Universities Space Research Association (USRA) January 24, 2019
Scientists may have discovered the oldest Earth rock ever—on the Moon. A lunar sample returned by the Apollo 14 astronauts may contain a bit of Earth from about 4 billion years ago. The research about this possible relic from the Hadean Earth is published today in the journal Earth and Planetary Science Letters.
An international team of scientists associated with the Center for Lunar Science and Exploration (CLSE), part of NASA’s Solar System Exploration Research Virtual Institute, found evidence that the rock was launched from Earth by a large impacting asteroid or comet. This impact jettisoned material through Earth’s primitive atmosphere, into space, where it collided with the surface of the Moon (which was three times closer to Earth than it is now) about 4 billion years ago. The rock was subsequently mixed with other lunar surface materials into one sample.
The team developed techniques for locating impactor fragments in the lunar regolith, which prompted CLSE Principal Investigator Dr. David A. Kring, a Universities Space Research Association (USRA) scientist at the Lunar and Planetary Institute (LPI), to challenge them to locate a piece of Earth on the Moon.
Led by Research Scientist Jeremy Bellucci and Professor Alexander Nemchin, team members working at the Swedish Museum of Natural History and Curtin University in Australia rose to the challenge. The result of their investigation is a 2 gram fragment of rock composed of quartz, feldspar, and zircon, all commonly found on Earth and highly unusual on the Moon. Chemical analysis of the rock fragment shows it crystallized in a terrestrial-like oxidized system, at terrestrial temperatures, rather than in the reducing and higher temperature conditions characteristic of the Moon.
Rock fragment from the Moon.
More:
https://solarsystem.nasa.gov/news/820/earths-oldest-rock-found-on-the-moon/
