CPT Q. 027: If CPT actually occurred, how did the oceans avoid being heated to the boiling point?
Q. 27. How can the oceans avoid being heated to the boiling point as all the present ocean crust is rapidly generated via seafloor spreading along the mid-ocean ridges during the Flood?
Response: The question of how the oceans might escape being heated to the boiling point – as the process of seafloor spreading during the Flood generates enough new ocean floor to more than replace the entire area of today’s deep ocean basins – is indeed an important one. The best answer I have at this point is that the contact between the ocean water and the molten rock was restricted to an extremely small surface area, namely, the bottom of the V-shaped rift valleys between adjacent diverging oceanic plates. Here ocean water would quickly reach temperatures near to that of the molten rock, about 1100 °C. Water at these temperatures at depths of 5-10 km below the ocean surface would, of course, be super critical. The result would be the formation of a tight linear chain of steam jets originating from near the bottom of the V-shaped rift. What sort of velocities might the steam within these jets have? One can obtain an upper limit for the steam velocity at the core of the jets as they emerge from the ocean surface by assuming that the kinetic energy equals the change in thermal energy minus the change in potential energy. Let’s assume the jets form 5 km below the surface, and that the temperature in the jet core at the ocean surface, as a result of expansion, is 100°C. Using the value for the specific heat of steam at 100°C of 2080 J/kg-°C, we obtain a value of the specific kinetic energy of:
1[(1100°C – 100 °C) x 2080 J/kg-°C] – [5000 m x 10 m/s2 x 1 J/(kg-m2/s2)] = 2.0 x 106 J/kg
Given that the specific kinetic energy is 0.5 u2, where u is speed, one obtains an estimate for peak core speed of 2000 m/s, or 4500 mph, which is clearly supersonic.
A numerical simulation of this process would be extremely helpful in exploring many of the interesting details. (If anyone knows of someone with the expertise and desire to model these jets and their interaction with the water column they penetrate, I would deeply appreciate making contact.) However, even without a numerical simulation to explore the details, several general conclusions I believe can be reached that bear on how much heat gets transferred to the oceans. The first conclusion has to do with the path of the water which supplies the jets. Because the jet is basically expanding into the near vacuum of space, there is a pressure drop inside the jet that persists down to the base of the jet itself. Thus the small region at the base of the jet is almost certainly at a pressure substantially below the hydrostatic pressure of its surroundings. This means that there is a strong tendency for the water supplying the jet to be drawn out of the rock immediately surrounding the jet. Basalt contracts and cracks as it cools, and therefore pathways for water to migrate from the nearby ocean bottom toward the bottom of the rift would tend naturally to form as that water cooled the basalt in the near vicinity of the rift. Note that the water heated by this process migrates downwards toward the bottom of the rift where the pressure is low and not upwards to heat the nearby ocean bottom water.
A second important conclusion is that cooling by circulating water which occurred in the near vicinity of the rift was sufficient at least to solidify what had been molten basalt. That is, the cooling was sufficient to produce a solid rind on the rock surfaces on the sides of the rift, within the fractures in the adjacent rock volume, as well as on the top of the newly formed ocean floor away from the rift. Because solid basalt has low thermal conductivity, heat transfer from the newly formed ocean floor away from the rift and into the overlying ocean water, though considerable, was dramatically less than what was occurring within the rift itself.
A third general conclusion is that with little uncertainty the vast majority of the heat associated with the jets was transported through the oceanic layer very quickly, at highly supersonic speed, in the core of the jets. The mixing of steam with the ocean water in the edges of each jet, although important to quantify in a numerical model, almost certainly represents a small fraction of the total heat and mass flux of the jet.
A fourth, qualitative conclusion is that shocks must play a major role in the overall interaction of the supersonic steam with the surrounding ocean water. The large pressure jumps between the interior of the jet and the surrounding water must be maintained by a structure of more or less steady-state supersonic shocks. It is likely that these shocks will serve to reduce mixing significantly beyond what would occur otherwise. The overall conclusion here is that a large fraction of the heat transferred from the hot basaltic rock to the ocean water plausibly escaped to space via these supersonic steam jets, without large scale heating of the bulk ocean. A careful numerical simulation is clearly needed to obtain a more quantitative assessment of this issue.
Another consideration entirely separate from the mechanics of the steam jets is the fact that the oceans today are very strongly stratified with respect to density. This makes the parcels of water with different densities in today’s ocean very difficult to mix together. As a result of this stratification, very little mixing occurs today in the vast majority of the ocean volume. Ocean currents tend to be relatively restricted in their lateral and vertical extent. Most of the mixing that does occur takes place in the topmost 25-200 m in what is called the ‘mixed layer’ and is largely a result of wind exerting tractions on the ocean surface. There is no reason to suspect that the ocean before the Flood was not also strongly stratified. If this conjecture is correct, then at least some volumes of the pre-Flood ocean, along with some of the sea life they contained, may well have survived the violence of the Flood relatively unmixed and intact.