AsianScientist (Jun. 26, 2018) – A team of Japanese scientists has discovered a mineral known as moganite in a lunar meteorite found in northwest Africa. This is significant because moganite is a mineral that requires water to form, reinforcing the belief that water exists on the Moon. Their findings are published in Science Advances.
In recent years, space missions have found evidence of lunar water or ice concentrated at the poles of the Moon where sunlight appears at a very narrow angle, leading to pockets of cold traps. However, in this study led by Assistant Professor Masahiro Kayama of Tohoku University’s Frontier Research Institute for Interdisciplinary Sciences, Japan, scientists have found evidence of abundant water ice in the lunar subsurface at mid and lower latitudes.
Kayama and his team analyzed 13 lunar meteorites using sophisticated methods to determine the chemical compositions and structures of their minerals. These methods included electron microscopy and micro-Raman spectroscopy to determine the structure of the minerals based on their atomic vibration. Moganite was found in only one of those 13 samples, confirming the team’s theory that it could not have formed in the African desert.
“If terrestrial weathering had produced moganite in the lunar meteorite, there should be moganite present in all the samples that fell to Earth around the same time. But this was not the case,” said Kayama.
He added that part of the moganite had changed into the high-pressure silica (SiO2) minerals stishovite and coesite, which he believes were most likely formed through heavy impact collisions on the Moon.
The researchers noted that the meteorites probably came from an area of the Moon called the Procellarum Terrane, and that the moganite was formed through the process of water evaporation in strong sunlight. Kayama’s working theory is that deeper under the lunar surface, protected from the sun, crystals of water ice could be abundant.
“Moganite is a crystal of silicon dioxide and is similar to quartz. It forms on Earth as a precipitate when alkaline water including SiO2 is evaporated under high pressure conditions,” said Kayama. “The existence of moganite strongly implies that there is water activity on the Moon.”
The article can be found at: Kayama et al. (2018) Discovery of Moganite in a Lunar Meteorite as a Trace of H2o Ice in the Moon’s Regolith.
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Source: Tohoku University; Photo: Masahiro Kayama.
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