An analysis of Northwest Africa (NWA) 16286, a lunar meteorite with a unique chemical signature, offers fresh insights into how the Moon’s interior evolved, highlighting the long-lived nature of its volcanic activity.
Backscattered electron image of the NWA 16286 sample. Image credit: Joshua Snape / University of Manchester.
Found in Africa in 2023, NWA 16286 is only one of 31 lunar basalts officially identified on Earth.
The 311-gram meteorite’s distinct composition, with melted glassy pockets and veins, suggests it was likely shocked by an asteroid or meteorite impact on the Moon’s surface before being ejected and eventually falling to Earth.
The new analysis by University of Manchester scientists lends weight to a theory that the Moon retained internal heat-generating processes that powered lunar volcanic activity in several distinct phases.
Lead isotope analysis dates the rock’s formation to around 2.35 billion years ago, during a period from which few lunar samples exist, making it the youngest basaltic lunar meteorite discovered on Earth.
Its rare geochemical profile sets it apart from those returned by previous Moon missions, with chemical evidence indicating it likely formed from a lava flow that solidified after emerging from deep within the Moon.
“Lunar rocks from sample return missions are fantastic in the insights they provide us, but they are limited to the immediate areas surrounding those mission landing sites,” said University of Manchester’s Dr. Joshua Snape.
“By contrast, lunar meteorites can potentially be ejected by impact cratering occurring anywhere on the Moon’s surface.”
“As such, there’s some serendipity surrounding this sample; it just happened to fall to Earth and reveals secrets about lunar geology without the massive expense 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 lead isotope composition of the rock — a geochemical fingerprint retained from when the rock formed — points to it originating from a source in the Moon’s interior with an unusually high uranium-to-lead ratio.
These chemical clues may help identify the mechanisms that have enabled periods of ongoing internal heat generation on the Moon.
“The age of the sample is especially interesting because it fills an almost billion-year gap in lunar volcanic history,” Dr. Snape said.
“It’s younger than the basalts collected by the Apollo, Luna and Chang’e 6 missions, but older than the much younger rocks brought back by China’s Chang’e 5 mission.”
“Its age and composition show that volcanic activity continued on the Moon throughout this timespan, and our analysis suggests an ongoing heat generation process within the Moon, potentially from radiogenic elements decaying and producing heat over a long period.
“Moon rocks are rare, so it’s always interesting when we get something that stands out and looks different to everything else.”
“This particular rock provides new constraints about when and how volcanic activity occurred on the Moon.”
“There is much more yet to learn about the Moon’s geological past, and with further analysis to pinpoint its origin on the surface, this rock will guide where to land future sample return missions.”
The researchers presented their results today at the Goldschmidt Conference 2025 in Prague, the Czech Republic.
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Joshua F. Snape et al. Northwest Africa 16286: investigating the age and origin of a new lunar mare basalt. Goldschmidt Conference 2025