Scientists found Earths oldest rock on Moon

Pablo Tucker
January 27, 2019

This helped toss the rock back to the moon's surface.

The rock consists of quartz, feldspar, and zircon, some of the most common elements on Earth, but which are not as prevalent on the Moon.

Because the Moon was much closer to Earth at that point - about three times closer than it is now - it was in a better position for pieces of this debris to end up there.

It's possible that the fragment did indeed form on the Moon, but the conditions for that would be unlike anything we've seen on the satellite. However, conditions at no other time gathered from lunar examples would be required along with an example, in the lunar mantle, to have framed at huge profundities where many other rocks were combined together. Along these lines, the least complex elucidation is that the example originated from Earth. This rock was formed between 4 and 4.1 billion years ago, about 12.4 miles beneath the Earth's crust, yet the most curious thing about it that it was found far beyond our planet's surface - on the Moon.

Available evidence suggests that the fragment crystallised about 20 km beneath the Earth's surface, and was launched into space by a powerful impact shortly thereafter. But given that the Earth was subjected to impacts during the Hadean eon, when the planet was forming 4.6 billion years ago, bits of Earth on the moon don't seem surprising to Kring and his team. It was partially melted, and probably buried, by an impact about 3.9 billion years ago, then excavated by yet another impact 26 million years ago, the researchers said. The sample is therefore a relic of an intense period of bombardment that shaped the solar system during the first billion years.

The researchers believe that a large comet or asteroid hit Earth and sent the rock up through the atmosphere and into space.

However, the moon developed its own distinct geological characteristics, making its rocks easily distinguishable from those formed on Earth. Impacts of this magnitude were capable of pulling out materials from deep within the Earth's surface. The excavation of those craters ejected rocky debris, some of which hit the Moon.

Apollo 14 astronauts Alan Shepard and Edgar Mitchell apparently collected an ancient terrestrial rock when they explored the lunar surface in February 1971. As noted in the USRA press release, the researchers were fully anticipating that "the conclusion of a terrestrial origin for the rock fragment will be controversial".

But chemical analysis of the rock fragment shows it crystallised in a terrestrial-like oxidised system, at terrestrial temperatures, according to research published in the journal Earth and Planetary Science Letters. Dr. Katharine Robinson, a postdoctoral researcher at the LPI, was also involved in the study, as were Dr. Marion Grange (Curtin University), Dr. Gareth Collins (Imperial College London), Dr. Martin Whitehouse (Swedish Museum of Natural History), Dr. Josh Snape (Vrije Universiteit Amsterdam), and Prof.

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