But they haven’t just been sitting at the surface for 3.7 billion years – they’d journeyed almost to the center of the Earth and back.

The team conducted chemical analyses of these rocks and found certain iron isotopes with tungsten anomalies, which indicates they were leftovers from the crystals formed as the ancient magma ocean cooled. The find was made in Greenland’s Isua supracrustal belt, a region known to be home to some of the oldest exposed rocks on Earth and what may be the earliest evidence for microbial life. In a new study, researchers from the University of Cambridge have found the chemical fingerprints of this ancient magma ocean in rocks in Greenland that date back some 3.7 billion years. Unfortunately it’s hard to study this period in Earth’s past as tectonic activity tends to recycle older rocks, pushing them into the mantle and melting them down.īut evidence from that period may survive in other ways. Over time, as things calmed down that magma would have cooled and crystallized into rock, locking in the structure and chemistry of Earth and even contributing to its early atmosphere. These regular cataclysms are believed to have melted the rocky surface of the planet, creating a worldwide ocean of bubbling magma several hundred kilometers deep. That’s how our own Moon was born when the Earth was a mere toddler of 50 million years old. Proto-planets regularly crashed into each other, growing and merging and throwing off debris that became moons. Now, a team of researchers at Cambridge has found elusive evidence from that time, dredged up from an ancient crystal graveyard at the fringe of the mantle and core.Īround 4.5 billion years ago, the solar system was a much more volatile place. It may be a cool, comfortable paradise nowadays, but Earth had a pretty hotheaded youth – some scientists speculate that for a while the surface was one big ocean of magma.

Ancient space crystals