Catastrophic Plate Tectonics Part II

By Jon Covey, B.A., MT(ASCP)
Edited by Anita K. Millen-Covey, M.D., M.P.H., M.A.

About twenty-five years ago, many geologists still hadn’t accepted the idea of moving tectonic plates. One reader called after she received part one of this series. She remembers teaching the separation of the original supercontinent and that the continents still move. She said that one person in her class scoffed, ridiculing the Bible’s inference that the continents moved apart.

A mere three or four years ago, geologists might have ridiculed ICR geologists for suggesting that slabs of oceanic crust would fall through the mantle, reaching thermal runaway. How could oceanic slabs sink into the mantle under their own steam? Some would have been thought it pure poppycock. They would not want to accept the idea that slabs of oceanic plate in thermal runaway went crashing into the earth’s core at five meters per second. That was only a few years ago. What would they think now that some leading geologists believe there was a time when the plates moved faster? What would they say now that some researchers are convinced of "slab pull?" [Kerr] Consider Kerr’s report in Science.

On one level, why the plates move is no mystery at all. Plates are just the upper limb of a vast, heat-driven circulation system that stirs the planet to its depths. But pinpointing where the forces that actually move the plates are concentrated has been difficult, given researchers’ fuzzy view of Earth’s interior and the limited ability of computer models to simulate the planet’s complex dynamics. Now the most realistic computer models of plates motions to date have strengthened the case for one of the front-running driving forces. Says Mark Richards of the university of California, Berkeley, who helped develop one of the models, "We tried to show clearly that the main driving force is slabs," churning the mantle as they sink into trenches and thus dragging the plates along.

Other researchers agree that the modelers have strengthened the case for slab pull. Even if these simulations hold up, however, they don’t solve the full mystery of plate motions. At the same time as the computer models support slab pull, one group of researchers is saying that peculiar stirrings of the mantle beneath South America imply a different driving force in that part of the world.

One of the ICR geologists involved in research on catastrophic plate tectonics, Dr. John Baumgardner, spoke with Carl Wieland and Don Batten in an interview for Creation ex nihilo (a creationist family magazine, see inserted brochure). [Wieland] They said:

A 1993 New Scientist article spoke highly of your (Baumgardner’s) 3-D supercomputer model of plate tectonics. [New Scientist]

Baumgardner replied:

There are to my knowledge three other computer codes for modeling the earth’s mantle and so on, in the world. These other three use a mathematical method not so well suited for the modern parallel supercomputers. The one I developed used the finite element technique and performs very well on the new, very large supercomputers. So, many of my colleagues are recognizing it as the most capable code in the world. Last year NASA funded this effort as one of the nine grand challenge projects for the next three years in the High Performance Computing and Communication initiative, and are supporting two post-doctoral researchers to collaborate with me to improve it, and apply it to study the earth. This code is comparable to what are called general circulation models for the atmosphere and oceans, which are some of the largest codes in the world in terms of how much machine power they consume. It’s got lots of physics in it to model the details of the mechanical behaviour of the silicate rock inside the earth. My present focus is to make the representation of the tectonic plates even more realistic. So the code is in an ongoing state of development, but it’s come a long way in the last 15 years.

Continued Part III

References

Kerr, R.A., "Earth’s Surface May Move Itself," Science 269:1214-15, 1995.

New Scientist, January 16, 1993, p. 19 "How a supercontinent went to pieces."

Wieland, C., and Batten, D., "Interview with plate tectonics expert Dr John Baumgardner," Creation ex nihilo 19(3)41, 1997.