Evidence of Earth's ancient magma ocean discovered in Greenland

Scientists have discovered something interesting in Greenland that provides evidence that much of the Earth was once entirely molten rock. The evidence came from eons-old rocks found in southern Greenland. Researchers say that little is known about the Earth and conditions on the planet during the Hadean Eon. This period characterized the initial formation of the Earth and the stabilization of the core and crust of the planet.

The Earth's early atmosphere also formed during the Hadean Eon. The study was published last week, showing results of work on the analysis of rocks that were billions of years old from the Isua supracrustal belt that contains the oldest known rocks on the planet. During their investigation of the rocks, scientists found chemical traces of a magma ocean.

The samples where the chemical traces were discovered date back to 3.7 billion years old and showed high levels of heavy iron isotopes measured using chromatography and mass spectroscopy. The team also discovered hafnium and neodymium isotopes along with rarer tungsten isotopes, which they say stems from an "ancient parent isotope" that only existed during the first 45 million years of the Earth's life.

Researchers said that hafnium and neodymium are the most interesting isotopes discovered because they are very hard to modify and required detailed investigations into their chemistry. Ultimately, researchers found that the iron isotopes confirmed that the Isua rocks had been made of parts of Earth's interior that formed 4.5 billion years ago from the crystallization of the magma ocean.

Crystal residues melted and mixed with other molten rock when it moved to the earth's upper mantle carrying isotopes along with rock from both the lower and upper mantle. Scientists admit that how exactly the material emerged on the surface is less clear. Some scientists believe catastrophic impacts during the formation of the Earth and Moon could have generated enough energy to melt the Earth's interior. That material would've eventually cooled and crystallized, forming rock of the type the scientists discovered.