Old and new minerals discovered in lunar samples brought back by China’s Chang’e 5 mission are helping scientists better understand the moon’s history.
In 2020, Chang’e 5 3.8 pounds (1.73 kg) of rock and dust returned from Oceanus Procellarum stormy sea), the largest dark region on the Moon, found at the western edge of the Moon. Analysis of these samples revealed a new mineral named changesite-(Y), the scientists reported in a paper published Wednesday (6 February).
Changesite (Y) is the sixth newly discovered lunar mineral discovered by researchers at the Beijing Institute of Uranium Geology (BRIUG).
related: China releases Chang’e 5 satellite samples to overseas researchers
moon are dotted with craters from asteroid The Moon has no atmosphere or geological activity, so it remains intact. The intense pressure and temperature from an asteroid impact changes the composition of the moon’s top layer of rock and dust, called regolith. Scientists are working to piece together the moon’s turbulent history.
Changesite (Y) must have formed in the aftermath of such an asteroid impact, creating a crater 1.9 miles to 20 miles (3 to 32 kilometers) wide, depending on the impact angle, according to estimates from computer models. may have been left behind.a Previous analysis The age of the moon rocks returned by Chang’e 5 has been determined to be 1.97 billion years.
The returned Chang’e 5 samples also contain a mixture of previously known silica minerals, particularly sifertite and stishovite. Scientists believe that these two minerals were likely deposited by the impact that formed Aristarchus crater. Aristarchus Crater is the youngest of the four impact craters that rained ejecta into the Oceanus Procellarum region visited by Chang’e 5.
Seifertite is known to transform into stishovite during high-pressure aftershocks of asteroid impacts, but much remains unknown about these minerals on the Moon.
“Although the moon’s surface is covered with tens of thousands of impact craters, the presence of high-pressure minerals in lunar samples is rare,” study co-author Wei Du of the Chinese Academy of Sciences said in the paper. Ta. statement. “One possible explanation for this is that most high-pressure minerals become unstable at high temperatures.”
Theoretically, sifertite and stishovite can only coexist at much higher pressures than the samples are thought to have witnessed, so their presence in the samples returned from Chang’e 5 is “inexplicable.” Scientists say it’s a combination of
In May of this year, China is scheduled to launch its next lunar exploration program. Chang’e 6will attempt to collect samples from the South Pole Aitken (SPA) Basin on the far side of the Moon.
For new research, paper It was published on Wednesday (February 6) in the journal Matter and Radiation at Extremes.