PROGRESSES OF CONSORTIUM STUDIES FOR
HAYABUSA RETURNED SAMPLES: TROILITE AND
PHOSPHATE-BEARING PARTICLES.
Yuzuru Karouji1, Masayuki Uesugi1, Toru Yada1, Aiko Nakato1,
Kazuya Kumagai1, Tatsuaki Okada1,2, Masanao Abe1,2, 1Instituteof Space and Astronautical Science, Japan Aerospace Exploration
Agency (JAXA), E-mail: karouji@planeta.sci.isas.jaxa.jp, 2Lunarand Planetary Exploration Program Group, Japan Aerospace Exploration Agency (JAXA)
Introduction: As for the consortium studies started in 2013,
it is pushed forward by the Extraterrestrial Sample Curation
Team (ESCuTe) of JAXA leadership [e.g., 1-9]. The particles
used for the consortium studies are very interesting scientifically,
but is not distributed into international AO because they have rare
characteristics in composition, mineralogy, structure, or size. In
this paper, we report the progresses of these consortium studiesof particle mainly consisting of troilite and particles including
phosphates.
Particles mainly consisting of troilite: The particle, RAQD02-0245, consist mainly of FeS (~40 µm size). According toinitial description by SEM-EDS, olivine and pyroxene of around
10 µm size appeared embedded in main phase of FeS. X-ray CT
method was applied to this particle. As a result, the olivine andthe pyroxene were not embedded in FeS, but were small pieces
attached on FeS surface. Next step, the detailed observation ofthe particle surface by FESEM was done. By this observation, theeffect of the space weathering was not confirmed, but the shocktexture was observed on the surface.
As for this particle, analysis is going to be carried out as follows; (1) TEM observation of two samples sliced from the edgeof the particle by FIB observed for shock texture, and (3) applying of INAA to a remaining particle for chemical composition.
Particles including phosphates: Some particles in which
phosphate mineral might be included were found by our initialdescription. In order to study the history recorded in the phosphates, we propose the investigation of U-Pb systematics using
SIMS. We will perform the U-Pb dating of the phosphates as
many as possible and aim to understand the thermal history ofItokawa parent body such as crystallization age and the catastrophic collision if recorded.
X-ray CT method was applied to two particles, RB-CV-0025
and RB-QD04-0088. As a result of this observation, the threedimensional geometry of the phosphate minerals in these particles was confirmed. Now, particles were polished down to makethe phosphates appear on the surface. These phosphates will beanalyzed for U-Pb isotopes by SIMS.
References: [1] Karouji et al. (2013) 76th Annual Meeting of
the Meteritical Society, #5148, [2] Uesugi et al. (2013) 76th Annual Meeting of the Meteritical Society, #5146, [3] Yada et al.
(2013) 76th Annual Meeting of the Meteritical Society, #5150, [4]Karouji et al. (2013) Hayabusa Symposium 2013, #P202, [5] Karouji et al. (2013) Hayabusa Symposium 2013, #P203, [6] Uesugiet al. (2013) Hayabusa Symposium 2013, #P204, [7] Yada et al.
(2013) Hayabusa Symposium 2013, #P201, [8] Karouji et al.
(2014) 77th Annual Meeting of the Meteritical Society, #5240. [9]Uesugi et al. (2014) 77th Annual Meeting of the Meteritical Society, #5226.