CPT Q. 052: How is a narrow V-shaped rift maintained in CPT as two ocean plates rapidly move apart?

Q. 52. I would like to better understand the processes you envision happening at the mid-ocean ridges and on the ocean floor at the start of the Flood especially regarding the water jets. In your 1994 paper 1, the six author paper, you stated “Rapid emplacement of isostatically lighter mantle material raised the level of the ocean floor, displacing ocean water onto the continents.” Then regarding the water jet from your 2003 paper, bottom of page 14, it states “Another aspect of these jets is that seawater is converted to supercritical steam as the water penetrates downward through the fractured and porous newly formed seafloor, and then emerges almost explosively at the throat of the jet.” In your response to question 27 you described the water being exposed to molten rock in V-shaped rifts at the spreading center. I can see how the water could initially be a jet when water penetrates into the rift where molten rock is exposed. However, would not these fractures fill with lava and the lava spread out from the ridge over the 40 days? It seems the molten rock exposed to the water would widen over the initial few weeks of the Flood so that a wider and wider band of molten material would be exposed to the sea floor. Isn’t molten rock covering the sea floor from the ridge outward? As the molten material fills the V-shaped ridge and spreads out across the ocean floor, would this stop the jet?

It seems to me it would set off convection currents and heat the ocean strongly near the ridges. I don’t see how the water would remain exposed to only a narrow strip of molten material. As I understand it, the lava erupting spreads outward from the ridge making the seafloor rise as molten less dense mantle material is replacing the old ocean floor. You indicate that there is not much mixing of the supercritical water with the surrounding ocean water. But it seems to me the steam and supercritical water would mix with the ocean as the molten rock spreads out across the ocean floor. Please clarify.

Response: The main issue in view here is the mechanism and nature of the cooling of the rock column beneath the ocean bottom as this rock comprising new oceanic plate migrates away from an ocean rift zone during the Flood. As I have mentioned before, normal thermal conduction, or diffusion, of heat is simply incapable of cooling the ocean lithosphere as it exists today, either during the Flood itself or in the few thousand years that have elapsed since the Flood. If the many lines of observational evidence which indicate that today’s ocean lithosphere—every bit of it—has formed since the early Mesozoic part of the earth’s sedimentary record are trustworthy (and I believe these evidences are trustworthy), then this young age of the ocean lithosphere represents a major difficulty, not only for CPT, but for every model of the Flood cataclysm. This difficulty is that uniformitarian physics simply cannot account for such a rapid removal of heat. Honesty drives me to infer that God must have intervened in the physical laws He ordained in this particular aspect of the Flood cataclysm.

Regarding the history of radioactive decay, the Radioisotopes and the Age of the Earth (RATE) team came to a similar conclusion, namely, that God must have intervened during the Flood in the normal operation of the physical laws He ordained, both to increase dramatically the rates of nuclear decay and also to remove the heat which these accelerated decay rates unleashed. I as well as the other members of the RATE team did not take this step of resorting to the supernatural to account for the observations lightly or without earnestly exploring every other conceivable alternative. But the multiple lines of evidence logically seemed to admit no other alternative. It seems to me that the cooling of the ocean lithosphere to its present thermal state since it was formed during the Flood is a closely related issue that drives me to the same conclusion. Peter’s words in 2 Peter 3:3-6 seem to provide Scriptural confirmation that God did intervene supernaturally in the operation of His natural laws during the Flood.

With this background let me now address your question more directly. You ask:

“Isn’t molten rock covering the sea floor from the ridge outward?”

My answer is no. I base this answer on my conclusion that the seafloor rock had to be cooling at an elevated rate during the Flood itself. I reach this conclusion mainly from the observation that the lithospheric thickness, which is expressed in the current depth of the seafloor, varies smoothly as one moves laterally away from a mid-ocean rift. Lithospheric thickness in turn reflects the thermal state of that layer of rock. The greater the lithospheric thickness, the more cooling that has occurred since this rock was present at the rift. This seems to imply that during the main phase of the Flood, when exceedingly rapid motions within the mantle were occurring, somehow the rate of cooling of the newly formed lithosphere was also dramatically enhanced. This enhanced lithospheric cooling must have been an ongoing process during the Flood such that new lithosphere became progressively cooler with time as it moved away from the rift.

Although I have made this point before, let me make it here again, namely, that very little of the earth’s present seafloor likely formed in the post-Flood era. The reason is that, apart from some process that weakens the mantle (such as that responsible for CPT), plate velocities revert to those we observe occurring today, typically on the order of a few centimeters per year. A full spreading rate of 10 cm/yr, for example, means that a zone of new ocean floor only 0.45 km wide forms in a span of 4500 years. The conclusion that essentially all the present ocean lithosphere was formed during the Flood proper in turn suggests that the thermal state of today’s ocean lithosphere is representative of the thermal state of the oceanic lithosphere during the Flood itself. This implies that the rock very near to the rift zone was not molten, but solid.

Let me remark on your quote from the 1994 ICC joint paper:

“Rapid emplacement of isostatically lighter mantle material raised the level of the ocean floor, displacing ocean water onto the continents.”

Never was this intended to imply that this warmer, lighter mantle material was molten. Indeed, in the present mantle, most of the rock column even beneath a mid-ocean rift is solid! The 5-6 km of basaltic composition rock that is emplaced as molten magma primarily as dikes below the surface but also erupted to form pillow basalt on the surface is the product of partial melting (typically 15-25%) of some of the solid mantle rock below. In this setting, melting is primarily a consequence of the fact that rock melting temperature decreases as pressure decreases (also referred to as decompression melting).

More specifically, as plates on either side of a rift move apart, solid rock from beneath, deforming plastically, rises to fill the resulting gap. As this rock rises, it experiences a decrease in pressure. If this rock was near its melting temperature, as is generally the case for rock in the asthenosphere, this reduction in pressure causes some of the constituent minerals suddenly to find themselves above their melting temperatures, and partial melting begins. Once the melt fraction reaches a few percent there is enough porosity in the rock for the melt to migrate, because of its buoyancy, toward the surface. The resulting magma, formed by partial melting of the lowest melting temperature minerals in mantle rock, is basalt. It forms the top 5-6 km of a new oceanic plate. Below that basaltic layer is the solid residuum from the partial melting process as well as solid mantle rock whose temperature never exceeded the melting temperatures of its component minerals. Outside the zone into which basalt is being actively injected, all that is needed for the entire column to be solid is for the injected basalt to cool and crystallize. The sort of cooling I mentioned at the beginning of my response to your question above accomplishes this relatively close to the spreading rift.

This is the perspective I had in view when I wrote what you quoted from my 2003 ICC paper:

“Another aspect of these jets is that seawater is converted to supercritical steam as the water penetrates downward through the fractured and porous newly formed seafloor, and then emerges almost explosively at the throat of the jet.”

I was assuming a cooling rate for the oceanic lithosphere sufficiently high such that, within a few hundred of meters of the centerline of the V-shaped rift, the basaltic wall rock was completely crystallized, solid, and cool enough to have cracked and fractured and thus able to provide paths for ocean water from above to be sucked into the throat of the jet.

Finally, I would like to comment on the issue of a temporary rise in global sea level produced by warmer ocean lithosphere temporarily replacing colder. For upper mantle rock the volume coefficient of thermal expansion is on the order of 3x10-5/°C. This means that an 80 km thick layer beneath the ocean bottom that is on average 400°C warmer will cause the ocean bottom to stand 1 km higher. While I once believed a rise in global sea level of several hundred meters or more was needed to account for the sedimentation and erosion patterns on the continents, I am no longer convinced this is so. The main reason for my change in outlook is my recent awareness that the earth may have been rotationally unstable during the Flood. As I have indicated elsewhere, such rotational instability causes large amplitude, high velocity tsunami-like waves to sweep over the continents with only small overall changes in sea level.