stupid and do actually know about the hordes of other evidence that have the plate moving slowly. Therefore it is more of a political action of trying to garnder support from the layman for their crusade to push religion into public education.
To many people are misled by heroic drama to realize that one scientific sounding "breakthrough" is not enough to overturn paradigms that are cemented for all practical purposes. How long did it take the works of even those we condisider legitimate geniuses to take foothold in the scientific knowledge of society?
When you see it for what it is, it becomes a lie. A purposeful lie which is in discrete travesty to Christian values. For all the effort that concerned citizens, scientists, and educators put into dispelling the efforts of these tricksters I think that the biggest outrage needs to start to come from within Christianity for the lies being peddled to innocent people in the name of the Lord.
Sorry for the slightly off topic rant. Please take further digressions into a seperate thread.

Now is the winter of your discontent!
-- Stewie Griffin

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gengar
Inactive Member


Message 202 of 234 (181779)
01-30-2005 4:33 AM
Reply to: Message 180 by Hydroplate Hippie
01-28-2005 1:53 AM


Convection and the geodynamo
Hi Hippie,
Thanks for your posts. You write a lot, and I think some of your points are possibly getting lost in the sheer volume, though. So I’m going to cut it down a bit, and try and concentrate on the most basic points first. I’ll address the geodynamo stuff in this post, and then I’ll do another about the sea floor stripes.
Regarding my last post you write:
So I think the best we can do here is to - agree to disagree and - move on.
I’m not sure why we should do that. You were arguing about uncertainty in the parameters. I agree. But my post demonstrates that even with this uncertainly, we can still be certain that the outer core convects. Or do you dispute that a system with a Rayleigh number of at least 1E16 will convect?
The critical Rayleigh number is an experimental observation — systems where it is >1000-2000, convect. Always. So when you ask,
On what basis do you know that the mantle convects?
My answer is again, ‘because the Rayleigh number of the system is much greater than 1000’. However, we can also map temperature anomalies in the mantle by looking at small variations in the speed of seismic waves (colder = faster, hotter = slower) which directly show us features indicating convection - particularly the cold downgoing slabs at subduction zones:
Indeed, earlier in the LDEO webpage you quoted, it quite clearly states:
it is reasonable to ask whether the Earth's interior, given what we have inferred about it in various ways from analysis of external measurements, can convect heat and hence experience convective motion. The answer is yes.
But I’m glad that we’re finally clear that mantle and core convection are separate. Perhaps further discussion of your quote about plate tectonics and mantle convection should take place in another thread. I’d be happy to participate of course; it’s a very interesting topic.
OK, back to the magnetic field. You gave a good explanation of lightning; however, as you yourself acknowledge it’s not really relevant in this case. In the inner core, we’re talking about a manifestation of the dynamo effect. The convection currents move a conductor, iron, in magnetic field, generating a current, according to the left hand rule we all learn in school:
This effect will apply in the core just as much as it does in the generator at your local power station.
At this stage, I’d like to stop and ask you some simple questions to see where we’re at. Do you agree or disagree with the following points?
  • Convection will occur at Rayleigh numbers of greater than 1-2000.
  • The outer core, even given our uncertainty over certain parameters, has a Rayleigh number which is much higher than 1-2000.
  • A moving conductor in a magnetic field will generate a current.
I’ll wait for your answers on these before moving on.
I’d also like to clarify that this desire to do away with reversals is to do with your clear preference that the magnetic field is a property of the inner core? You obviously couldn’t have reversals if it was. However, when you say:
The solid inner core (with permanent magnet properties) is logically the primary generator of the geomagnetic field
you’re forgetting that iron loses its ferromagnetic properties above about 700 degrees Celsius — the inner core is much hotter than this, so will not act as a permanent magnet. Thus your hypothesis suffers from the fate you ascribe to geodynamo theory — it violates known physical law.
You also say
Data that seems to indicate a geomagnetic reversal must have alternative explanations (just as Ptolemy’s data did).
Yes, but whilst Ptolemy was wrong in thinking the planets moved around the Earth, the planets still move. Geodynamo theory may be wrong, but REVERSALS STILL HAPPEN.
Anyway, I’m glad you’re finding this discussion informative. As, you suspect, I’m a real ale man, although my friends in Phoenix will attest that I’ll drink anything at a pinch
I’ll get to addressing the sea floor anomaly stuff now

This message is a reply to:
 Message 180 by Hydroplate Hippie, posted 01-28-2005 1:53 AM Hydroplate Hippie has replied

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gengar
Inactive Member


Message 203 of 234 (182808)
02-03-2005 9:20 AM
Reply to: Message 189 by Hydroplate Hippie
01-28-2005 3:12 AM


Re: Marine magnetic anomalies
So, on to the magnetic anomalies. This is as good a place to start as any:
Hippie writes:
Having worked on a drilling rig, this is one question I had. I may be slow here but wouldn’t the field (north) always point down at some angle?
That depends on where you are on the Earth. Here’s a simple representation of the present day field:
As you can see, the field does indeed point down in the northern hemisphere; but, in the southern hemisphere, it points up. However, we find a great many rocks in the northern hemisphere with a magnetization that points upwards, in the opposite direction that we’d expect; and crucially, rocks in the southern hemisphere of a corresponding age have magnetizations that point downwards. This is what tells us that at certain points in the past, the Earth’s magnetic field was reversed — the flux lines were all pointing in the opposite direction, as we see in the image below.
Hippie writes:
Deviation implies measurements above or below the reference field. Do you know if the reference field is relatively stable in circumferential measurements the same distance on Earth’s surface relative to the North magnetic pole?

Also do you know how the global reference is determined? Is it an average of circumferential readings at a given distance from present true magnetic north is it an average of a given latitude or is it an average of some defined area?
There is actually significant variation in the reference field at all latitudes; it is not a simple beast. Did you go to the link I gave to the International Geomagnetic Reference Field?. As they say:
The International Geomagnetic Reference Field (IGRF) model is the empirical representation of the Earth's magnetic field recommended for scientific use by a special Working Group of the International Association of Geomagnetism and Aeronomy (IAGA). The IGRF model represents the main (core) field without external sources. The model employs the usual spherical harmonics expansion of the scalar potential in geocentric coordinates. The IGRF model coefficients are based on all available data sources including geomagnetic measurements from observatories, ships, aircrafts and satellites.
The figures above aren’t a completely accurate representation of the field. Although the earth’s magnetic field is dominantly dipolar, there are also quadrapole and even octopole components (in other words, there do exist other, weaker, magnetic poles, it’s just that compasses respond most strongly to the largest one). Secular variation is caused by the change over time of the strength of these different components. The IGRF takes all our current measurements of field direction and intensity, all around the globe (satellite measurements are a major source nowadays) and then calculates the field which best fits all these measurements. Have a look here if you want to see maps of this field.
This gives us an accurate (as it includes many measurements distributed over the whole planet) representation of the field being generated inside the Earth (however you want to say it is being generated). What it does not account for is for local sources of magnetism. If you are measuring the magnetic field and happen to be standing over, for example, a large mass of iron ore, the presence of a large mass of magnetic material is clearly going to have an effect on your reading — you will see a deviation away from the reference value. However, whilst it will have a very large influence on your reading when you are directly over it, the effect will reduce very quickly as you move away from it, becoming insignificant when you get more than a few km away.
This is what it meant by a magnetic anomaly — an additional component in the locally measured field, which has a short wavelength — it can only be detected over a small area.
When we measure the field over the ocean floor, we see such short wavelength anomalies — positive and negative deviations from the average field. These are the magnetic stripes. Such anomalies must have a shallow source (if they were deeper, they would be ‘smeared out’ over longer wavelengths), which is why we know they are due to the magnetization of the oceanic crust. And, just by considering the principles of superposition, we can work out the polarities of these magnetizations. In the northern hemisphere (field currently points down):
  • A section of ocean floor with a normal (downward pointing) magnetization adds to, and will increase, the local magnetic field.
  • A section of ocean floor with a reversed (upward pointing) magnetization subtracts from, and will decrease, the local magnetic field.
I think I’ll stop here. We can address any questions you have about the above before we move on.

This message is a reply to:
 Message 189 by Hydroplate Hippie, posted 01-28-2005 3:12 AM Hydroplate Hippie has replied

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Hydroplate Hippie
Inactive Member


Message 204 of 234 (183394)
02-06-2005 1:29 AM
Reply to: Message 203 by gengar
02-03-2005 9:20 AM


Re: Marine magnetic anomalies
Hello Gengar,
Just a note to thank you for the posts. You do well to focus on the issues at hand. I have five lives outside this forum and one of them is coaching a 7th grade basketball team for fun - two practices and three games this week (undefeated I might add)!
So please bear with me as I like to give your posts the consideration they deserve and respond thoughtfully.
Best to you,
Hippie

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Hydroplate Hippie
Inactive Member


Message 205 of 234 (185735)
02-16-2005 1:11 AM
Reply to: Message 202 by gengar
01-30-2005 4:33 AM


Re: Convection and the geodynamo
Once again, a most excellent analysis Gengar! Your responses make this exchange worth the time. Thanks again.
Gengar writes:
You write a lot, and I think some of your points are possibly getting lost in the sheer volume, though.
Yes, it is obvious that most participants are either not reading or ignoring the central issues raised here. Other folks on this forum seem to relish a self-appointed intellectual superiority and seem interested more in trashing folks than in exchanging knowledge and information. I much prefer a straight-up technical discussion such as you provide. If not for your posts, I probably would have left this forum already.
Gengar writes:
However, we can also map temperature anomalies in the mantle by looking at small variations in the speed of seismic waves (colder = faster, hotter = slower) which directly show us features indicating convection - particularly the cold downgoing slabs at subduction zones: (Post 202 Farallon Slab illustration)
Variations in speed of seismic waves may be viewed differently (denser=faster, less dense =slower). It may not be valid to assume seismic speeds as a function of temperature alone.
Certainly compression can be a factor. If compression is the root cause of the faster seismic measurements, then the compression event presented in the Hydroplate theory is a reasonable alternative interpretation of density (versus slab subduction). In my opinion, the inferred shallow subduction angle (almost horizontal to Colorado) attributed by some (Carleton College: File Not Found) to the proposed Farallon slab subduction - is better explained by compression generated by western motion (and settling) of the North American Plate. I don’t perceive any reasonable mechanisms for proposed nearly horizontal plate subduction so far inland.
But then the proposed mechanism for subduction in general has been heavily debated within the geological community in recent years (push, pull, convey, drop).
Low gravitational anomalies over oceanic trenches evidently surprised some folks since older traditional plate tectonic theory proposed plates being shoved into subduction.
Gengar writes:
Indeed, earlier in the LDEO webpage you quoted, it quite clearly states:
it is reasonable to ask whether the Earth's interior, given what we have inferred about it in various ways from analysis of external measurements, can convect heat and hence experience convective motion. The answer is yes.
You are correct Gengar. That is why I qualified the reference to LDEO in post 180 on page 12 with the statement: Although they have not yet discounted mantle flow.
The inferred yes conclusion is required - short of abandoning plate tectonics theory (as we know it). It has not been directly observed, measured, or confirmed.
My reason for the quote was to point out that the plate tectonics theory is undergoing some significant revision to the point that some Lamont-Doherty Earth Observatory researchers are disputing standard textbook geology. In addition:
Even so, the model of the plates being dragged by the flow of the underlying mantle now appears too simplified. Most geologists now believe that the connection between the soft asthenosphere and the lithosphere above it is not sufficiently strong to allow this dragging motion. Although mantle convection is probably involved in some way, other forces must contribute to plate movement
Although the relative contributions of these different forces - mantle convection, ridge-push, slab-pull, and gravity-sliding - have not been quantified as of yet, it is most likely that they contribute differently to the motions of different plates. This topic will continue to be an area of research for some time to come.
http://facstaff.bloomu.edu/lhtann/Lecture4.htm
I believe there are significant implications from the reference above. Anyone who thinks the Plate Tectonics theory is "rock solid" aren't paying attention in my opinion.
Gengar writes:
You gave a good explanation of lightning; however, as you yourself acknowledge it’s not really relevant in this case. In the inner core, we’re talking about a manifestation of the dynamo effect. The convection currents move a conductor, iron, in magnetic field, generating a current, according to the left hand rule we all learn in school: (post 202 left hand rule illustration)
Gengar, I never stated the lightning analogy in post 180 on page 12 was not really relevant. I will repeat my statements here in part for clarity:
Hydroplate Hippie writes:
This (Sustained electric current in proposed geodynamo) might be possible if the Earth interior were a perfect superconductor, but it isn’t.
The reason a geodynamo could not possibly power the geomagnetic field is the speed at which electrical current flows and dissipates into heat (this is why I stressed the relative speeds of proposed convection currents and electrical currents in the previous post).
Let me make a loose analogy with a lightning strike to ground — it is not a perfect analogy since the atmosphere is a different type of conducting medium - but the concept is similar.
The electrical current continues to flow until the voltage potential is essentially the same between the cloud and the ground. At that point the current flow stops and the electromagnet field immediately collapses to zero
The problem is the voltage differential is quickly equalized and all the current is dissipated to heat — almost as fast as the flash of a camera
The electromagnetic field will completely disappear until another large voltage is built and creates another current path
And electrical current flows so fast that it is like taking a snapshot of the proposed convection currents — they are essentially static in motion during the instant of electrical current dissipation into heat.
In microseconds, all the voltage potential differences in the core would be equalized and the current flow would stop — collapsing the electromagnetic field to zero. This analogy does not address the additional problems:
Just as in a lightning strike, proposed voltage differential in the entire core would be neutralized, current flow stops, and the field collapses — all in microseconds.
Any motion in a proposed outer core convection current — even in a highly conductive medium - will not regenerate or sustain the voltage potential difference, electrical current, or electromagnetic field.
This is one of several reasons no one has proposed a plausible mechanism for geodynamo controlled geomagnetic fields.
Evidently, when the geological community embraced Hess’ geopoetry as clear evidence of geomagnetic field reversals and seafloor spreading — they had not thought through how this relates to physical laws.
Now, we are faced with a paradigm inferred largely from a hypothesis (magnetic striping caused by geomagnetic pole reversals) with no reasonable solution. It fails the test of science.
Gengar writes:
This effect will apply in the core just as much as it does in the generator at your local power station.
The core and our local power station are not similar. The core, consisting largely of solid and liquid iron, would be one massive instantaneous short circuit.
All the electrical energy would be dissipated as heat in the blink of an eye - just like a lightning strike.
The generators at our local power station would also convert all of their energy into heat, burn up all the components, and cease to conduct electrical current in a short circuit condition (if fuses or breakers didn’t quickly open the circuit).
Gengar writes:
At this stage, I’d like to stop and ask you some simple questions to see where we’re at. Do you agree or disagree with the following points?
  • Convection will occur at Rayleigh numbers of greater than 1-2000.
  • The outer core, even given our uncertainty over certain parameters, has a Rayleigh number which is much higher than 1-2000.
  • A moving conductor in a magnetic field will generate a current.
Gengar, you have the best approach on this forum.
  • Generally agree with the Rayleigh convection. However, the critical number is a function of geometry and the assumptions of incompressibility and uniform gravitational force. http://engr.smu.edu/~arunn/html/convect/rbconvect/rbcon.html
  • With respect for your diligence and persistence, I am doing some more detailed review on the assumptions and parameters in your calculations. Need more time there.
  • Agree on inductive current (use it all the time).
Gengar writes:
I’d also like to clarify that this desire to do away with reversals is to do with your clear preference that the magnetic field is a property of the inner core? You obviously couldn’t have reversals if it was. However, when you say:
Hydroplate Hippie writes:
The solid inner core (with permanent magnet properties) is logically the primary generator of the geomagnetic field.
you’re forgetting that iron loses its ferromagnetic properties above about 700 degrees Celsius — the inner core is much hotter than this, so will not act as a permanent magnet. Thus your hypothesis suffers from the fate you ascribe to geodynamo theory — it violates known physical law.
That is an excellent point Gengar but one that I didn’t forget. I examined the mechanisms in detail relative to all paradigms and possibilities for the geomagnetic field.
But first, the magnetic field as a property of the inner core is not a function of my clear preference or desire to do away with reversals.
Sound science is my preference — regardless of whatever philosophy or paradigm it may support.
The inner core configuration is the only feasible configuration that works to produce the geomagnetic field we observe - within the constraints of physical laws — that I have been able to determine.
The geomagnetic field having a different axis from the crust rotation axis is one of several unexplained phenomena that I had puzzled over for many years. When I stumbled on the Hydroplate theory in an unrelated Google search, it presented the first rational explanation I had seen. Still, I welcome proposed alternative mechanisms.
Since you have questioned the viability of this configuration, I will briefly sketch the proposed working hypothesis. You will need to study additional details yourself if you are interested.
It requires a reconsideration of some assumptions many folks currently infer as "known" within the Plate Tectonics paradigm.
The currently favored view for Earth evolution is that Earth was once a molten liquid mass. If that were true, the heavier metals should have sunk deep toward the core. A ton of uranium equals roughly a ball only a foot in diameter at Earth’s surface (someone check my memory here please - anyway, it's dense!). We should not find thick veins of heavier metals such as gold in the Rocky mountains — not even geologically associated with volcanic activity. (Some may say with enough time - anything is possible but that is a stretch, in my opinion).
British geologist Arthur Holmes (1890 — 1965), hypothesized that heat generated in the Earth by radioactive decay might cause convection of rocks in the mantle. Radiogenic material is inferred in the core to provide a heat source for convection currents and proposed geodynamo generated electrical currents responsible for the geomagnetic field.
Incidentally, I read one interesting paper from an Austrailian geophysicist who asserted global warming was preventing adequate cooling of the radioactive core and that the core may reach critical mass and blow Earth to bits. (So I may have to give up smoking cigars.)
Seriously (again), as I have asserted in this forum, there is no mechanism that has been proposed that would produce the geomagnetic field from a dynamo. Therefore, the possibility (IMO - likelihood) exists that inferred radiogenic material is not much more bountiful in the interior of the Earth (on average) than we find on the surface. If that is true, then there is likely an alternative source for the heat in Earth’s interior.
The proposed mechanism is friction heat from shifting mass under high pressure. If we scrape a single brick on end across an inch of concrete on the sidewalk, we generate some heat and the sidewalk is slightly warmed. However, if we were able to stack a column of bricks many miles high and scrape it an inch on the sidewalk — the concrete is burned or melted by the friction heat.
As we have agreed in this thread, the pressure at the center of Earth’s core is approximately zero — mass is pulled outward in all directions. Therefore, if the innermost core is not a stockpile of radiogenic material, it will not be inherently hot.
As we move outward toward the mantle, the pressure increases significantly and we would expect more heat due to pressure. Consider the map here and analyze certain features in light of the following text:
The Hydroplate theory proposes that mass shifted through the Earth from the Western Pacific toward the rising (ballooning outward) Atlantic floor.
If we consider the horizontal axis of the map to be 360 degrees, then we can visualize various features at relative 180 degrees apart. This shifting of mass would have required tremendous forces and would have resulted in friction heat melting material in the core.
Segments of metals with higher melting points would have sunk toward the center to form a solid core. Depending on the pattern of movement (along paths of least resistance), it is conceivable that relatively large segments sunk inward.
Proposed magnetized heavier components would not have melted and would have at least partially aligned with other core components magnetically while settling into the core.
As the heavier metals converged downward to the inner core, conservation of momentum resulted in a faster core spin (of which we now have evidence). I believe the Curie point would be higher since metals have a higher melting point under pressure - increasing radially outward through the inner core.
Although the reference below adheres to the hot radiogenic core paradigm, the concept of core cooling may be valid just the same. If that is not the case, then we can only assume the inner core has not reached melt temperature for its constituent components.
Cooling of the core has proceeded from the centre outward, and as the temperature has dropped below the melting temperature of the metals in the core, so the core has solidified (essentially, frozen) into a solid, starting from the centre.
As cooling has proceeded so the solid inner core has grown at the expense of the liquid outer core throughout geological time. This growth proceeds along the boundary between the inner and outer core where the iron/nickel liquid of the outer core solidifies and accretes to the inner core.
David Scarboro, Faculty, Earth Sciences, The Open University
http://www.madsci.org/...chives/oct2001/1002908647.Es.r.html
Notice in the map above the appearance that the entire Western Pacific has been collapsed downward.
The Ring of Fire around the Pacific denotes where the primary faulting has occurred in arcs and cusps as would be expected if the entire plate is pulled down.
The Hydroplate theory has stated for many years that gravitation and rotational balancing forces continue to slowly drive mass through the Earth's interior toward the bulging Atlantic from the sunken western Pacific (especially the deep trenches) on the opposite side of the Earth.
We also see an anomalous gravitational deficiency around the trenches as we would expect with a downward pull. Now view the actual GPS data that has since been made available:

Click for enlarged image
We see with few exceptions, almost all mass moving toward the Western Pacific to achieve balance in agreement with the Hydroplate Theory.
Even with the few exceptions, notice whether the anomalous direction of movement is toward a depressed area and whether some causation may be roughly 180 degrees away on the map.
How many predictions from the Plate Tectonics theory were at odds with the data we now see here? Perhaps Joe Meert could answer that for us (predictions before such wide scale data was available).
Consider again the first map in this post. According to the Hydroplate theory, the fairly rapid compression event thickened and crushed plates, creating mountain ranges. This rapid compression resulted in the most massive surface imbalance at the Himalayan Mountains and the Tibetan Plateau in the Northern Hemisphere.
This centrifugal imbalance caused the crust of the Earth to roll the Himalayan range toward the rotational axis equator. As this roll occurred, the stress in the crust (as it moved relatively quickly and stretched through the equatorial centrifugal buldge) during the roll produced the rupture or suture known as the "90 East Ridge".
The southern part of the 90 East ridge indicates the approximate location of the previous equator and the unusual "fairly straight line" of the ridge points to the Himalayan range and plateau as the prime mover. The linear direction of the roll (toward the equator to achieve better inertial balance) is marked as a result of the centrifugal forces rolling the crust after the mountain range was pushed upward. Very few (relatively) straight lines occur in nature. What is the Plate Tectonics explanation for the "90 East Ridge"?
This proposed roll did not affect the core and this is why the crust rotational axis and the core rotational axis are different today.
Granted, this configuration is not likely to have existed and sustained a geomagnetic field for billions of years (due to friction losses). However, the known decrease in current field strength is expected with this configuration.
Gengar, the Hydroplate theory presents the ONLY rational configuration I have found to explain geomagnetism observations today. If that were not the case, I would probably have ignored it. However, it breaks currently held paradigms. In my opinion, any valid criticism should include an alternative configuration for the geomagnetic field - with well understood mechanisms.
If there is another configuration with reasonable mechanisms, I am very anxious to hear about it!
Otherwise, the Plate Tectonics paradigm is no better and (at least with respect to mechanisms) not as strong - in my view.
Gengar writes:
Geodynamo theory may be wrong, but REVERSALS STILL HAPPEN Anyway, I’m glad you’re finding this discussion informative. As, you suspect, I’m a real ale man, although my friends in Phoenix will attest that I’ll drink anything at a pinch
Yes, very informative!
Unfortunately, I’m just stubborn enough to require a feasible mechanism before I can embrace the possibility of geomagnetic reversals. As an engineer, I’ve been burned too many times with assumptions.
As I said, your thoughtful posts make the time here worthwhile and thanks again!
{Big Grin} If you ever get around the Ozarks, you are welcome to visit and stay a while! Would enjoy meeting you.
You name the ale and the entertainment — on me!
Hydroplate Hippie
This message has been edited by Admin, 02-16-2005 14:35 AM

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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 206 of 234 (185802)
02-16-2005 9:20 AM
Reply to: Message 205 by Hydroplate Hippie
02-16-2005 1:11 AM


Re: Convection and the geodynamo
quote:
My reason for the quote was to point out that the plate tectonics theory is undergoing some significant revision to the point that some Lamont-Doherty Earth Observatory researchers are disputing standard textbook geology. In addition:
Even so, the model of the plates being dragged by the flow of the underlying mantle now appears too simplified. Most geologists now believe that the connection between the soft asthenosphere and the lithosphere above it is not sufficiently strong to allow this dragging motion. Although mantle convection is probably involved in some way, other forces must contribute to plate movement
Although the relative contributions of these different forces - mantle convection, ridge-push, slab-pull, and gravity-sliding - have not been quantified as of yet, it is most likely that they contribute differently to the motions of different plates. This topic will continue to be an area of research for some time to come.
http://facstaff.bloomu.edu/lhtann/Lecture4.htm
I believe there are significant implications from the reference above. Anyone who thinks the Plate Tectonics theory is "rock solid" aren't paying attention in my opinion.
Two problems with your analysis. First, your quote could have been one of mine from up to 20+ years ago. All of these mechanisms have been known for even longer than that and their degree of involvement has never been quantified. Simply enumerating them does not signify to me any major shift in geological thinking. Perhaps to you (and perhaps to students attending this lecture) this is all news, but I assure you that it is not to the geological community.
Second, you will notice that all of these mechanisms are natural, to some degree viable, and in no way support CPT over conventional plate tectonics. We frequently debate mechanisms for geological procesess without throwing out the basic concept of a theory. The fact that the lithospheric plates have moved is an inescapable fact. Exactly how they did so may not be nailed down, but we do have several possible and supportable mechanisms, which is more than Walt Brown has.

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edge
Member (Idle past 1706 days)
Posts: 4696
From: Colorado, USA
Joined: 01-09-2002


Message 207 of 234 (185804)
02-16-2005 9:35 AM
Reply to: Message 205 by Hydroplate Hippie
02-16-2005 1:11 AM


Re: Convection and the geodynamo
quote:
The Ring of Fire around the Pacific denotes where the primary faulting has occurred in arcs and cusps as would be expected if the entire plate is pulled down.
What plate? I see at least 5 plates in the Pacific Ocean.
quote:
The Hydroplate theory has stated for many years that gravitation and rotational balancing forces continue to slowly drive mass through the Earth's interior toward the bulging Atlantic from the sunken western Pacific (especially the deep trenches) on the opposite side of the Earth.
How does mass go through the interior? Do you realize that the Pacific ridges are bulging, also? And the fringes are sinking in both oceans? Do you understand what happens at the mid-ocean ridges? Have you ever studied mainstream geology?

This message is a reply to:
 Message 205 by Hydroplate Hippie, posted 02-16-2005 1:11 AM Hydroplate Hippie has not replied

  
JonF
Member (Idle past 168 days)
Posts: 6174
Joined: 06-23-2003


Message 208 of 234 (185807)
02-16-2005 9:56 AM
Reply to: Message 205 by Hydroplate Hippie
02-16-2005 1:11 AM


Re: Convection and the geodynamo
Unfortunately, I’m just stubborn enough to require a feasible mechanism before I can embrace the possibility of geomagnetic reversals. As an engineer, I’ve been burned too many times with assumptions.
As another engineer, you're being burned by ignoring reality. Even if the mechanism for reversals is really pink fairies working magic, the evidence clearly shows that reversals have occurred. Lack of a mechnanism does not trump evidence.

This message is a reply to:
 Message 205 by Hydroplate Hippie, posted 02-16-2005 1:11 AM Hydroplate Hippie has not replied

  
Hydroplate Hippie
Inactive Member


Message 209 of 234 (185831)
02-16-2005 10:46 AM
Reply to: Message 194 by Joe Meert
01-28-2005 9:08 AM


Re: PTs do not work
Joe Meert writes:
Name two well-known geologists who embrace the hydroplate hypothesis (it cannot rightly be called a theory).
You already know of some who recognize fundamental problems with Plate Tectonics theory and adhere to alternatives such as expanding Earth.
Not sure how well known he is but here is a quote from one emeritus geology professor:
Classic uniformitarian geology has failed to solve a number of problems in geology. By contrast, using catastrophic basic assumptions, Dr. Brown has given scientists a way of addressing many problems that is philosophically sound and scientifically acceptable to objective thinkers. Never before have I encountered a more intellectually satisfying and respectable attack on a broad spectrum of geologic and biologic problems that are laid bare in this work.
Douglas A. Block, B.A., B.D., M.S, Ph.D., Professor of Geology and Earth Science, Emeritus
Rock Valley College
Rockford, IL.
You will likely meet more in the future.
Joe, a hypothesis requires a cause/effect relationship to be tested. You have failed to identify a plausible mechanism (cause) for a geodynamo to produce the proposed geomagnetic reversals (effect). Therefore, Hess’ geopoetry used to infer seafloor spreading does not pass the hypothesis test. We have not been able test - or even model - a mechanism. This discussion reveals that a mechanism has not even been properly identified or defined within the context of fundamental laws.
Joe Meert writes:
I think you need to get out a little more often because a number of proposals have been featured in the recent literature that explain continental motion via mechanisms other than plate tectonics.
Yes, I am aware of that Joe - but some of your geological companions on this forum don’t seem to be. The recent literature is likely motivated, at least in part, by the realization that supposed convection currents are not an adequate driving mechanism for continental movement. Attempts to model plates driven by mantle convection with realistic parameters have all failed. And what are the alternative driving mechanisms to plate tectonics (convection currents). gravity and centrifugal force. The Hydroplate theory has asserted that from the start.
Joe Meert writes:
Walt's ideas are completely grounded in the Noachian flood myth. He started with his interpretation of the bible and then force fit his biblical interpretation into hydroplates.
Are you proposing that any scientific hypothesis that may coincide with a particular philosophy must automatically be suppressed? That is absurd. All hypotheses are designed to test an idea or an assumption Joe. The scientific method, when properly applied to test a hypothesis, is oblivious to whether the hypothesis was inspired by atheistic philosophy, Jews, Muslims, or the Wizard of Oz! If a young evolutionist (such as Brown) working near the Rocky mountains becomes intrigued to investigate a mechanism that could submerge those mountains... (and possibly lend support to a religious myth) does that disqualify his ideas or make him evil? Let’s focus on the science at hand rather than philosophy Joe.
If you can demonstrate the Hydroplate theory is scientifically invalid — then knock yourself out Joe! If it is silly mythical stuff, then you should be able to nail it to the wall scientifically. My review of criticisms has failed to do that so far. It is best if we analyze feasible mechanisms and let the philosophers hash out the implications.

This message is a reply to:
 Message 194 by Joe Meert, posted 01-28-2005 9:08 AM Joe Meert has not replied

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Jazzns
Member (Idle past 3911 days)
Posts: 2657
From: A Better America
Joined: 07-23-2004


Message 210 of 234 (185843)
02-16-2005 11:35 AM
Reply to: Message 209 by Hydroplate Hippie
02-16-2005 10:46 AM


What about the other evidence?
What about the other evidence that supports the rate of plate tectonics? My post (Message 197) gives just a few but if any are correct then regardless of mechanism we DO KNOW that the plates have not moved orders of magnitude quicker in the past.
Playing semantics with the current lack of knowledge about how the plates move exactly does not invalidate the numerous other lines of inquiry that science has for slow geologic activity, plate tectonics being one of them.
Kindly do not ignore challenges to your position.
Thank you,

By the way, for a fun second-term drinking game, chug a beer every time you hear the phrase, "...contentious but futile protest vote by democrats." By the time Jeb Bush is elected president you will be so wasted you wont even notice the war in Syria.
-- Jon Stewart, The Daily Show

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