This violent chapter likely took place about 4.5 billion years ago, less than 100 million years after Earth\u2019s formation began, during the fiery Hadean period \u2014 a time when the young planet was anything but hospitable.<\/p>\n
Sean Raymond, an astrophysicist at the Bordeaux Astrophysics Laboratory, discusses the formation of the Solar System according to the standard scenario of accretion of planetesimals giving rise to planetary embryos. \u00a9 Ideas in Science<\/p>\n
Potassium isotopes: keys to a hidden past<\/p>\n
A team from MIT recently announced a striking discovery: rare remnants of the proto-Earth may still exist within ancient rocks and meteorites. Their findings, published in Nature Geoscience, came from an analysis of potassium isotopes in samples from Greenland\u2019s Isua region, Canada\u2019s Nuvvuagittuq belt, and South Africa\u2019s Kaapvaal craton \u2014 all dating back more than 3 billion years.<\/p>\n
The researchers also studied much younger basalts from R\u00e9union Island and Hawaii\u2019s Kama\u2018ehuakanaloa volcano. These rocks, though recent, came from deep \u201chot spots\u201d in Earth\u2019s mantle that may have preserved untouched material from our planet\u2019s earliest days.<\/p>\n
![\"roche_Nuvvuagittuq_NASA_Astrobiology_Institute_\"](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2025\/10\/roche_Nuvvuagittuq_NASA_Astrobiology_Institute_-1024x768.jpeg\")
A photograph of a metamorphic rock outcrop at Porpoise Cove, in the Nuvvuagittuq supracrustal belt (Canada). Some of these rocks have a Sm\/Nd ratio indicating an age of over 4.0 Ga. They could therefore be among the oldest rocks on Earth. \u00a9 NASA Astrobiology Institute<\/p>\n
Because Earth\u2019s surface has been reshaped over billions of years \u2014 from relentless geologic churn to ancient meteor bombardments \u2014 uncovering traces of its infancy is almost impossible. But MIT\u2019s team managed it by focusing on potassium isotopes with mass numbers 39, 40, and 41.<\/p>\n
As MIT explained, potassium on Earth usually appears in a familiar mix of isotopes dominated by potassium-39 and -41. The rarer potassium-40 exists only in trace amounts. Yet some meteorites showed distinctly different isotope ratios, suggesting they predated the chemical makeup of modern Earth. In essence, any material showing that same imbalance could be a relic from before the Moon-forming impact.<\/p>\n
![\"30392_sediment](\"https:\/\/www.newsbeep.com\/il\/wp-content\/uploads\/2025\/10\/30392_sediment-isua_Francis-Albarede_01-1024x768.jpeg\")
The Isua sedimentary layers (3.85 billion years old) in Greenland. These rocks are the oldest known sediments in the Solar System. \u00a9 Francis Albarede<\/p>\n
Ancient signatures in stone<\/p>\n
In rock samples from Greenland, Canada, and Hawaii, the scientists found an isotopic signature unlike most Earth materials \u2014 a deficit of potassium-40. This shortfall fits perfectly with what would be expected from matter dating back to the early Hadean era, preserving the meteorite fingerprints of Earth\u2019s earliest state.<\/p>\n
To confirm, researchers simulated billions of years of geodynamic evolution, testing whether normal mantle processes could mimic such ancient imprints. The results said no: their models always produced slightly higher potassium-40 levels, matching modern rocks instead.<\/p>\n