Search

Your search keyword '"Hagiya, K"' showing total 216 results
Start Over Author "Hagiya, K"
216 results on '"Hagiya, K"'

1. Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Author

Nakamura, T., primary, Matsumoto, M., additional, Amano, K., additional, Enokido, Y., additional, Zolensky, M. E., additional, Mikouchi, T., additional, Genda, H., additional, Tanaka, S., additional, Zolotov, M. Y., additional, Kurosawa, K., additional, Wakita, S., additional, Hyodo, R., additional, Nagano, H., additional, Nakashima, D., additional, Takahashi, Y., additional, Fujioka, Y., additional, Kikuiri, M., additional, Kagawa, E., additional, Matsuoka, M., additional, Brearley, A. J., additional, Tsuchiyama, A., additional, Uesugi, M., additional, Matsuno, J., additional, Kimura, Y., additional, Sato, M., additional, Milliken, R. E., additional, Tatsumi, E., additional, Sugita, S., additional, Hiroi, T., additional, Kitazato, K., additional, Brownlee, D., additional, Joswiak, D. J., additional, Takahashi, M., additional, Ninomiya, K., additional, Takahashi, T., additional, Osawa, T., additional, Terada, K., additional, Brenker, F. E., additional, Tkalcec, B. J., additional, Vincze, L., additional, Brunetto, R., additional, Aléon-Toppani, A., additional, Chan, Q. H. S., additional, Roskosz, M., additional, Viennet, J.-C., additional, Beck, P., additional, Alp, E. E., additional, Michikami, T., additional, Nagaashi, Y., additional, Tsuji, T., additional, Ino, Y., additional, Martinez, J., additional, Han, J., additional, Dolocan, A., additional, Bodnar, R. J., additional, Tanaka, M., additional, Yoshida, H., additional, Sugiyama, K., additional, King, A. J., additional, Fukushi, K., additional, Suga, H., additional, Yamashita, S., additional, Kawai, T., additional, Inoue, K., additional, Nakato, A., additional, Noguchi, T., additional, Vilas, F., additional, Hendrix, A. R., additional, Jaramillo-Correa, C., additional, Domingue, D. L., additional, Dominguez, G., additional, Gainsforth, Z., additional, Engrand, C., additional, Duprat, J., additional, Russell, S. S., additional, Bonato, E., additional, Ma, C., additional, Kawamoto, T., additional, Wada, T., additional, Watanabe, S., additional, Endo, R., additional, Enju, S., additional, Riu, L., additional, Rubino, S., additional, Tack, P., additional, Takeshita, S., additional, Takeichi, Y., additional, Takeuchi, A., additional, Takigawa, A., additional, Takir, D., additional, Tanigaki, T., additional, Taniguchi, A., additional, Tsukamoto, K., additional, Yagi, T., additional, Yamada, S., additional, Yamamoto, K., additional, Yamashita, Y., additional, Yasutake, M., additional, Uesugi, K., additional, Umegaki, I., additional, Chiu, I., additional, Ishizaki, T., additional, Okumura, S., additional, Palomba, E., additional, Pilorget, C., additional, Potin, S. M., additional, Alasli, A., additional, Anada, S., additional, Araki, Y., additional, Sakatani, N., additional, Schultz, C., additional, Sekizawa, O., additional, Sitzman, S. D., additional, Sugiura, K., additional, Sun, M., additional, Dartois, E., additional, De Pauw, E., additional, Dionnet, Z., additional, Djouadi, Z., additional, Falkenberg, G., additional, Fujita, R., additional, Fukuma, T., additional, Gearba, I. R., additional, Hagiya, K., additional, Hu, M. Y., additional, Kato, T., additional, Kawamura, T., additional, Kimura, M., additional, Kubo, M. K., additional, Langenhorst, F., additional, Lantz, C., additional, Lavina, B., additional, Lindner, M., additional, Zhao, J., additional, Vekemans, B., additional, Baklouti, D., additional, Bazi, B., additional, Borondics, F., additional, Nagasawa, S., additional, Nishiyama, G., additional, Nitta, K., additional, Mathurin, J., additional, Matsumoto, T., additional, Mitsukawa, I., additional, Miura, H., additional, Miyake, A., additional, Miyake, Y., additional, Yurimoto, H., additional, Okazaki, R., additional, Yabuta, H., additional, Naraoka, H., additional, Sakamoto, K., additional, Tachibana, S., additional, Connolly, H. C., additional, Lauretta, D. S., additional, Yoshitake, M., additional, Yoshikawa, M., additional, Yoshikawa, K., additional, Yoshihara, K., additional, Yokota, Y., additional, Yogata, K., additional, Yano, H., additional, Yamamoto, Y., additional, Yamamoto, D., additional, Yamada, M., additional, Yamada, T., additional, Yada, T., additional, Wada, K., additional, Usui, T., additional, Tsukizaki, R., additional, Terui, F., additional, Takeuchi, H., additional, Takei, Y., additional, Iwamae, A., additional, Soejima, H., additional, Shirai, K., additional, Shimaki, Y., additional, Senshu, H., additional, Sawada, H., additional, Saiki, T., additional, Ozaki, M., additional, Ono, G., additional, Okada, T., additional, Ogawa, N., additional, Ogawa, K., additional, Noguchi, R., additional, Noda, H., additional, Nishimura, M., additional, Namiki, N., additional, Nakazawa, S., additional, Morota, T., additional, Miyazaki, A., additional, Miura, A., additional, Mimasu, Y., additional, Matsumoto, K., additional, Kumagai, K., additional, Kouyama, T., additional, Kikuchi, S., additional, Kawahara, K., additional, Kameda, S., additional, Iwata, T., additional, Ishihara, Y., additional, Ishiguro, M., additional, Ikeda, H., additional, Hosoda, S., additional, Honda, R., additional, Honda, C., additional, Hitomi, Y., additional, Hirata, N., additional, Hayashi, T., additional, Hayakawa, M., additional, Hatakeda, K., additional, Furuya, S., additional, Fukai, R., additional, Fujii, A., additional, Cho, Y., additional, Arakawa, M., additional, Abe, M., additional, and Tsuda, Y., additional

Published
2023
Full Text
View/download PDF

4. Oriented Mineral Transformation in a Dark Inclusion from the Leoville Meteorite

Author

Buchanan, P. C, Zolensky, M. E, Weisberg, M. K, Hagiya, K, Mikouchi, T, Takenouchi, A, Hasegawa, H, Ono, H, Higashi, K, and Ohsumi, K

Subjects
Geosciences (General), Lunar And Planetary Science And Exploration
Abstract

Dark inclusions (DIs) in chondrites and achondrites are dark gray to black fragments that include a wide variety of materials that have experienced very different petrologic histories. Based on the law of inclusions, they are rocks that accreted prior to and are older than their host meteorites and possibly rep-resent an earlier generation of material. The origin of these inclusions and their relationship to their host meteorites is not always clear. They are interesting in that they represent lithologies that experienced different parent body histories than their host meteorites and are either exotic components or originated from different regions of the meteorite parent body. In many cases, DIs in CV chondrites have been altered to greater degrees than their host meteorites suggesting pre accretionary alteration [e.g., 1,2,3]. There is debate concerning whether or not these DIs record an earlier era of aqueous alteration and subsequent thermal metamorphism, and how these processes may have also affected the host CV materials. The present study is a description of a dark inclusion found in the Leoville meteorite (specifically, thin section USNM 3535-1). This inclusion has some interesting features that have considerable relevance for this discussion.

Published
2017

5. Crystallographic Study of Itokawa Particle, RA-QD02-0127 by Using Energy-Scanning X-Ray Diffraction Method with Synchrotron Radiation

Author

Hagiya, K, Ohsumi, K, Komatsu, M, Mikouchi, T, Zolensky, M. E, Hirata, A, Yamaguchi, S, and Kurokawa, A

Subjects
Lunar And Planetary Science And Exploration
Abstract

The petrographic study of Itokawa particle, RA-QD02-0127 has been performed by SEM-EDS and optical microscope observations. The purpose of this study is to understand better the metamorphic and impact shock history of asteroid Itokawa, and other S-class asteroids.

Published
2016

6. Ceres Revealed in a Grain of Salt

Author

Zolensky, M. E, Bodnar, R. J, Fries, M, Chan, Q. H.-S, Kebukawa, Y, Mikouchi, T, Hagiya, K, Komatsu, M, Ohsumi, K, and Steele, A

Subjects
Lunar And Planetary Science And Exploration
Abstract

Introduction: Zag and Monahans (1998) are H chondrite regolith breccias containing 4.5 giga-year-old halite crystals which contain abundant inclusions of aqueous fluids, solids and organics. These all originated on a cryo-volcanically-active C class asteroid, probably 1 Ceres; the halite was transported to the regolith of the H chondrite parent asteroid, potentially 6 Hebe. Detailed analysis of these solids will thus potentially reveal the mineralogy of Ceres. Mineralogy of solids in the Monahans Halite Solid grains are present in the halites, which were entrained within the mother brines during eruption, including material from the interior and surface of the erupting body. The solids include abundant, widely variable organics that could not have been significantly heated (which would have resulted in the loss of fluids from the halite). Our analyses by Raman microprobe, SEM/EDX, synchrotron X-ray diffraction, UPLC-FD/QToF-MS, C-XANES and TEM reveal that these trapped grains include macromolecular carbon (MMC) similar in structure to CV3 chondrite matrix carbon, aliphatic carbon compounds, olivine (Fo99-59), high- and low-Ca pyroxene, feldspars, phyllosilicates, magnetite, sulfides, metal, lepidocrocite, carbonates, diamond, apatite and zeolites. Conclusions: The halite in Monahans and Zag derive from a water and carbon-rich object that was cryo-volcanically active in the early solar system, probably Ceres. The Dawn spacecraft found that Ceres includes C chondrite materials. Our samples include both protolith and aqueously-altered samples of the body, permitting understanding of alteration conditions. Whatever the halite parent body, it was rich in a wide variety of organics and warm, liquid water at the solar system's dawn.

Published
2016

7. Synchrotron Radiation XRD Analysis of Indialite in Y-82094 Ungrouped Carbonaceous Chondrite

Author

Mikouchi, T, Hagiya, K, Sawa, N, Kimura, M, Ohsumi, K, Komatsu, M, and Zolensky, M

Subjects
Astrophysics, Instrumentation And Photography
Abstract

Y-82094 is an ungrouped type 3.2 carbonaceous chondrite, with abundant chondrules making 78 vol.% of the rock. Among these chondrules, an unusual porphyritic Al-rich magnesian chondrule is reported that consists of a cordierite-like phase, Al-rich orthopyroxene, cristobalite, and spinel surrounded by an anorthitic mesostasis. The reported chemical formula of the cordierite-like phase is Na(0.19)Mg(1.95)Fe(0.02)Al(3.66)Si(5.19)O18, which is close to stoichiometric cordierite (Mg2Al3[AlSi5O18]). Although cordierite can be present in Al-rich chondrules, it has a high temperature polymorph (indialite) and it is therefore necessary to determine whether it is cordierite or indialite in order to better constrain its formation conditions. In this abstract we report on our synchrotron radiation X-ray diffraction (SR-XRD) study of the cordierite-like phase in Y-82094.

Published
2016

8. Petrology of Two Itokawa Particles: Comparison with Equilibrated LL Chondrites

Author

Komatsu, M, Mikouchi, T, Arai, T, Fagan, T. J, Zolensky, M, Hagiya, K, Ohsumi, K, and Karouji, Y

Subjects
Lunar And Planetary Science And Exploration
Abstract

A strong link between Itokawa particles and LL chondrites was confirmed by preliminary examinations of Hayabusa particles [e.g., 1, 2]. Both poorly equilibrated and highly equilibrated particles have been found among the grains returned from Itokawa [1], and it is suggested that they correspond to LL4 and LL5-6, respectively. Here we report the petrography of two Itokawa particles and TEM study of one, and compare them to Antarctic LL chondrites with variable petrologic types (LL4-LL7) in order to understand the metamorphic history of asteroid Itokawa.

Published
2015

10. Minerology and Crystallography of Some Itokawa Particles Returned by the Hayabusa Mission

Author

Mikouchi, T, Komatsu, M, Hagiya, K, Ohsumi, K, Zolensky, M, Hoffmann, V, Martinez, J, Hochleitner, R, Kaliwoda, M, Terada, Y, Yagi, N, Takata, M, Satake, W, Aoyagi, Y, Takenouchi, A, Yada, T, Karouji, Y, Uesugi, M, and Miyamoto, M

Subjects
Lunar And Planetary Science And Exploration
Abstract

JAXA Hayabusa mission success-fully returned particles of the asteroid Itokawa to the earth in 2010. The recovered particles were carefully studied by the preliminary examination (PE) team and the obtained results are providing significant and unique information about the formation and evolution of meteorite parent bodies [1-6]. These particles further revealed that their mineral compositions and oxygen isotopes are close to those of equilibrated LL chon-drites [1,2], which matches with the observation at the orbit [7]. After the PE, JAXA distributed the samples as international AO study and we received 4 new and 3 PE particles. The new samples may contain some exot-ic components that have not been found by the PE study, and are of special interest. We have performed a detailed mineralogical and crystallographic study on these particles and here report the results.

Published
2014

12. Sex-related differences in clinical features and in-hospital outcomes of acute aortic dissection type b

Author

Takahashi, T, primary, Yoshino, H, additional, Akutsu, K, additional, Shimokawa, T, additional, Ogino, H, additional, Kunihara, T, additional, Usui, M, additional, Watanabe, K, additional, Kawata, M, additional, Masuhara, H, additional, Yamasaki, M, additional, Hagiya, K, additional, Yamamoto, T, additional, Nagao, K, additional, and Takayama, M, additional

Published
2020
Full Text
View/download PDF

14. Diagnostic markers for discriminating between acute aortic dissection and acute myocardial infarction during the pre-hospital phase: analysis of 3,195 cases

Author

Watanabe, K, primary, Yoshino, H, additional, Takahashi, T, additional, Usui, M, additional, Akutsu, K, additional, Shimokawa, T, additional, Kunihara, T, additional, Kawata, M, additional, Masuhara, H, additional, Ogino, H, additional, Yamasaki, M, additional, Hagiya, K, additional, Yamamoto, T, additional, Nagao, K, additional, and Takayama, M, additional

Published
2020
Full Text
View/download PDF

18. Early Solar System Cryovolcanics in the Laboratory

Author

Zolensky, M, Fries, M, Bodnar, R, Yurimoto, H, Itoh, S, Steele, A, Mikouchi, T, Hagiya, K, Ohsumi, K, Le, L, and Rahman, Z

Subjects
Geophysics
Abstract

Two thermally-metamorphosed ordinary chondrite regolith breccias, Monahans 1998 (H5) and Zag (H3-6) contain fluid inclusion-bearing halite (NaCl) crystals, dated by K-Ar, Rb-Sr and I-Xe systematics to be approx. 4.5 billion years old. Heating/freezing studies of the aqueous fluid inclusions demonstrated that they were trapped near 25 C, and their continued presence in the halite grains requires that their incorporation into the H chondrite asteroid was post metamorphism.

Published
2013

19. The Nature of C Asteroid Regolith from Meteorite Observations

Author

Zolensky, M, Mikouchi, T, Hagiya, K, Ohsumi, K, Komatsu, M, Jenniskens, P, Le, L, Yin, Q.-Z, Kebukawa, Y, and Fries, M

Subjects
Geophysics
Abstract

Regolith from C (and related) asteroid bodies are a focus of the current missions Dawn at Ceres, Hayabusa 2 and OSIRIS REx. An asteroid as large as Ceres is expected to be covered by a mature regolith, and as Hayabusa demonstrated, flat and therefore engineeringly-safe ponded deposits will probably be the sampling sites for both Hayabusa 2 and OSIRIS REx. Here we examine what we have learned about the mineralogy of fine-grained asteroid regolith from recent meteorite studies and the examination of the samples harvested from asteroid Itokawa by Hayabusa.

Published
2013

20. A CAI in the Ivuna CI1 Chondrite

Author

Frank, David R, Zolensky, M, Martinez, J, Mikouchi, T, Ohsumi, K, Hagiya, K, Satake, W, Le, L, Ross, D, and Peslier, A

Subjects
Geophysics
Abstract

We have recently discovered the first well-preserved calcium aluminum-rich inclusion (CAI) in a CI1 chondrite (Ivuna). Previously, all CI1 chondrites were thought to be devoid of preserved CAI and chondrules due to the near total aqueous alteration to which their parent body (bodies) have been subjected. The CAI is roughly spherical, but with a slight teardrop geometry and a maximum diameter of 170 microns (fig. 1). It lacks any Wark-Lovering Rim. Incipient aqueous alteration, and probably shock, have rendered large portions of the CAI poorly crystalline. It is extremely fine-grained, with only a few grains exceeding 10 microns. We have performed electron microprobe analyses (EPMA), FEG-SEM imaging and element mapping, as well as electron back-scattered diffraction (EBSD) and synchrotron X-ray diffraction (SXRD) in order to determine the fundamental characteristics of this apparently unique object.

Published
2011

21. Olivine in Almahata Sitta - Curiouser and Curiouser

Author

Zolensky, M. E, Herrin, J, Mikouchi, T, Satake, W, Kurihara, T, Sandford, S. A, Milam, S. N, Hagiya, K, Ohsumi, K, Friedrich, J. M, Jeniskens, P, Shaddad, M. H, Le, L, and Robinson, G. A

Subjects
Lunar And Planetary Science And Exploration
Abstract

Almahata Sitta (hereafter Alma) is an anomalous, polymict ureilite. Anomalous features include low abundance of olivine, large compositional range of silicates, high abundance and large size of pores, crystalline pore wall linings, and overall finegrained texture. Tomography suggests the presence of foliation, which is known from other ureilites. Alma pyroxenes and their interpretation are discussed in two companion abstracts. In this abstract we discuss the composition of olivine in Alma, which is indicative of the complexity of this meteorite.

Published
2010

22. Mineralogy of Pyroxene and Olivine in the Almahata Sitta Ureilite

Author

Mikouchi, T, Zolensky, M, Takeda, H, Hagiya, K, Ohsumi, K, Satake, W, Kurihara, T, Dept. of Physics, and Shaddad, M. H

Subjects
Geophysics
Abstract

The Almahata Sitta meteorite (hereafter "Alma") is the first example of a recovered asteroidal sample that fell to earth after detection still in the orbit (2008TC3 asteroid), and thus is critical to understand the relationship between meteorites and their asteroidal parent bodies [1]. Alma is a polymict ureilite showing a fine-grained brecciated texture with variable lithologies from black, porous to denser, white stones [1]. It is an anomalous ureilite because of wide compositional ranges of silicates with abundant pores often coated by vapor-deposit crystals [1]. Nevertheless, Alma has general similarities to all ureilites because of reduction textures of silicates suggestive of rapid cooling from high temperature as well as heterogeneous oxygen isotope compositions [e.g., 1-5]. Alma is especially unique because it spans the compositional range of known ureilites [1]. In this abstract we report detailed mineralogical and crystallographic investigations of two different fragments to further constrain its thermal history with regards to the nature of the ureilite parent body.

Published
2010

24. X-Ray Diffraction Study of L2005 AG17 (IDPs) by Using SR

Author

Ohsumi, K. O, Hagiya, K. H, and Zolensky, M. E

Subjects
Lunar And Planetary Science And Exploration
Abstract

X-ray diffraction study revealed the existence of magnetite and new type of pyrrhotite with the chemical formula of Fe0.56S in L2005 AG17. Considering the total chemical formula of Fe0.83S, residual iron in amorphous state might exist in this sample. Additional information is contained in the original extended abstract.

Published
2002

27. A nationwide survey of intravenous antimicrobial use in intensive care units in Japan

Author

Ohnuma, Tetsu, primary, Hayashi, Yoshiro, additional, Yamashita, Kazuto, additional, Marquess, John, additional, Lefor, Alan Kawarai, additional, Sanui, Masamitsu, additional, Andoh, K., additional, Egi, M., additional, Fujita, M., additional, Fujitani, S., additional, Gushima, Y., additional, Hagiya, K., additional, Hagiya, H., additional, Ide, T., additional, Iizuka, Y., additional, Ohnuma, T., additional, Itagaki, T., additional, Ito, T., additional, Ito, M., additional, Iwashita, Y., additional, Izawa, J., additional, Izuta, S., additional, Kabutan, K., additional, Kamochi, M., additional, Kashiura, M., additional, Matsuo, K., additional, Matsushima, H., additional, Miyazaki, D., additional, Miyazu, M., additional, Nagata, I., additional, Takei, T., additional, Nagatani, H., additional, Nakagawa, M., additional, Nakane, M., additional, Nishi, K., additional, Noguchi, M., additional, Nomura, T., additional, Nunomiya, S., additional, Obayashi, T., additional, Oda, T., additional, Oe, K., additional, Ota, K., additional, Saito, N., additional, Sako, S., additional, Sekino, M., additional, Seo, R., additional, Shiino, Y., additional, Shime, N., additional, Shimizu, K., additional, Takada, K., additional, Takimoto, K., additional, Taneda, M., additional, Uehara, K., additional, Unemoto, K., additional, Yamada, T., additional, and Yasuda, H., additional

Published
2018
Full Text
View/download PDF

32. Lactation Persistency as a Component Trait of the Selection Index and Increase in Reliability by Using Single Nucleotide Polymorphism in Net Merit Defined as the First Five Lactation Milk Yields and Herd Life

Author

Togashi, K., primary, Hagiya, K., additional, Osawa, T., additional, Nakanishi, T., additional, Yamazaki, T., additional, Nagamine, Y., additional, Lin, C. Y., additional, Matsumoto, S., additional, Aihara, M., additional, and Hayasaka, K., additional

Published
2012
Full Text
View/download PDF

37. OLIVINE MINERALOGY OF ASTEROID RYUGU SAMPLES AND CI CHONDRITES: FURTHER EVIDENCE FOR THEIR COMMON ORIGIN.

Author

Mikouchi, T., Yoshida, H., Nakamura, T., Zolensky, M. E., Nakashima, D., Hagiya, K., Kikuiri, M., Morita, T., Amano, K., Kagawa, E., Yurimoto, H., Noguchi, T., Okazaki, R., Yabuta, H., Naraoka, H., Sakamoto, K., Tachibana, S., Watanabe, S., and Tsuda, Y.

Subjects
OLIVINE, CHONDRITES, MINERALOGY, ASTEROIDS, PHYLLOSILICATES, BRECCIA
Abstract

Introduction: Initial analysis of asteroid Ryugu samples has revealed that they were mm-μm scale breccia mostly composed of aqueously altered phases (e.g., Mg-Fe phyllosilicates, carbonates) and showed remarkable similarities to CI chondrites in mineralogy and chemistry [e.g., 1,2]. Our detailed analysis of Ryugu samples has detected small amounts (<<1 vol.%) of unaltered silicates that would escape severe aqueous alteration [3]. Olivine is the most abundant (>90 vol%) phase among such unaltered silicates. Although most Ryugu olivine grains are smaller than 5 μm, they bear important information about the precursors of the parent Ryugu asteroid. In this abstract we report additional results of olivine mineralogical study of Ryugu samples, and especially compare with olivine grains in CI chondrites (Ivuna and Orgueil) to further discuss their relationship and possible common origin. Samples and Methods: Polished sections of A0026, A0055, A0063, A0106, C0002, C0023, C0025, C0033, C0040, C0046, C0055, C0076 and C0103 were analyzed using JEOL JXA-8530F FE-EPMA at Univ. of Tokyo. The quantitative analysis was performed at 12 kV accelerating voltage / 30 nA beam current (counting times at peaks: 30 sec), allowing us to obtain accurate compositions even from ~1 μm olivine grain. For comparison, polished sections of Ivuna and Orgueil with similar size to Ryugu samples (a few mm in size) were analyzed by the same method. Results: Olivine grains are present only in weakly-altered lithologies in Ryugu samples [e.g., 2]. So far we have not found olivine from Chamber A samples. Although we acquired compositions from ~200 additional olivine grains this time, the obtained compositions are basically identical to what we have already obtained [3]. Olivine compositions are clustered at Fo99 and extends to Fo44. Most olivine has 0.0-0.7 wt% MnO, and rare (<5%) LIME olivine (MnO/FeO>1 in wt%) grains are present. There is a positive correlation between Mn and Cr in olivine (MnO: 0.0-1.5 wt% vs. Cr2O3: 0.0-0.7 wt%) (Fig. 1). Most olivine grains are Ca-poor (CaO: <0.1 wt%). The comparative analysis of Ivuna and Orgueil has shown that both samples are similarly brecciated to Ryugu samples in size and mineralogy, and we found that weakly-altered lithologies contain tiny (mostly <5 μm) olivine grains. The size, texture, abundance and mineral compositions of olivine in Ivuna and Orgueil are strikingly similar to those of Ryugu olivines both in major and minor elemental compositions (Fig. 1). Discussion and Conclusion: We found identical olivine mineralogy between Ryugu samples and CI chondrites, further supporting that Ryugu samples are similar to CI chondrites [e.g., 1,2]. Although olivine has been reported in CI chondrites, the reported size is larger than 50 μm in many cases [e.g., 4]. Smaller olivine grains (<5 μm) as found in this study have not been well documented except few cases [e.g., 5]. Because the reported CI olivine composition is slightly different from our CI chondrite data [e.g., 4], there would be multiple origins for olivine in CI chondrites and Ryugu samples. In any case, the presence of small olivine grains (<5 μm) found in Ryugu and CI chondrites is important because such tiny olivine could be common precursors of these chondritic materials. [ABSTRACT FROM AUTHOR]

Published
2022

Catalog

Books, media, physical & digital resources
See catalog results