Fun with Creationist Plate Tectonics
From Left2Right to Pharyngula to you and me: High-Speed Plate Tectonics and Young Earth Creationism. Yow! Before we indulge ourselves in pointless nitpicking, let us address one misconception that seems to have come up among even the reality-based participants in this discussion:
Whatever Wegener might have thought, Pangaea was not “primordial”. Before there was Pangaea (c. 250 million years ago) there was Rodinia (c. 1 billion years ago). Before that, there may or may not have been other supercontinents, Columbia or Pangaea: Episode I or what have you – it’s hard to tell when most of the evidence has been swallowed back into the mantle. But it’s generally accepted that the continents have been stuck together and pulled apart at least twice. Since Genesis only
allows for mentions one such event, it’s silly to claim that the modern story of multiple supercontinents was a Biblical hypothesis.*
But we shan’t let that ruin our fun with Do-While Jones, a hammer, and our trusty lumps of silly putty. Oh, no.
Mr. Jones begins with a basic introduction to plate tectonics, which is pretty much accurate. Possibly this is because he cribbed it from Schmidt and Harbert. When he is done being sad that geology textbooks use metaphors (which he calls “New Age”) as a pedagogical device, and fail to credit the not-at-all metaphorical Bible as the progenitor of all knowledge, we see some of his independent assessments of plate tectonics. They’re not awe-inspiring.
Also, “independent” means “pulled out of context from a freshman geology text”:
The three differences between modern theory of Plate Tectonics and the ancient theory of the division of land during the time of Peleg are (1) how it happened, (2) when it happened, and (3) how long it took to happen.
Come to think of it, there are really only two differences. The explanation of how it happened is basically the same for both theories. In the creationist theory, the land was divided by some mysterious forces that nobody can adequately explain scientifically. In the Plate Tectonic theory, the plates are moved by some mysterious forces that nobody can adequately explain scientifically. According to one college geology textbook,
Some geologists believe that plate-tectonic movements can be explained by convection in the upper mantle. Other geologists believe that convection occurs in the entire mantle. Thus convection in the mantle is indeed possible and prompts geologists to debate some key questions: Is convection an important process by which heat is transferred in the Earth? Is convection occurring now? Has it occurred any time in the past?
The college geology textbook he mentions is Press and Siever’s Understanding Earth, which we happen to have handy (though it’s the second edition, from 1998, not 1994). It was my first geology textbook ever – awwww! In my copy, the two ellipses in that quote cover a section-break and a full paragraph, and must be read upside-down and backwards for those sentences to occur in the order in which they are quoted. Here’s the quote in situ:
[… an analogy to Silly Putty, to explain how seemingly rigid rock can flow over long timescales.]… at conditions of high pressure and temperature, the mantle behaves as an extremely viscous fluid and “creeps” or flows. Thus, convection in the mantle is indeed possible and prompts geologists to debate some key questions: Is convection an important process by which heat is transferred within the Earth? Is convection occurring now? Has it occurred at any time in the past?
Effects of Convection It turns out that seafloor spreading and plate tectonics are direct evidence of convection at work. The rising hot matter under mid-ocean ridges builds new lithosphere, which cools as it spreads away; eventually, it sinks back into the mantle, where it is resorbed. This is convection; heat is carried from the interior to the surface by the motion of matter.
Some geologists believe that only the upper few hundred kilometers of the mantle are subject to the convection that drives plates, as in Figure 19.10. This would imply that the upper and lower mantles do not mix. Others think that the whole mantle is involved. […] Regardless of the specifics, geologists now believe that the movement of heat from the interior to the surface as the seafloor spreads is an important mechanism by which Earth has cooled over geologic time.
So maybe there were some changes between editions. But after we strip away disingenuous pull-quotes (why were they from the section on heat flow from the earth’s interior, and not the section on the driving mechanism of plate tectonics?) we see that in the creationist theory, the land is divided by some mysterious force that can never be adequately explained scientifically, while in plate tectonic theory the plates are moved by a not-so-mysterious force which we are understanding better and better every day. Which is basically the same thing as not understanding at all.
The real fun, though, comes when we examine Mr. Jones’s central claim, that plate tectonics happened really really fast. Now’s the time to bring out the Silly Putty and the hammer! Take a lump of Silly Putty and whack it real good with a hammer – if you do it right, the normally pliable putty will shatter. This is the funnest illustration EVAR of the way materials respond very differently to forces applied at short time scales than they do to force applied steadily over time.**
When you’re done playing, take a look at these fabulous folded limestone beds in Pennsylvania and the Palmdale road cut. Try to duplicate those shapes by hitting your silly putty with a hammer (we know you weren’t really done playing).
We could go on to make snarky remarks about the way Do-While Jones confuses the Pacific and Farallon plates. But it’s Valentines Day and we have chocolate chips to melt into a lazy person’s fondue. Young-earther fish will still be in their barrels for shooting another day.
* Compatible with Genesis? Plausibly, if you’re willing to play fast and loose with the timescale. Predicted by it? Not so much.
**A less fun illustration occurs in woodworking: when you’re bending wood, you need to use steady pressure and a great deal of patience, or the wood will break. I could go on, but why?