Planet Earth in the distant past was not in a molten state and is not on the way to cooling. (Otherwise, there would not be any changes inside, except for the direction along the path of entropy. Simply put, the Earth would cool down calmly, slowly contracting, decreasing in volume. In reality, everything happens the other way around: the Earth is expanding.) However, this concept does not give full presentation on the merits of the case.

The internal heat of the Earth is not of radioactive origin

The rocks that make up the earth's crust say to themselves that they at one time underwent a melting stage, although not all with such obvious signs, but most of them. If you do not resort to unnecessary chewing, then it is worth saying more simply: the melting of the Earth's substance happened, but not once on a general scale - of the entire available mass, but in parts.
The fact of the matter is that the very mechanism of the melting process remains unknown. This process is not so unknowable, although it is obvious and accessible to the eye, but apparently far from thinking.
For some reason, all scientific thought is so firmly entrenched on the concept of radioactive heat, it does not even generate separate units that they would question it and start looking for or looking for some other sources of heat. The role of radioactivity in creating powerful thermal forces is so incredibly small that even experimentally it was not possible to support the opinion, not to mention the facts that clearly deny the role of radioactivity.
And speaking about the role of terrestrial melting (and this actually takes place) already itself generates contradictions in the concept of radioactivity. No one has yet cited a single example as the fact that a concentration of radioactive substances corresponding to the required calculated amount was found in freshly erupted igneous rocks. And this is already an obvious and indisputable fact. So where, then, did the radioactive elements that led to the process of melting rocks go? Settled lower to melt a new batch again?

The gas component is an indicator of the vital activity of the planet

As for the degassing of the substance, then there is also a misconception with a good juggling. If scientific thought followed at least approximate true concepts of the origin of water, then the concept of degassing would be interpreted in a completely different way. Any eruption, it is impossible without admixtures of various gases and water vapor. This is a solid pattern. But it should be considered not from the point of view that, they say, before the time of melting, all these components were included in the composition of this rock, and after remelting they were released.
How the atmospheres of planetary bodies arise there, we will not resort to a detailed explanation. Let us note only one thing, that not only "... in other planets the atmosphere disappears altogether due to a number of facts," it disappears in all, without exception, and not in the same period of time of their existence. It exists insofar as they have vital activity. Was there not at one time an atmosphere even in small planetary bodies, for example, Ceres and her like? And the Moon had its own atmosphere, just like its satellites of the major planets have at the present time. But even there it is temporary. True, in some bodies, or rather around them, the atmosphere lingers longer until it disappears completely, in others it will not have time to accumulate, as living conditions in space make it disappear. The atmosphere of a planetary body is the most reliable indicator of its vital activity. It is inextricably linked and dependent on the processes taking place inside the planetary body in a direct or indirect way.

The earth's crust has reincarnated only once - during the birth

Regarding the creation of the earth's crust, modern thought is partly correct ("... the continental crust is the result of partial (?) Direct smelting from the mantle"), and partly not ("and partly - geochemical processing of the same smelted ..."). What does it mean? According to the thought expressed, it means that after smelting, the erupted to the surface undergoes chemical transformations. Is it true? If even in some scanty percentage (although we overestimate) chemical transformations have passed or are undergoing, then all the same it should not be generalized and attributed to a significant mass of the earth's crust. Traces of such transformations are still unknown.
But the assumption is completely wrong. What reversibility of the process can be here? And what is “basification of the granite layer”? How to comprehend it? There is no transition of the continental crust to the oceanic one. It would be a very big mistake if we consider the modern oceanic crust as the former site of the disappeared mainland. This is just absurd.
Of course, there are a number of tempting facts for such an opinion to arise, and the most basic of them is the shelves. But the shelves have never been a continental crust, that is, such that at one time (meaning at its inception) it could be the surface of the day and collide with the air. Even though the shelves may have direct signs of continental crust - granite, these areas remain completely oceanic crust.
If, by analogy, in the opposite direction, then most of the modern continental crust can also be called oceanic, among which you can find only a small percentage of pure continental crust, which has never had anything to do with water spaces. Only the conditions of geological development have the right to make such a division, and not our reasoning on the basis of certain features.
Lacking specific concepts about the essence of the origin of the crust of the two types of each separately, it can lead everyone to the idea that the oceanic crust is traces of the disappeared continental. How else to explain the absence of a significant thickness of the granite layer? But there is at least some confirmation of the expressed thought, scientists did not think about it.

The primary crust was born at the same time

The basalt layer could not have arisen first. It originated simultaneously with the mainland crust, although at present such exists without it. There is no doubt that the initial melting of rocks was of a general, so to speak, global nature. But speaking about this, one should keep in mind the apparent dimensions of the planetary body at that time, and not modern ones. And only after the complete completion of the global process, a continuous flow of local processes begins in the deformation zones of the earth's crust. In general, this process is not associated with the foci of volcanoes, but is a force that prompts the emergence of the latter. This process is accompanied not only by the formation of basic or basaltic magma, but also those sedimentary rocks, the origin of which we attribute to exogenous processes. And there was no interaction between the primary material of the mantle and the volcanogenic masses of the basalt layer. Here everything went on as usual in the order of the turn, only in one direction.

Translated from Земна кора – результат поступової виплавки внутрішньої речовини планети

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