Science & Technology, Canada (Commonwealth Union) – A recent study conducted by a postdoctoral fellow from a Western University challenge previously held beliefs about the early lunar crust. Contrary to existing understanding, the research reveals that the lunar surface, composed of the early crust, was significantly enriched in water over 4 billion years ago. This groundbreaking discovery, detailed in a study published in the prestigious journal Nature Astronomy, sheds new light on the history of the Moon.
Tara Hayden, who conducted the research as a graduate student at The Open University (U.K.), worked with a Moon-originating meteorite she had classified. In a notable first, Hayden identified the presence of apatite, the most common phosphate mineral, in a sample of the early lunar crust.
This finding introduces compelling evidence that challenges the previous assumption about the scarcity of water in the Moon’s early crust. It paves the way for a deeper exploration of lunar history, offering fresh perspectives on the composition and conditions of the Moon during its formative years.
Hayden, now a cosmochemist collaborating with renowned planetary geologist Gordon “Oz” Osinski in Western’s Department of Earth Sciences, expressed her excitement about the discovery. She emphasized the significance of the identification of apatite in the early lunar crust, describing it as a pivotal step in unraveling the mysteries of this previously unknown phase in lunar history. The study indicates that the Moon’s early crust was more water-rich than initially presumed, and the stable isotopes of its volatiles hint at a more intricate history than previously understood.
Hayden says “Lunar meteorites are revealing new, exciting parts of the Moon’s evolution and expanding our knowledge beyond the samples collected during the Apollo missions. As the new stage of lunar exploration begins, I am eager to see what we will learn from the lunar far side.”
Initially, the Apollo samples were believed to be lacking in volatile compounds when they were brought back from the Moon, contributing to the widespread characterization of the Moon as ‘bone dry.’
However, in 2008, researchers led by Alberto Saal made a groundbreaking discovery of substantial amounts of water and other volatiles in glass beads extracted from the Apollo sample collection. This revelation triggered a fifteen-year period of re-examining the Apollo samples, and concurrently, newly discovered lunar meteorites disclosed the presence of considerably more water distributed across the lunar surface.
Hayden, a researcher, highlighted the significance of the Apollo samples in understanding the Moon’s water history, acknowledging that these samples represent only about five percent of the entire lunar surface. She emphasized the importance of obtaining more samples through the upcoming Artemis missions, as the current alternative sources are limited to meteorites from the Moon’s surface.
Hayden made her own discovery during her PhD studies at The Open University while examining a rock sample from a lunar meteorite for a collector. Beyond its initial identification, the sample turned out to contain crucial data about the presence of water on the Moon.
“I was so lucky the meteorite not only came from the Moon but remarkably, featured chemistry so vital to our understanding about lunar water-bearing minerals,” She added.
According to the researchers of the study these findings primarily concentrated on the mineral apatite, known for housing volatile elements in its mineral structure. Apatite was identified in all lunar rock types except for glass beads and ferroan anorthosites, the latter representing the Moon’s early crust. The Ferroan Anorthosite group, with an age ranging from 4.5 to 4.3 billion years, stands out as exceptionally ancient and is the sole rock type documented to have originated directly from the Lunar Magma Ocean—an era when the Moon existed in a nearly entirely molten state.
