Catastrophic Plate Tectonics Part III

By Jon Covey, BA, MT (ASCP)
Edited by Anita K. Millen-Covey, MD, MPH, MA

Figure 1

Thermal runaway of subducting oceanic slabs had important consequences for the Flood. The rapidly descending slabs heated the mantle surrounding them, which decreased mantle density and viscosity. Plumes of hot magma rose rapidly to the earth's surface and into the ocean basins, which jettisoned steam into the atmosphere, intensifying global rain and warming the ocean, which would drive the subsequent ice age. The magma formed hot new ocean floor and raised the sea level by isostatic rebound, because the hot oceanic crust was less dense than cool continental crust. Continued outpouring of magma also filled ocean basins, causing the sea level to rise even more and completely flood the continents. When the old oceanic crust was completely subducted and replaced by the new ocean crust, runaway subduction and plate motion stopped The new crust cooled, became denser than the continental crust, and sank down, producing deeper ocean basins which allowed the Flood waters to recede off the continents.

The following Q&A section continues selected parts of an interview with Dr. John Baumgardner, geophysicist working at the Los Alamos National Laboratory, by Carl Wieland and Don Batten. [Wieland] The entire interview is available in Creation ex nihilo.

We understand you've shown that as these floating blocks of rock push down into the material below, things get hotter, so the 'slipperiness' increases and there's a runaway effect. The faster they sink the hotter they get, so the faster they can sink.

JB: Yes-rock that comprises the ocean floor is colder, and therefore denser than the rock below it, so it can sink into the earth's interior [see Figure 1--Click on thumbnail for details. Based on Tarbuck, p. 403] The properties of the rock inside the earth, especially at the high temperatures that exist there, make it possible for the colder rock from the earth's surface to peel away and sink in a runaway manner down through the mantle-very rapidly.

So this 'happens' on your computer model all by itself, from the laws of science, over a short time-scale, not millions of years?

JB: That's correct. Exactly how long is something I'm working to refine. But it seems that once this sinking of the pre-Flood ocean floor starts (in a conveyor-belt-like fashion down into the earth, pulling things apart behind it), it is not a slow process spanning millions of years. It's almost certain that it runs to completion and, recycles' all of the existing floor in a few weeks or months.

You're part of a team of top creation scientists. This team is developing a model of catastrophic plate tectonics based on this mechanism, which believes the continents broke up (from a single landmass) during the Flood and not afterwards as some creationists have proposed.

JB: Yes. There is compelling evidence from the fossil-bearing sediments on the continents that the breakup occurred during the time these sediments were being deposited. We are convinced that this ‘continental sprint’ as it’s been called, occurred during the time of the Flood and was part of the mechanism for it.

Why is a six-day, recent creation important?

JB: I believe it's a pivotal issue in regard to the reliability of God's Word. It ultimately bears on the authenticity of Jesus, because Jesus put his stamp of authority on the writings of Moses. Taken at face value, the scriptures indicate that the original earth was a perfect world, one which included man and woman, one in which there was no death. There were no carnivorous animals-all the animals and man were given the green plants to eat. To reconcile the Biblical account of world history with our observations requires only acknowledging a catastrophe which destroyed all air-breathing land life except for that preserved in Noah's Ark. I believe there is no negotiation possible on this question.

You gave a poster presentation on this 'runaway rapid continental drift' mechanism at the American Geophysical Union meeting in 1994. At least some of the 6,000 scientists there saw it. What was the feedback?

JB: Many people were interested in the numerical techniques I used for such a calculation, because it's a significant computational challenge. Almost no one seemed to appreciate the implications of it. Actually, this concept of 'runaway subduction' [rapid sinking of the 'plates' as described earlier] has been in the literature for over 30 years. It was picked up in the geophysical community in the early 1970s, but for some reason interest disappeared. People in my field are not ignorant of this possibility; it's just not seriously explored.

Why do you think that is?

JB: Well, there's no real motivation to pursue it. Some toyed with the idea that such runaway effects might have been involved in recent volcanism in the southwestern U.S. But in their framework, they're not really looking for worldwide effects.

The above interview helps to clarify what Dr. Baumgardner and five other scientists on the Institute for Creation Research's (ICR) team have been working on. Their goal is to develop a catastrophic plate tectonic theory that has strong explanatory and predictive power and can compete with secular explanations of plate tectonics. The remainder of this article is based on their paper. [Austin]

What was the nature of the pre-Flood world? Anyone who wants to give a plausible explanation of the Flood must begin by listing the factors that would affect the course of the Flood.

Figure 2. Pre-Flood Earth Structure

Click on Picture for An elargement. [Tarbuck] shows the general internal structure of the earth. The magnified dark outermost layer, the brittle lithosphere, is 100 kilometers thick. The thickness of continental crust averages 35 kilometers (its density is 2.8 times water's density), and the oceanic crust is only 5 kilometers thick (density 2.9-3.0).

The mantle is far beneath the earth's surface (about 800 km beneath us). The only way geologists can explore it is through the observation of seismic waves that earthquakes produce and the use of mathematical models. Seismic S waves (Snake or undulate) are unable to travel through the liquid regions of the earth, such as the liquid outer core. Geologists discovered that S waves do travel through the mantle, indicating that it acts as an elastic solid.

Unlike the continental crust whose temperature increases rapidly with depth due to heat conduction from the upper mantle, the mantle's temperature increases much more gradually. This means that the mantle must have a more efficient way than conduction for transferring heat to the upper regions of the earth, otherwise it would have to be hundreds of times hotter than the upper mantle. If the mantle can act as a fluid, it can transfer heat from the depths of the earth to the upper mantle by convection, similar to the process seen in a glass pan of water heating on a stove, or beaker of water over a burner. Ghostly billows can be seen as heated water moves from the bottom to the top.

Under tremendous pressure, the solid mantle rock can act like a fluid or a solid. It is plastic. If sudden stresses act upon it, it reacts like a solid, as in the case of S waves generated by earthquakes. If allowed enough time, when stressed, it will flow upward like heated water flows upward through layers of cooler, denser water.

The lithosphere is approximately 100 km thick and is composed of brittle rock (See Figure 2). Below the lithosphere is the upper mantle which contains the low-velocity zone. This zone contains pockets of melt and crystals making up 10 percent of the zone. Both P (Punch) and S waves slow down when penetrating this zone. The asthenosphere (astheno-meaning weak) spans the zone of partial melting, descending to about 700 km where it meets the mantle. Molten rock expelled by volcanoes originates about 125 kilometers below the surface where partial melting of subducting oceanic plates laden with wet sediments occurs. Temperatures rise about 20-30'C per kilometer of depth. Water tends to lower the melting temperature. This hot, liquid magma has a lower density than the surrounding rock and buoys upward, eventually initiating volcanism. Asthenospheric rock, although not melted, is very hot and easily deformed. When the asthenosphere moves, it tends to move the lithosphere above it and is partly responsible for plate movement. However, slab pull seems more important for plate movement because it involves stronger forces.

God must have already separated the earth into crust, mantle, and core before the creation of life, because heavy elements contained within the earth would have sunk into the core and release tremendous gravitational potential energy, melting the crust and vaporizing the ocean. This structure (crust, mantle, and core) provides a natural driving mechanism for rapid plate tectonics.

Baumgardner explains that the mantle was less viscous before the Flood, [Baumgardner] because it was slightly warmer then. Lower viscosity of the mantle allows the thermal runway he and his ICR colleagues propose.

ICR's team also believes the oceanic and continental crusts were much as they are today. Before the Flood began, the continental crust was stable and sialic (silica and aluinina-rich, granitic rock); the oceanic crust was made of denser basaltic material (rich in magnesium and iron; mafic). These differences in density make continents float above the denser materials making up the ocean crust and the mantle.

Pre-Flood Sediments

By the time of the Flood, there were already considerable sediments. There was a biological need for sediments because God had to prepare a planet that could sustain life. Solid bedrock is unsuitable for plant growth and is a poor habitat for many burrowing creatures. We have to assume that when God caused the dry land to appear, He had to create enough soil on it to sustain life. This feature would give the appearance of age. Does this mean God deceived us? Some things must be created with the appearance of age if they are to be functional. Adam was created as an adult. Eve was created from Adam's rib as an adult. Must God limit His activity to the natural laws after He established them? If that's the case, should we believe the Egyptian plagues were simply well timed disasters and the Egyptian soldiers drowned in six inches of water'? When God stretched out the heavens, was the starlight coming from the stars likewise stretched to the red end of the spectrum? If so, this would mean the red shift is not evidence of a big bang. It corroborates the Bible's testimony of what God did.

When the land arose out of the sea, the water washed off the continent and left sediment behind. Sediments that are presumably pre-Flood (Precambrian >570 million years evolutionary), contain substantial quantities of all types of minerals. This makes it likely that there were pre-Flood sediments. It is not likely that the Flood generated all the sediments, including limestone, etc.).

ICR's team cites many possible events that could have initiated the Flood (Austin, p. 612), e.g., the hand of God, meteor or asteroid collision, and other things. They feel confident that slabs of oceanic crust broke loose, began subducting (sliding beneath the continents), and initiated the Flood.

Subduction

The movement of, oceanic slabs began sliding under the continents (subduction) along continental margins for thousands of kilometers. Today, subduction results by 1) sea-floor spreading from the mid-oceanic ridge where upwelling magma creates new sea floor and 2) slab pull (see Figure 1). As the slabs subducted, they deformed the mantle and generated heat. The heat made the mantle less viscous and more buoyant, which in turn made it easier for the slabs to fall into the mantle, generating more heat. This resulted in thermal runaway, which has been substantiated by Baumgardner's computer model. Of course, a computer simulation is not the real thing, but the results make it worthy of further investigation. All the present oceanic crust is from Flood or post-Flood times because modem ocean crust seems to date from then. [Austin, p. 612] This means all or most of the original ocean crust has subducted. The subducting slabs would have pulled the continents attached to them. If the slabs were moving several meters per second, so would the continents. When the continents collided at this speed, mountain belts such as the Appalachians, Himilayas, Caspians, and Alps were created.

Continued in Part IV.

References

Austin, S., Baumgardner, J., Humphreys, D., Snelling, A., Vardiman, L., Wise, K., "Catastrophic Plate Tectonics: A Global Model of Earth History," Proceedings of the Third International Conference on Creation, Edited by Robert E. Walsh, Creation Science Fellowship, Inc., Pittsburgh, pp. 609-621, 1994.

Baumgardner, J., "3-D finite element simulation of the global tectonic changes accompanying Noah" Flood," Proceedings of the Second International Conference on Creation, Edited by Robert E. Walsh, Creation Science Fellowship, Inc., Pittsburgh, Vol. 11 pp. 35-45, 1990.

Tarbuck, E., and Lutgens, F., The Earth: An Introduction to Physical geology, 2nd ed., Merrill Publishing Co., Columbus, based on drawings found on pp. 380 & 386, 1987.

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