Discovered a very ancient fragment of terrestrial origin in a lunar sample brought to Earth by Apollo 14 astronauts.
It is a fragment of 2 grams of earthy origin and its composition based on quartz, feldspar and zircon, common minerals on Earth but not on the Moon. Chemical analysis confirmed that the fragment has crystallized in an oxidized system similar to Earth's, at temperatures very different from the extreme ones that characterize our satellite.
According to studies by an international group of scientists, associated with the Center for Lunar Science and Exploration (CLSE), which is part of NASA's Solar System Exploration Research Virtual Institute it is plausible that the rock has crystallized about 20 kilometers below the earth's surface
in a period between 4 and 4.1 billion years ago. This team of scientists would seem to have found the evidence that the rock in question was splashed on the Moon when a large asteroid, or a comet, collided with the Earth.
This impact would have been able to expel material from the surface of the Earth, projecting it into space through the primitive earthly atmosphere, where it would collide with the surface of the Moon (which at the time was three times closer to the Earth than it is now), about 4 billion years ago. Subsequently, the rock would seem to have mixed with other materials of the lunar surface, to constitute a single sample.
It can not be excluded that the sample is not of terrestrial origin,
that is, that has actually crystallized on the Moon.
However, this hypothesis would require conditions never deduced from the lunar samples: would require that the sample be formed at tremendous depths, in the lunar mantle, where very different rock compositions are planned.
So, it seems that the simplest interpretation is that of a sample coming from the Earth.
Source:
MAQ Magazine n. 11 / March - April 2019