Earth's oldest rock found on Moon

Earthrise from Moon

The rock was subsequently mixed with other lunar surface materials into one sample.

Analyzing lunar samples collected by the Apollo 14 mission, the researchers found that the rock consisted of 0.08 ounces of quartz, feldspar and zircon, minerals that are fairly commonplace on Earth but "highly unusual on the Moon", according to the statement.

An global team of scientists found a tiny fragment - weighing less than an ounce - composed of quartz, feldspar and zircon in one of those moon rocks, according to a news release about the discovery. And he believes that more may be found.

"In addition, the chemistry of the zircon in this sample is very different from that of every other zircon grain ever analysed in lunar samples, and remarkably similar to that of zircons found on Earth".

A lot of the rocks we have on Earth aare pretty old, but none of them were around when our planet was first formed.

Kring suspects the conclusion of a terrestrial origin for the rock fragment will be controversial.

It crystallised about 12.4 miles below the surface between 4 billion and 4.1 billion years ago, when the Earth was young.

That seems to have changed, however, because a group of scientists recently announced they've found a rock that formed only half a billion years after the Earth itself.

But is it any less of a coincidence that an Earth rock could have ended up on the moon?

Nemchin is quick to point out that he and his team are not 100 percent certain that the sample originated on Earth although the evidence would suggest that.

Chemical analysis of the rock fragment showed that it crystallised in a terrestrial-like oxidised system, at temperatures found on the Earth, rather than in temperature conditions that are characteristic of the Moon.

"However, a simpler explanation is that this piece was formed on the Earth and brought to the surface of the moon as a meteorite generated by an asteroid hitting Earth about four billion years ago, and throwing material into space and to the moon".

An worldwide team associated with Center for Lunar Science and Exploration (CLSE) in the U.S. found evidence that the rock was launched from Earth by a large impacting asteroid or comet. Previous work by the team showed that impacting asteroids at that time were producing craters thousands of kilometers in diameter on Earth, sufficiently large to bring material from those depths to the surface.

After the rock came to rest on the lunar surface, another impact 3.9 billion years ago partially melted and buried it, scientists believe.

"For that reason it provides a neat achieve of impacts, as it is unlike the Earth, which is affected by erosion and plate tectonics that disturb impact craters".

Around 26 million years ago, an asteroid hit the moon and created the Cone Crater.

"It is an extraordinary find that helps paint a better picture of early Earth and the bombardment that modified our planet during the dawn of life", one of the researchers said.

The center is part of NASA's Solar System Exploration Research Virtual Institute.

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