The examination of North West Africa (NWA) 16286 reveals a lunar metstone with a distinctive chemical profile, offering new perspectives on the evolution of the moon’s interior and emphasizing the enduring nature of its volcanic activity.
Backscattered electron images of NWA 16286 samples. Image credit: Joshu Asu Nape/University of Manchester.
Discovered in Africa in 2023, NWA 16286 is one of only 31 moon basalts officially identified on Earth.
The distinct composition of the 311-gram metstone, featuring melted glassy pockets and veins, indicates it was likely impacted by an asteroid or metstone on the lunar surface before being ejected and eventually landing on Earth.
A recent study by researchers at the University of Manchester supports the theory that the moon has maintained internal heat production processes responsible for lunar volcanic activity across various stages.
Lead isotopic analyses suggest that these rock formations are the youngest basalt lunar metstones identified on Earth, dating back approximately 2.35 billion years, a time when lunar samples are scarce.
The sample’s unique geochemical profile distinguishes it from those brought back by previous lunar missions, indicating that its chemical characteristics likely result from lava flows that solidified after ascending from the moon’s depths.
“While the moon rocks returned from sample return missions provide valuable insights, they are limited to the immediate areas around those landing sites,” stated Dr. Joshua Snape from the University of Manchester.
“In contrast, this sample could originate from impact craters located anywhere on the moon’s surface.”
“Thus, there is a unique coincidence with this sample. It fortuitously landed on Earth, unveiling secrets about lunar geology without the need for an extensive space mission.”
The sample contains notably large crystals of olivine and is classified as olivine basalt, characterized by medium titanium levels and high potassium content.
Alongside the atypical age of the samples, researchers found that the lead isotopic composition of the rocks—geochemical signatures preserved when the rocks formed—originates from internal lunar sources with unusually high ratios of uranium and lead.
These chemical markers can assist in identifying the mechanisms behind the moon’s prolonged internal heat production.
“The sample’s age is particularly intriguing as it fills a billion-year gap in the history of lunar volcanism,” Dr. Snape noted.
“It is younger than the basalts collected during the Apollo, Luna, and Chang-E 6 missions, yet significantly older than the more recent rocks retrieved by the Chang-E 5 missions in China.”
“Its age and composition indicate that volcanic activity persisted throughout this entire timeframe, and our analysis suggests a potentially continuous process of heat generation from radioactive elements that generates heat over extended periods.
“Moon rocks are a rarity, making it always exciting to acquire samples that stand out from the norm.”
“This specific rock presents new constraints on the timing and nature of volcanic activity on the moon.”
“We still have much to learn about the lunar geological history. Further analyses to trace surface origins will inform where future sample return missions might be directed.”
The researchers presented their results today at the Goldschmidt Conference 2025 in Prague, Czech Republic.
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Joshua F. Snape et al. Northwest Africa 16286: An investigation into the age and origin of new moon basalts. Goldschmidt Conference 2025
Source: www.sci.news
