Posted on 07/10/2004 8:00:26 PM PDT by bondserv
Plate Tectonics Gets Squishy 07/09/2004
Two reports on plate tectonics this week make it seem less like “hard” science. Over 30 years ago, plate tectonics theory surprised many by going mainstream. In recent years, however, observations have complicated matters.
In the July 8 issue of Nature,1 Norman H. Sleep evaluates a paper in the same issue2 that tackles the problem of hotspots. Regarding “inadequacies in understanding the relative motions between plates,” he comments, “In case you think this has been sorted out to decimal places in the past 30 years, it hasn’t.” (For background, see 04/02/2004 and 11/04/2003 headlines.) Sleep praises the efforts of Steinbeck et al. to understand hotspots and fluid motions in the mantle, particularly how the Hawaiian chain could make a sudden turn. But he ends, “I expect that debate will continue on the relative fixity of hotspots, the rigidity of tectonic plates and mantle dynamics.”
The Himalayas have been another poster child of plate tectonics theory. Richard A. Kerr in the July 9 issue of Science3 discusses new satellite measurements around the Tibetan plateau that cast a popular theory into question. It has long been taught that Mt. Everest and its range were thrust up as India crashed into the Asian continent. New synthetic aperture radar measurements from the InSAR satellite show much slower movement along faults than expected – like 0 to 7mm per year instead of 30, in one instance, and a factor of 10 lower in another. Interference diagrams, on the other hand, show the entire region deforming. Instead of a rigid mass moving between faults “like a watermelon seed between two fingers,” the Tibetan plateau seems to act like a fluid, as if “India were colliding with a water bed.” Kerr remarks, “For almost 40 years, scientists have recognized that Earth’s ocean floors jostle and slide past one another like enormous rigid plates. But how well continents fit into this plate-tectonic scheme has been less clear. Now, satellite measurements of the Tibetan Plateau suggest that when continents go head-to-head in mountain building, they can behave more like unbaked pizzas.” Another scientist concluded from the new data, “Continental tectonics is not plate tectonics.” Rather than stand and fight, Kerr says, this part of the continent is trying to escape.
Now I’m getting hungry for pizza and watermelon. Geological fads are like panaceas that cure all the symptoms until the MRI arrives. Some unscrupulous theorists like Charles Lyell fudged data to make it fit their mental pictures of what they thought the world should look like.
When plate tectonics theory became popular in the 1960s, some holdouts complained it was being foisted on them like a new religion. For example, even as late as 1983, in a popular geology book sold in western National Park bookstores, geologist Donald L. Baars had asked whether the theory was “Geophysics or Metaphysics?”—The concept of the New Global Tectonics may be liked to a new religion; since hard facts are lacking, if one is not a “believer” one is considered an “atheist” with regard to the many theories and interpretations of the “clergy”—the oceanographers and geophysicists. Many of the concepts are plausible and exciting, and sometimes they fit the hard geologic facts. Many times, however, they are contradictory and totally incongruent with known geologic facts, at which time the facts are ignored. With enough “faith,” every known earth event is compatible with the religion, especially with respect to oceanography. On land, however, where outcrops and fossils abound, it is often extremely difficult to be a “follower.” The entire doctrine may in time be proven true, it may be completely disproven by geologists, or a compromise may be reached. I prefer to think the last possibility is likely. ... [He describes some examples of contradictions.]Undoubtedly, various fluids and solids are moving various whichaways down under our feet, at various speeds and in various directions, but as with many things in science, the phenomena are too complex to reduce to simple models. What explains one province may not explain another. A neat global diagram of rigid plates floating on convecting mantle currents makes a nice flannelgraph in Monday School, but what was the Historical Geophysics? We’ll have to wait and see what happens to this religion. The lesson is: don’t take the national park diagrams on blind faith.
It would require another book to argue fully the pros and cons of plate tectonics theory. It is obvious at this point that I have not been totally converted to the religion. That is a matter for individual preference. You are free to believe as you wish, but please, don’t send missionaries! (Emphasis added.)
—Donald L. Baars, The Colorado Plateau: A Geologic History (Univ. of New Mexico Press, 1972, 1983, pp. 217-218, p. 219).
Pingeology!
Plate tectonics: Hawaiian pizza with extra cheese and watermelon.
It can and often does undergo periodic changes . . . and even reversals.
I can't say I agree with it, but it's very interesting reading.
Ha!
When it comes to structural geology, I get lost after the first fold and fault.
It's Bush's fault!
Re 4
That's why it's "theory" instead of dogma or article of faith. It's meant to be challenged and modified or superceded. Often it's one ugly little observation that crashes a beautiful theory, but that's science for ya.
Yeah, it's important to never think we know these things absolutely, though a lot of scientists do. It's all subject to change.
How much of what we "know" is wrong?
Reminds me of how, when I was 12 years old and on vacation in Yellowstone, we came across the petrified forest of Speciman Ridge. The National Park Service marker informed us that more than 20 forests had grown and then petrified, in exactly the same spot, one upon another.
My father, with his 8th-grade education studied this for a bit, then turned and said to me, "Son, don't believe everything you hear from Harvard."
He was right, the PhD'ed paleontologists were wrong. I haven't forgotten the lesson: Don't be too impressed with titles or degrees. The argument has to make sense. If they can't explain it clearly and rationally, they are probably wrong.
Its easy to find flaws in a theory, it is much more difficult to propose a more viable theory.
Given the knowledge that was gained about the earth during the 60's, Plate Tectonics was certainly the best explanation to fit the data. Maybe new data is indicating something else is going on. And so it goes with science...
I was trained as a geologist with the Plate Tectonic theory, I don't remember anyone elevating it to the point of a religious belief. Those that questioned it were not considered "atheists". That sounds like language used by someone who has a chip on his shoulder about the Plate Tectonics theory...someone who is just a bit defensive.
Bad scientists. But you are correct, there are quite a few bad scientists. I have found geophysicists to be among the best scientists in this regard--the most humble about the state of what is modeled as the dynamics of Earth. And mindful of how much more is to be discovered.
What did happen there?
So... what was the correct answer?
Ping
I was schooled 5-10 years before you, not one word in my books concerning Plate Tectonics. We where taught about massive mountain building due "orogenies" and other larger
geological events as "revolutions". The simple days were terrific.
With all due respect to your father, he was wrong and the paleontogists were, and still are, right.
What dishonest person tried to tell you otherwise? Note: If you're relying on the folks at answersingenesis.org or other creationists, I regret to inform you that they are frequently dead wrong, especially when they attempt to "explain" why scientific discoveries don't actually contradict young-earth creationism.
For example, the answersingenesis.org page on this topic claims, among other whoppers:
Growing forests have definite soil and humus layers, with lots of rootlets as well as a thriving animal population. However, the petrified ‘forests’ lack all these.This is, to put it frankly, an out-and-out lie. As geologist Bill Birkeland makes clear (note: a paelosol is a fossilized soil layer):
Amidon (1997) illustrated a number of in place / non-transported / in situ stumps, somewith trunks, using photographs and line drawings. For example, pictures and line drawing of **rooted** trees buried in place can be found in the section on pages 63 to 83, which is titled "Palesol Analysis", on of his thesis.And:Also, as the section title implies, in addition to solid evidence of **Rooted** trees within the Gallatin part of the Yellowstone petrified forest, Amidon (1997) also provides solid proof of the fact that these stumps are rooted in well-developed paleosols. Amidon (1997) recognized these "fossil soils on the presence of well- developed soil horizons, well-developed soil structures on both microscope and megascopic scale, and demonstrated alteration of clay and other minerals that can be best explained by the long-term weathering of sediments within an active soil associated with a stable subaerial, terrestrially exposed surface." [...]
Rettallack (1981, 1985, 1997) has documented well-rooted trees associated with fossil soils (paleosols). In fact, Rettalack (1997) contains a beautiful picture of one of the upright ( polystrate ) tree trunks showing it well rooted in a well-developed fossil soil (paleosol). Although there are many transported stumps, which have broken roots, it is an utter falsehood, to claim that all of the tree trunks, specifically the upright trees, "have been broken off at their base and do not have proper root systems". The presence of transported stumps and trunks mixed with in situ trees is quite typical of volcanic lahars as was directly observed within the debris flow deposits produced by the eruption Mt. St. Helens and many other volcanoes. This was something that Dr. Coffin either overlooked because he was so fixated with Spirit Lake or simply chosse to ignore in his arguments. Modern deposits and polystrate trees at Mt. St Helens virtually identical to the trees and strata at Yellowstone Petrified Forests has been documented by Yamaguchi, D. K., and Hoblitt (1995), Yuretich, R. F. (1981, 1984), and others.
[...] All the cut and pasted text about the Yellowstone Petrified Forests shows is "Dr." Walker's remarkable lack of knowledge of inconvenient facts, i.e. numerous paleosols (fossil soils), rooted upright trees; the flimsy nature of Arct's signature correlations; the fact that Arct's couldn't correlate 19 of his 28 trees; that Arct's data actually shows 5 of the 9 correlated trees definitely died in separate years; and so forth, about the Yellowstone Petrified Forests. Also, Walker overlooks the fact that if these trees were buried in a lake, lahar deposits wouldn't enclose these trees. Instead, fine-grained lake deposits would enclose the upright ( polystrate ) trees within the Yellowstone Petrified Forests.
References cited:
Amidon, L. (1997) Paleoclimate study of Eocene fossil woods and associated Paleosols from the Gallatin Petrified Forest, Gallatin National Forest, SW Montana. unpublished Master's thesis. University of Montana. Missoula, MT 142 pp.
Retallack, G. J., 1981, Comment on 'Reinterpretation of Depositional Environment of the Yellowstone "Fossil Forests"'. Geology. vol. 9, no. 2, pp. 52-53.
Retallack, G. J., 1985, Laboratory Exercises in Paleopedology. University of Oregon, Eugene, Oregon.
Retallack, G. J., 1997, A Colour Guide to Paleosols. Chichester, United Kingdom
Yamaguchi, D. K., and Hoblitt, 1995.Tree-ring dating of pre-1980 volcanic flowage deposits at Mount St. Helens, Washington. Geological Society of America Bulletin, vol. 107, no. 9, pp. 1077-1093.
Yuretich, R. F., 1981, Comment on 'Reinterpretation of the Depositional Environment of the Yellowstone "Fossil Forests"' and 'Stumps Transported and Deposited Upright by Mount St. Helens Mud Flows'. Geology. vol. 9, no. 4, pp. 146.
Yuretich, R. F., 1984, Yellowstone Fossil Forests: New Evidence for Burial in Place. Geology. vol. 12, no. 3, pp. 159-162.
Such paleosols are discussed by Amidon (1997). For example, he stated:The Specimen Ridge layered forests were indeed grown in the manner the National Park Service marker said they were. There is overwhelming evidence supporting that manner of formation, and overwhelming evidence ruling out the AnswersInGenesis "alternative" version."Fossil tree V15 and associated palesol (Figure 26a) are located approximately 80 m stratigraphically above other units examined in detail. V15 consists predominately of an extensive root system penetrating a moderately well differentiated paleosol (Figure 26b). The uppermost exposed layer is an olive gray Bt horizon (B horizon with clay accumulate) consisting of a massive, well indurated siltstone. The Bt horizon is underlain by a Bq horizon (B horizon with quartz accumulate) consisting of a greenish gray blocky siltstone encased in a crystalline matrix which grades to a brown, granular fine sandstone. The lowermost C horizon exposed in this section is composed of slightly modified parent material. Strata associated with V15 are interpreted to be paleosol formed in situ as a result of prolonged weathering."Amidon (1997) also, reported the presence of clay formed by the weathering volcanic sediment associated with this paleosol.The fact of the matter is that Bt and Bq horizons form only by the weathering of loose sediment. It is impossible for the deposition of sediment to create a sequence of soil horizons, identifiable by their microscopic and megascopic characters, like those noted by Amidon (1997) and illustrated by Retallack (1985, 1997).
This is significant because the Gallatin petrified forests are not only identical to the Specimen Ridge petrified forests but have been by geological mapping to be shown to be part of the Lamar River Formation and are approximately the same age as the Specimen Ridge petrified forests. It is impossible to argue that they have different origins as they are identical in physical characteristics, stratigraphic position, and wood taphonomy. They occur a few miles north of the Specimen Ridge petrified forest.
Your father was wrong on this one, and the paleontologists are correct.
I haven't forgotten the lesson: Don't be too impressed with titles or degrees.
The lesson I draw is that when people with an anti-scientific agenda, or a defensive attitude about people with extensive educations, attack well-supported scientific results, my money's on the folks with "titles or degrees" in the relevant field.
The argument has to make sense. If they can't explain it clearly and rationally, they are probably wrong.
In general I agree with you, but the kicker is that there are plenty of folks who will continue to cling to what they want to believe, no matter how clearly and rationally evidence to the contrary is explained to them.
[gcruse:] So... what was the correct answer?
The folks who bore false witness to cookcounty would like their readers to conclude that Noah's flood did it. But the evidence (the real evidence, not what they falsely say about the evidence) says otherwise.
For the correct answer, see post #18.
It *still* is. Contrary to the propagandizing by the creationist authors at "Creation-Evolution Headlines", plate tectonics is alive and well and still supported by overwhelming evidence. All that recent discoveries have "changed" is estimates of how readily the plates can deform under stress at plate boundaries, which was more a matter of "ooh, interesting, we'll refine our computer models a bit" instead of "wow, what a complete surprise, this changes everything", as "CEH" wants to falsely imply.
Maybe new data is indicating something else is going on.
In this case, no it's not.
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