2.35-Billion-Year-Old Lunar Meteorite Fills One-Billion-Year Gap in Volcanic History of the Moon
An analysis of North West Africa (NWA) 16286, a lunar meteorite with a unique chemical signature, offers new information on the way in which the interior of the Moon has evolved, highlighting the nature with long service life of its volcanic activity.
Retroded electronic image of sample NWA 16286. Image credit: Joshua Snape / University of Manchester.
Found in Africa in 2023, NWA 16286 is only one of the 31 lunar basalts officially identified on Earth.
The distinct composition of the meteorite of 311 grams, with melted pockets and veins, suggests that it was probably shocked by an impact of asteroid or meteorite on the surface of the moon before being ejected and possibly falling on earth.
The new analysis of scientists at the University of Manchester lends weight to a theory that the Moon has preserved internal heat generating processes which fueled lunar volcanic activity in several distinct phases.
The analysis of the isotopes of lead dates from the formation of the rock to around 2.35 billion years, during a period of which few lunar samples exist, which makes it the youngest lunar meteorite discovery on earth.
Its rare geochemical profile distinguishes it from those returned by previous moon missions, with chemical evidence indicating that it probably formed from a flow of lava which has solidified after emerging from the deepest of the moon.
“The lunar rocks of the missions of return of the samples are fantastic in the ideas they provide us with, but they are limited to the immediate areas surrounding these mission landing sites,” said Dr. Joshua Snape from the University of Manchester.
“On the other hand, lunar meteorites can potentially be ejected by an impact that occurred anywhere on the surface of the Moon.”
“As such, there is a serendipity surrounding this sample; it just happened to fall on earth and reveals secrets on lunar geology without the massive expenses of a space mission.”
Containing relatively large crystals of mineral olivine, the rock is a type of lunar volcanic basalt called olivine phyric basalt. It contains moderate levels of titanium, high levels of potassium.
In addition to the unusual age of the sample, the authors found that the main isotopic composition of the rock – a geochemical imprint preserved from the moment the rock has formed – shows it from a source inside the moon with an unusually high uranium / auaddal ratio.
These chemical clues can help identify the mechanisms that have enabled continuous internal heat generation periods on the moon.
“The age of the sample is particularly interesting because it fills a gap of almost a billion years in the lunar volcanic history,” said Dr. Snape.
“It is younger than the basalts collected by the missions of Apollo, Luna and Chang’e 6, but older than the much younger rocks brought back by the China China 5 mission.”
“Its age and composition show that volcanic activity continued on the moon throughout this period, and our analysis suggests a process of generation of heat in progress in the Moon, potentially from decomposition radiogenic elements and by producing heat over a long period.
“The rocks of the moon are rare, so it’s always interesting when we get something that stands out and looks different from everything else.”
“This particular rock provides new constraints at the moment and the way in which volcanic activity has occurred on the moon.”
“There is still good to learn more about the geological past of the moon, and with a more in -depth analysis to identify its origin on the surface, this rock will guide where to land the future missions of return of samples.”
The researchers presented their results today at Goldschmidt 2025 conference In Prague, the Czech Republic.
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Joshua F. Snape and al. North West Africa 16286: investigate the age and origin of a new lunar basalt. Goldschmidt 2025 conference
