¹Takaaki Noguchi,^2,3Takahito Tominaga,^2,4Minako Takase,⁵Akira Yamaguchi,⁵Naoya Imae
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.14324]
¹Division of Earth and Planetary Science, Kyoto University, Kyoto, Japan
²Department of Earth and Planetary Science, Kyushu University, Fukuoka, Japan
³Kai Industries Co. Ltd., Gifu, Japan
⁴Fukuoka City Science Museum, Fukuoka, Japan
⁵National Institute of Polar Research, Japan, Tokyo, Japan
Published by arrangement with John Wiley & Sons

Over a period of 16 years, we collected Antarctic micrometeorites (AMMs) preserved in 1-t snow samples from the surface to a depth of ~10–15 cm near Dome Fuji Station, Antarctica. A total of 1025 AMMs were identified: 843 unmelted AMMs, 51 scoriaceous ones, and 131 cosmic spherules. Their average sizes were 40, 64, and 40 μm, respectively. The accretion rate of AMMs was inferred to be (3.3 ± 1.8) × 103 t year−1, based on the snow accumulation rate near Dome Fuji Station. We compared the Dome Fuji collection (DFC) with our previous Tottuki #5 collection (T5C) recovered from blue ice in 2000. Regardless of the collection methods, the full range size distributions of AMMs were well fitted by lognormal functions. In 2019 and 2020, we applied a freeze-drying (FD) system to collect AMMs. We identified 21 AMMs from 17 kg of surface snow. Both GEMS (glass with embedded metal and sulfide)-rich chondritic porous (CP) AMMs and hydrated fine-grained (H f-g) AMMs were identified. No detectable mineralogical differences were observed between a CP AMM from the DFC-FD and one from the DFC, suggesting that ~6 h of exposure to cold water (<8.7°C) did not affect the mineralogy of CP AMMs.