Researchers have discovered “lost continents” from 4 billion years ago

The idea we have of the early Earth involves a huge ball of incandescent magma and conditions incompatible with life. The problem? That there are no rocks from 4.3 billion years ago to confirm this consolidated theory. What we do have are some microscopic crystals called zircons. And zircons are telling a different story, according to this study by a research team at the University of Wisconsin-Madison. published in Nature. What zircon says. Regarding the behavior of the Earth’s surface, geology valued two ideas for that period known as Hadean: that there was a plate tectonics where one plate sinks under another or that the Earth had a kind of stagnant lid, a rigid and hot surface where heat only escaped through large columns of magma. Well, neither one nor the other, both: zircons leave evidence of an Earth that already had oceans, liquid water and a crust that alternated both systems. John Valley, the University of Wisconsin-Madison geoscientist who leads the study explains that “There were about 800 million years of Earth’s history in which the surface was already habitable, although we have no fossil evidence and we do not know when life first emerged.” Why it is important. Because they determine that the Earth did not choose a single model, but rather that both processes took place at the same time in different places. Of course, it was not a stable plate tectonics like the one that exists today, but rather it had violent and short episodes of sliding of the edges of one plate under another (subduction) that coexisted with large jets of magma that rose from the interior of the Earth. This discovery is key to understanding how the Earth’s surface moved, the formation of continents and life. On the one hand, without tectonics, the felsic continental crust that floats on the mantle and makes up the lands on which we live would not exist. On the other hand, plate tectonics regulates the climate and recycles nutrients, so knowing when it started working helps understand when the Earth became a place compatible with life. How they analyzed it. The John Valley team analyzed the popular zircons from Jack Hills (Western Australia). These sand-sized minerals are a kind of time capsule, housing the only direct record of Earth’s first 500 million years. They were looking for chemical “fingerprints” that would reveal where and how they were formed, for which they used technology WiscSIMS high resolution. They then compared the results of the analysis with other zirconiums from the Hadic Eon found in Barberton (South Africa). Each one told a different story. Surprises in the “DNA” of the mineral. 47% of oceanic zircons had high levels of Uranium compared to Niobium, indicating that they formed in subduction zones where ocean water sinks into the mantle. On the other hand, the South African zircons show that they were born from virgin rock from the planet’s interior, confirming the classic ‘stagnant lid’ theory by which the Earth’s first solid surface was rigid and immobile. Or what is the same: while in Australia the crust sank and created protocontinents, in what is now South Africa the Earth behaved differently, with a rigid and stagnant crust. That is, the early Earth was a mosaic of tectonic styles. The Earth did not go from being hell to what it is today overnight, but rather it was a hybrid process and generated the necessary conditions for life sooner than we thought. In Xataka | We know it as “the red planet”, but 3.37 billion years ago Mars was almost as blue as Earth In Xataka | 4.5 billion years of Earth’s history, summarized in a spectacular video map Cover | Tomáš Malík and Javier Miranda

The “lost continents” of our planet are leaving their trail in an unthinkable place: the earth’s magnetic field

Life as we know it depends largely on the stability of the Earth’s magnetic field. But this stability (or the absence of this) depends in turn on factors that we still do not understand. Some of these factors are in the outer space, others instead are thousands of kilometers hidden under our feet. From the bottom up. Huge geological structures located in the land mantle They could be contributing To destabilize the magnetic field that protects the land from radiation and particles from space. These are the “sunk continents”, the large provinces of low speed (LLVP). Sunk continents. This last name is due to the fact that these rock masses located in the deep layers of the land mantle stand out from the rest of its surroundings because the seismic waves move more slowly through them. Through this method we know the existence of two large LLVP, one located under the African tectonic plaque and the other located under the peaceful plaque. We do not know exactly what they are or what is the origin of these rock masses. A hypothesis indicates that could be remains of the impact between the primal earth and a second planet called Theia. The Moon would be one of the results of that impact, another would be that part of The remains of Theia would have been “embedded” on earth, specifically in the mantle, giving rise to these “lost continents.” However, other studies have pointed out that these masses would be formed, at least partially of ocean cortex buried through subductive geological processes, which would make them more close to “lost continents” of the surface of the earth. The new study can be linked to this last hypothesis. Fed by a “fire ring.” The team He modeled the movements Convectives of the land mantle, also creating a reconstruction of the possible movement of the tecton plates on the surface of the Earth in the last 1,000 million years. Thus they found indications that the African dough would contain older and more “mixed” than the peaceful mass, which would contain 50% more oceanic crust, a more “young” cortex and different from the surrounding mantle. This could be explained with the call “Pacific Fire Ring”, A vast network of failures, many of them subductive that little by little they engulf part of the earth’s crust. This “banquet” would have been producing for at least 300 million years and would be serving to feed the Pacific LLVP. The details of the study were published In an article In the magazine Scientific Reportsof Nature. In diversity is the key. Until now, intuition pointed out that these two underground “continents” had a similar composition. The reason is precisely that the two slow down the passage of seismic waves in a similar way, which leads us to the intuition of thinking that these are very similar in their characteristics. However, the team responsible for the new work indicates that this may not be the case. The reason is that the temperature is more than the material that makes these regions slow the waves that cross them. The balance is complicated. The formations are more or less opposite in the Terrestrial globe, which in principle is great news: since these masses influence the way in which the temperature of the earth’s core is spread in higher layers, which in turn affects the conductive movements inside the nucleus of the planet. Since these movements are those that allow the existence of a magnetic field On Earth, the way in which they occur has a lot of impact on this field. If the LLVPs are different, the way in which the field is generated ceases to be symmetrical as one would expect, which gives rise to the appearance of imbalances. Discussing the different hypotheses. As we pointed out at the beginning, the new study can be linked to the idea that the LLVPs are the result of the sinking of earth cortex pieces and not the remains of a planet of the original solar system. Although the study does not offer conclusive evidence confirming this first hypothesis, It can be seen as a new more test in this address. In Xataka | Julio Verne was right: there are three times more water in the depths of the earth than in all oceans together Image | Oxford University; Panton, Davies, et al. (2025) / NASA/Goddard Space Flight Center Scientific Visualization Studio

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