It’s been more than 50 years since the Apollo missions, and in that time, chemical analyses of the recovered lunar materials have revolutionized our understanding of planetary materials. One of the major findings as a result of this research is the recognition that the Moon is exceptionally depleted in particular volatile elements, and that these moon rocks also exhibit large chemical anomalies unlike anything seen on Earth.
In new research, authored by University of New Mexico graduate student Tony Gargano and scientists from UNM's Center for Stable Isotopes, in collaboration with scientists from NASA’s Johnson Space Center, published today in the Proceedings of the National Academy of Sciences (PNAS) titled Chlorine isotope composition and halogen contents of Apollo-return samples, researchers focused on chemical analyses of halogens, or the highly reactive elements F, Cl, Br, and I (fluorine, chlorine, bromine, and iodine) and found that lunar materials are exceptionally depleted in these elements, with unusually high amounts of the heavy form (stable isotope) of chlorine, which they explain as a result from the Moon-forming Giant Impact. The study of these volatile elements and isotopic systems helps scientists to better understand the chemical evolution of planets.
“When we are trying to understand how planets form and how life can be sustained on them, we’re concerned with retaining certain elements which are necessary for life such as hydrogen, or water – but we also know we need to lose some such as Cl which can be toxic to life at high concentrations.” Gargano continues, “The moon is a case study for how volatile elements are processed throughout planetary evolution - we have an abundant sample suite of rocks collected by the astronauts during the Apollo missions that allow us to test these ideas and processes.”
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Image via University of New Mexico.