Discovery of mogánite in a lunar meteorite as a trace of H2O ice in the Moon’s regolith

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Marco E. Ciriotti
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Discovery of mogánite in a lunar meteorite as a trace of H2O ice in the Moon’s regolith

Messaggio da Marco E. Ciriotti » sab 05 mag, 2018 11:12

Referenza:
▪ Kayama, M., Tomioka, N., Ohtani, E., Seto, Y., Nagaoka, H., Götze, J., Miyake, A., Ozawa, S., Sekine, T., Miyhara, M., Tomeoka, K., Matsumoto, M., Shoda, N., Hirao, N., Kobayashi, T. (2018): Discovery of moganite in a lunar meteorite as a trace of H2O ice in the Moon’s regolith. Science Advances, 4, eaar4378; DOI: 10.1126/sciadv.aar4378.

Abstract:
Moganite, a monoclinic SiO2 phase, has been discovered in a lunar meteorite. Silica micrograins occur as nanocrystalline aggregates of mostly moganite and occasionally coesite and stishovite in the KREEP (high potassium, rare-earth element, and phosphorus)–like gabbroic-basaltic breccia NWA 2727, although these grains are seemingly absent in other lunar meteorites. We interpret the origin of these grains as follows: alkaline water delivery to the Moon via carbonaceous chondrite collisions, fluid capture during impact-induced brecciation, moganite precipitation from the captured H2O at pH 9.5 to 10.5 and 363 to 399 K on the sunlit surface, and meteorite launch from the Moon caused by an impact at 8 to 22 GPa and >673 K. On the subsurface, this captured H2O may still remain as ice at estimated bulk content of >0.6 weight %. This indicates the possibility of the presence of abundant available water resources underneath local sites of the host bodies within the Procellarum KREEP and South Pole Aitken terranes.


NdR: Open access: http://advances.sciencemag.org/content/ ... r4378.full
Il nome esatto è mogánite (accento acuto sulla a).
Marco E. Ciriotti

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