New research by the University of Cambridge has found evidence in ancient rocks from Greenland that the Earth was at a time almost entirely molten. The study yields information on an important period in our planet’s formation when a deap sea of magma stretched across Earth’s surface and extended hundreds of kilometers into the interior.
The gradual cooling and crystallization of this magma ocean set the chemistry of Earth’s interior. It was a defining stage in the assembly of our planet’s structure and the formation of our early atmosphere.
Researchers have now found the chemical remnants of the magma ocean in 3.6 billion year old rocks from southwestern Greenland.
These findings support the long-held theory that Earth was once almost entirely molten at a time when the planet started to solidify and develop the chemistry of its internal structure.
The new research shows that the rocks found on Greenland also preserve rare evidence which even predates plate tectonics with remnants of crystals left behind as the magma ocean cooled.
The presence of iron isotopes confirmed to the team that the rocks were derived from parts of the Earth’s interior that formed as a consequence of magma ocean crystallization.
University of Cambridge. (2021, March 12). Traces of Earth’s early magma ocean identified in Greenland rocks. Phys.org. https://phys.org/news/2021-03-earth-early-magma-ocean-greenland.html