Elementary and High School texts describe the origin of lava as pictured below. The books present the origin of lava as the result of mantle plumes, where hot rocks move all the way from the molten earth’s core to the surface. The transport time is something on the order of 30 million years. Does that sound believable that a temperature differential could be sustained for that long? Some geophysicists have finally revolted and said the textbooks are wrong.
Many readers may not realize, that no one has drilled down very far at all. The deepest drilling has only been about 14 miles down. From the surface to the Earth’s core is almost 4000 miles. We have barely scratched the surface, and we really don’t know what’s down there. On the picture below, the deepest we’ve drilled could hardly even be seen on the picture!
The demise of the mantle plume hypothesis will improve the chances of various YEC geologies, particularly Walter Brown’s hydroplate theory. If lava flow and plate techtonics can be refuted, then there is room for YEC geology to succeed. Hydroplate theory ties current volcanic activity and lava flow to the mechanisms that caused the great flood. Plate techtonics have a passing relation to mantle plume theory, and thus the demise of plumes furthers the chances of Brown’s hydroplate theory prevailing over old Earth, plate techtonics.
Scientists are unable to abandon a paradigm simply because its empiric base has crumbled. Denial …then anger ….is evident, just as in other bereavements [acceptance usually comes with the next generation, after a period of bargaining (ad hoc adjustments, rationalisations ….,changes in the protective shield of auxiliary hypotheses…
According to philosophers of science a research program is progressing if it displays the power to anticipate and accommodate additional data . Otherwise the program is called degenerating. A sign of an impending crisis in a paradigm is the number of times the words anomaly, paradox, unexpected, dilemma, counterintuitive, not understood, and problem appear in papers defending a hypothesis, or the number of rationalizations and additional assumptions made for failed predictions.
in 2002 several hundred papers about them are listed by the Science Citation Index, so the subject is paying a lot of mortgages.
Are we talking about Darwinian evolution? Well, not quite, but we are talking about bad ideas that have crept into science textbooks for the last 30 years. The issue is the origin of lava and mantle plumes.
Here is an example of a theory that should have been torpedoed on basic thermodynamic principles long ago, but was allowed to persist. The idea is that lave orginates from the Earth’s core and takes 30 million years to migrate to the surface. 30 MILLION YEARS!!!! Bury a hot or ice cold brick in the ground and tell me how long do you think it will maintain a temperature differential. Not 30 million years, not even a 1000 years, maybe not even 1 year!
Plumes or no plumes, that is the question Scientists having hot debate over how islands are formed
For more than three decades, scientists have offered a charmingly simple explanation for the Hawaiian Islands. They say the islands formed millions of years ago as the Pacific plate — a huge, slowly moving chunk of Earth’s crust, washed over by the Pacific Ocean — moved over a rising column of super-hot rock from Earth’s innards. The rising plume melted just below the plate as it passed overhead, forming a line of volcanoes that rose above the waves.
The theory is appealing partly because it’s so simple. Many high-school science students have watched their teacher simulate the formation of the Hawaiian Islands by moving a sheet of plastic, which mimics the moving Pacific plate, over the hot flame of a Bunsen burner, which mimics the plume. Result: The plastic develops a chain of blisters — which mimic the Hawaiian Islands.
Quick acceptance in 1970s
Plume theory won quick acceptance in the 1970s, when it seemed to jibe perfectly with plate tectonics theory, the then-trendiest idea in Earth science. According to that now widely accepted theory, Earth’s crust is broken into crustal plates that move about steadily, like slabs of ice in an ice floe, but very slowly, at rates of millimeters to centimeters per year.
The coolest implication of plume theory is that plumes bring us scientific treasures from the center, or near center, of the Earth. Geoscientists can’t travel to the center of the Earth a la Jules Verne to recover its contents. Rather, they rely on plumes to push those inner-Earth treasures from the edge of Earth’s core through its overlying mantle to the surface, where they gush from volcanoes.
Geoscientists also invoke plumes to explain so-called swells where Earth’s crust bulges upward, like the surface of a piping-hot souffle. Such bulges surround many volcanic regions, such as Iceland and the Hawaiian Islands.
For these and other reasons, “if there were no plumes, it would be a great disappointment,” says geoscientist Donald J. DePaolo of UC Berkeley.
And that’s the rub, for now some experts are starting to question the whole plume hypothesis. A showdown may come late next summer, when geoscientists plan to hold what they call the great plume debate at a conference in Scotland. A sort of dress rehearsal for that debate was held last month in San Francisco, at the annual gathering of the American Geophysical Union.
The Smoking Gun September 16, 2003
Notes:
1. This is something I was perparing to post at Uncommon Descent some months back, but decided would have been too provacative since it argues for special creation. Bill Dembski, Denyse O’Leary, DaveScot, Patrick, and about half of the UD authors and admins accept Old Earth. Out of respect for them, I post this essay here. DaveScot was focused on issues related to exterior Global Warming, I’m focused on interior Global Warming (or cooling depending on how one looks at the issue).
Correct me if I am wrong but I don’t think hydroplate theory denies plate techtonics, it just ascribes different historical motions to the plates.
Hydroplate theory is a “plate” theory, but Brown has been critical of plate techtonics, thus, following his convention, I contrast hydroplate theory with plate techtonics.
Sal
Another interesting article that just came out relative to heat distribution in the crust and the formation of continents is this fascinating article which explains that most of North America “floats” over hot rocks in the crust. If the rocks were to cool most of North America would sink beneath the ocean. Denver, the mile high city, for example, would sink over 700 feet below sea level.
I know Baumgarden pictured mountains popping up out the crust after the flood like corks floating on water. When I visit the Seirras that is what they look like. This above article explains how heat can expand the crust and create a continent.
It would be an expensive empirical project, but I think one that would be very informative. If we could drill deep in several locations and place temperature probes, we might get a clue as to what’s going on. Maybe even improve on the imaging of the Earth (much like CAT scans).
My personal dream is to have an advanced Laser Drilling mechanism to dig, say 1000 miles into the Earth’s surface. I do not know if it is possible, but I think it’s worth a try.
We will answer all manner of questions this way!
Mantle plumes comprise only a fraction of lavas. Most continental volcanos near plate boundaries are the result of subducted oceanic crust, which, due to the entrainment of water, has supressed melting temperatures, and so melts and rises to form the coastal volcanoes (like Mt. St. Helens).
Drilling has very little to do with our knowledge of earth’s interior, but it has never been claimed to! Our knowledge of the deep interior comes from several sources: seismic tomography being the most precise, and able to pick up small variations in the deep mantle at the boundary with the core. Models of its compostion and structure are constrained as well by free-earth oscillation measurements, models of the earth’s magnetic field, wobbles in the orbit, and constraints on total mass and angular momentum. Even the rate of post-glacial glacial rebound is factored in.
Before you write off heat differentials maintained for millions of years, you have to do the thermodynamic calculations yourself. A 100 km blob of hot material takes orders of magnitude longer time to cool off than a brick. I don’t know what the numbers are off-hand, but the criticism here sounds pretty off-the-cuff. Add in a greater percentage of radioactive material and maybe the differntial is self-sustaining.
I’m not saying that the above theory for the “origin of lave” is not taught, but I never saw it through my years of geology and it geophysics in university and it looks to me a bit like a straw man.
Finally, I’ve never seen any desire to “hang onto old or outdated” theories in my years in geophysics. It has been a very exciting field to be as long as I’ve been involved, with a constant input of new ideas and theories (the reluctant acceptance of plate tectonics notwithstanding). Let mantle plumes live or die, I’m yet to see anything which makes a young-earth perspective more appealing or of better explanatory power (and believe me, I’ve always on the lookout for it), though I’m open to hear and respond to suggestions.
The American geology community rejected continental drift for half a century and then all of the sudden if you didn’t accept it you were crazy. It was a text book case of scientists hanging onto a dead theory past its expiration date. It could happen again.
Dr Cheesman,
Thank you for your input. You offered some considerations I was not aware of.
However regarding this:
The calculations were claimed in note 24: here.
But let me offer a back-of-the-envelope calculation that I used to informally convince myself my position was reasonable. Assuming the transport distance is 3,000 miles (4,828 km), that equates to 16 centi-meters of movement per year (roughly six inches).
For a plume with a well defined edge and a temperature differential of 500 degrees celcius, rock nearby will be warmed to that temperature within a year. In fact, it will warm cold rock within 16 centi-meters easily, and thus it’s upward velocity is not fast enough to compete with how quickly it warms surrounding rock. Thus, it is moving simply too slowly upward to counteract the effects of it warming surrounding rock (and thus cooling itself).
These considerations are intuitively evident by trying to place a hot brick in soil or even some insulating material. A substantial temperature differential will not be sustained for more than a month. What is disturbing is that peer-reviewed literature has no direct laboratory evidence whatsoever that hot piece of rock in contact with a cold piece of rock will sustain that differential for very long at all, especially at high pressures where heat conduction is enhanced.
This is like trying to put a big hot brick in soil and moving it along 6 inches a year, even if it were a big brick buried 100 feet down, by the time it emerges 200 years later to the top, the original heat can’t possibly have been sustained.
One might argue we are dealing with larger bodies than a brick, but let me offer my counter. Unless the brick was much much bigger and deeper than the distance it is trying to traverse, the size will not be able to overcome the slow ascent speed. The brick will cool before it reaches the top. Plumes are much smaller in size than the distances they try to traverse, thus, they will cool off given how slowly they rise for the considerations I gave. The only recourse is to make the plumes so huge and tall that one wonders if this is a plume model at all.
Plume models are driven by Rayleigh-Bernard convection models. But these models do not account for cooling of the plume! I’ve not seen any cooling analyses whatsoever, except maybe only those which might refute the existence of plumes.
If we are talking about radioactive heating via heavy elements (like Uranium), one would have to wonder why the heavy elments simply don’t sink back to the core of the Earth (since we are modelling the solid rock as a fluid after all). So on those grounds I discount long term radioactive heating. The converse is true of light radio active heating (if such a thing is possible). They would have floated up out of the plume.
For plumes to succeed they need to really move faster. One calculation (referenced already) suggests speeds 10,000 times faster would be needed. But I don’t think any fluid model of solid rock will permit such a fast ascent. In fact, the slow speed of ascent is already highly optimistic.
I tried with very limited success to assess the heat profiles of underground nuclear tests to estimate the speed of heat conduction underground. It seemed very substantial from what scant discussion there is available on the net. I was unfortunately unable to get hard numbers, but the impression I got was something of astonishment at how quickly underground heat was dissipated. It seems there was a strong presumption hot things underground could stay hot for a long time….
I may ask Dr. Brown if he’d be willing to publish his calculations. His specialty at MIT was thermodynamics, so his input would be informative, imho.
Funny this thread should come up, I just rented the Sci-Fi disaster flick “The Core” DVD last weekend. It is a pretty amusing movie if you can swallow the premise. Scientists have to tunnel to the center of the earth in order to restart the core of the earth spinning. It somehow stopped, destroying the earth’s electro magnetic shield and threatening all life. One cool thing is it stars academy award winning acrtress Hillary Swank when she was still a B-list actress. The other thing I liked about it is it highlighted some of the finely tuned qualities of the earth necessary to support life.
As normal with these issues, I went to the Wikipedia page on mantle plumes to see what the “state of the art” is:
http://en.wikipedia.org/wiki/Mantle_plume
Some interesting points: The theory of mantle plumes dates back to 1971. The article is careful to note the theoretical aspect of all this, but explains the issues involved quite clearly. Seismic tomography seems to indicate that, independent of the speed (if any) at which they may transport material, plume-like structures do indeed seem to exist in many of the inferred locations. There are competing theories which try to explain existing data with processes occuring solely in the upper mantle, but the article ends with the following note:
“The current debate has stimulated an increased interest in research to distinguish between these models. This debate is ongoing, but recent advances in seismic tomography have enhanced its spatial resolution in both the upper and lower mantle. This has led to new seismic tomographs that resolve anomalous features consistently within the upper mantle, and in places to the lower mantle (e.g., Montelli et al 2004). It is becoming diffifult to explain this data by processes in the uppermost mantle.”
Interesting I search Google Scholar for “mantle plume” with one or more of the words anomalous, anomaly, paradox, unexpected, dilemma, counterintuitive, and contradictory. I got 3,760 hits.
Just for kicks, I tried the same search on Google Scholar with “phylogeny” instead of “mantle plume” and I got 28,700 hits. Talk about a theory in crisis.
I was in touch with Dr. Brown today. He has indeed done calculations, but he does not feel his work is in a state that it could be published. However, he sent me some clips of the Marsh paper which has made it through peer-review. That would be a good starting point against plume theory.
I told Dr. Brown I tought the plume issue would be a good field of further exploration in more minute detail.
I would further add it would be a very legitmate topic for a peer-reviewed paper in current day journals (provided it doesn’t get shot down out of prejudice). If not, it would be good material for the journal we’ve been talking about informally.
Scince I expect there will be other topics of extreme interest that I’d want Dr. Brown’s participation on, I suggested that Walt not waste too much time on the plume project. Besides, given the current plume war, there could well be other minds weighing in on this soon. I think it is something we can keep an eye on in the meantime.
I look forward to the day he and I can collaborate on a project.
Salvador, I noticed the following sentence in your comment above: “a plume with a well defined edge”. I would completely agree with you if by well-defined you mean a few centimeters, but models I’m aware of have “boundaries” on the order of kilometers, not centimeters, just as earthquake “faults” are not always single crackes, but can be dispersed over a broad (even kilometers) zone, over which the movement is distributed. Of course the width of the zone greatly lowers the heat gradient and the heat loss. Since the material is not a solid, but more a viscous liquid, with the visocosity also dependent on the temperature, the “edge” of the plume would also undergo differential motion, lessening the overall friction and resistance to upward flow. Again, I have no calculations to offer, but the form of the model does make a big difference in predictions of flow rates, longevity and cooling.
Salvador: “My personal dream is to have an advanced Laser Drilling mechanism to dig, say 1000 miles into the Earth’s surface. I do not know if it is possible, but I think it’s worth a try.”
Alas, beyond a certain depth (even a few hundred meters) the unconfined hole walls would crumble into and fill the hole due to the imbalance of pressure, increasing with depth. This is why deep holes have to be cased. You also get water flowing in. Also why you need rock bolts in mining operations to prevent rock bursts.
Even if you could use a laser, the vaporized rock needs to go somewhere, which would be up the hole, and scatter and absorb the beam.
Off topic: Salvador: Why do all the posts clip off the first one-two letters on the left side? I’m using the latest version of Internet Explorer, and no other blogs I’ve looked at have this problem.
i have that problem too, and I was hoping I was the only one. Let me see what I can do.
Sal
Dr. Cheesman,
I put a temporary fix to the problem. Let me know how things look on your end.
Regarding lasers, I realize that encasements have to be in place to keep the hole open. I would presume a laser drill would need some sort of vacuuming action as well to sip out the debris. However, my understanding is that the problem with deep drilling is that the diamond tipped drill bits melt. Very expensive.
I don’t think the hole needs to be very wide at all.
I know it sounds like wishful thinking, but I really would like to have a better clue what is down there. I think we’ve been constantly surprised at the findings of extremely deep drilling holes.
Also, it would be good to put heat probes at various depths. We could measure heat evolution, etc.
In my exchange with Dr. Brown, I learned Dr. Marsh’s calculations suggest lava could not emerge from 100 km down, but rather a relatively shallow origin.
There seem to be rather intense disputes in the geophysical community regarding the origin of lava. The basic premise of crustal plate friction creating lava seems reasonable, but Brown believes the movement of large masses of land at shallower depths (say 10 km) is the cause of lava. The heat calculations may give a clue as to which answer is closer to the truth.
YEC aside, if a shallow origin of lava is the case, confirming this would be a major contribution to geophysical understanding.
regards,
Salvador
Howdy Sal. I’m curious why you linked to a 2005 article as “news.” Did mantle plumes die in the two years since that conference? (Your links go straight to the geological society home page). I’m guessing not.
Sal, if you contact me off-list I want to ask you a question about something you said on UD. I don’t know your direct email, and this is the closest I could get.
To Jehu: Anomalies are not a bad thing: they are what drives research.
H
In geological time, 2 years ago is pretty recent and it is news to many.
I will try to e-mail you.
Sal
Actually hermagoras, let me suggest we discuss your question in the YoungCosmso Rhetoric Forum here.
I have set up a place to discuss the Rhetoric of ID specifically because of the inspiration of John Angus Campbell and Thomas Woodward and my own fascination with rhetoric (lots of it in the ID debate).
I would presume your question was not too personal, so I’m glad to talk about it publicly if you are. If not let me know, and I’ll e-mail you, but I’d prefer the topic be open to the public.
If your question was about your banning or the goings on at UD, I have little to say. UD is not my weblog, and I’m only a guest there like most anyone else. I have limited influence. That said, I have a policy of avoiding comment privately or publicly on management descisions at UD, unless of course it’s someone whose participation I’ve grown to detest like my old nemesis, PvM. (By the way I like PvM personally, decent internet persona. I just can’t stand it when he’s jamming my threads.)
Salvador
I posted over there, thanks. The question was not personal — it was just “dated,” as it were — and so there was no clearly appropriate venue to pose it.
Please Note:
ATTENTION! YOUNG COSMOS HAS MOVED!
Salvador