"... Scientists have modeled the conditions that are typical for the bowels of the Earth, in particular, a temperature of about 1.4 thousand degrees Celsius and a pressure 20 thousand times greater than at the surface of the planet. With such parameters, the silicon dioxide contained in the mantle enters into chemical reaction with hydrogen, which leads to the formation of water and silicon hydride.
Geophysicists have found that this kind of reaction can occur at a depth of 40 to 400 kilometers from the surface of the planet.”
https://cont.ws/@vmrus1/507332
So, at the beginning of the Flood at a depth of 400 km from the Earth's surface, a chain of chemical reactions took place. One of them was the reaction of silicon dioxide and hydrogen to form water and silicon hydride. Along the way, as a result of these reactions, a huge amount of heat was released. Water, formed at a depth of tens of kilometers under a pressure of tens of thousands of atmospheres, had a density much less than the density of the surrounding mantle. Under such conditions, water under the action of a buoyant force rushed to the surface of the Earth. When the temperature of the surrounding magma and pressure corresponded to the parameters of the transition of water from a liquid state to a gaseous one, an explosion was occurring. As you know, the volume of water during the transition from liquid to gaseous state increases by 600 times. Under such conditions, excess pressure was created inside the Earth, which led to breaks in the Earth's crust and the release of magma and superheated steam into the atmosphere. Thus
"the fountaines of the great deepe" (Gen.7:11) (KJV1611) were broken up. Scripture tells us the sequence of events. First,
"the fountaines of the great deepe" were broken up, and then
"the windowes of heauen were opened."
We have already considered the mechanism of breaking up the fountains of the great deep. Now we consider how the windows of heaven were opened. Superheated steam of the order of 1400 degrees Celsius rushed up and reached the water (ice) shell of the Earth, which kept the pressure acceptable for the normal life of large dinosaurs moving on land, and other antediluvian animals and humans. It also created a greenhouse effect on Earth, which contributed to the rapid growth of vegetation and was a condition for a mild, uniform climate throughout the Earth. The temperature of this shell was about -180 degrees Celsius. The greatest intensity of the melting of the ice shell was over the areas of breaks in the Earth's crust. In other words, the intensity of the melting of the Earth's ice shell was not uniform in different places. Thus, the superheated steam in contact with the ice shell, firstly, condensed, and secondly, affected the ice shell, destroying it. And
“the raine was vpon the earth” (Gen.7:12). The thickness of the ice shell and its temperature were sufficient to compensate for the huge amount of heat released during the eruption of magma and the release of superheated steam into the atmosphere. At a certain stage of the Flood, the eruption of magma and the spreading of newly formed continents along it, so to speak, took place already under water. The volumetric expansion of the Earth took place. When the ice shell melted through in some places, the atmospheric pressure began to fall smoothly. Atmospheric air escaped through these thawed patches beyond the outer limits of the ice shell, now being held by the Earth's gravitational attraction. The decrease in atmosphere pressure also contributed to the decrease in ambient temperature in accordance with Charles's law. Thus
“the windowes of heauen” were opened (Gen.7:11). At the end of the 40th day after the start of the Flood, the Earth's ice shell was completely destroyed. And
“the raine from heauen was restrained” (Gen.8:2). The remnants of supercold and magnetized ice rushed to the surface of the earth under the influence of the Earth's magnetic field. The greatest amount of it downed out in the subpolar regions of the Earth, due to the specifics of the magnetic field. It is worth adding that the antediluvian ice shell of the Earth was held due to the magnetic field of the Earth according to the Meissner effect. It is known that supercold ice is magnetized.
There were no oceans before the flood. The whole globe was
"the drie land", which God called the Earth and on which were the Seas (Gen.1:10) (KJV1611). Before the Flood, people and animals could freely move around the antediluvian Earth with a radius of 3700 km due to the gravitational force of the water (ice) shell located above the earth, or rather around the Earth. This is especially true of large dinosaurs moving on land. If the radius of the Earth had not increased during the Flood from 3700 km to 6371 km, then the total gravitational force of the ice shell that poured out on the Earth for 40 days in the form of rain, and the gravitational force of the Earth, would simply crush all the inhabitants of the Ark. This follows from Newton's formula for universal gravitation.
Large dinosaurs living on land could not exist after the Flood due to changes in the conditions of existence on Earth. The air pressure has halved; the oxygen content in the air before the Flood was about 40%; also slightly increased the force of gravity after the Flood. In such conditions, large animals can live only in the aquatic environment.
"Christians" do not know about this and do not want to know.