Lunar mineral turns up in Oz
Tranquillityite spotted in WA rocks
Until now, the mineral tranquillityite – consisting of iron, zirconium, yttrium, titanium, silicon and oxygen, and almost completely useless – has only been observed in rocks brought back from the glory days of the moon landings. Now, a team of scientists in Western Australia has found it for the first time in Earthbound samples.
Of the three minerals first observed in lunar basalts collected by Apollo astronauts, only tranquillityite had not since been spotted on Earth; armalcolite and pyroxferroite both turned up within around a decade of the moon landings.
The Curtin University / University of Western Australia team searched igneous rocks in that state, seeking out samples that hadn’t undergone large-scale metamorphic changes because tranquillityite is easily transformed into other minerals by heat and pressure.
The reddish-brown tranquillityite was discovered in rocks found at the Eel Creek Formation in the north-eastern Pilbara Craton – in other words, a long way from anywhere – where rocks from Archean Earth (more than 2.5 billion years old) can be found.
Electron scanning with an ion microscope was used to identify the distinctive scattering patterns tranquillityite produces, according to Science Now.
While economically useless, the researchers (Birger Rasmussen and Courtney Gregory of Curtin University, Janet Muhling and Alexandra Suvorova of the University of Western Australia) believe tranquillityite will be useful in helping to determine the age of other rocks.
“Where sufficiently coarse, it represents an exceptional new U-Pb geochronometer,” they note in the abstract of their paper published in Geology.
Given how many real moon rocks have been lost by NASA, it can only be a matter of time before frauds and fakers start dying in the Pilbara while looking for their own tranquillityite samples to pass off as the real thing. ®
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