ACOMBINEDCATHODOLUMINESCENCEAND
MICRO-RAMAN STUDY OF PLAGIOCLASE FROMASTEROID ITOKAWA: AN IMPLICATION FOR STUDY
OF SPACE WEATHERING PROCESSES.
A. Gucsik1,2, H. Nishido3, K. Ninagawa4, C. Jäger5, M. Kayama6,
A. Kereszturi1, T. Nakamura7 and A. Tsuchiyama8. 1Konkoly
Thege Miklós Astronomical Institute, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences;
2Department of Geology, University of Johannesburg, Johannesburg, 2600 Auckland Park, South Africa, E-mail: argu1986@hotmail.com. 3Department of Biosphere-Geosphere
System Science, Okayama University of Science, 1-1 Ridai-cho,Okayama, 700-0005, Japan; 4Department of Applied Physics,Okayama University of Science, 1-1 Ridai-cho, Okayama, 7000005, Japan; 5Max Planck Institute for Astronomy, Helmholtzweg 3, Jena, D-07745, Germany; 6Department of Earth andPlanetary Sciences,Faculty of Science, Kobe University, 1-1
Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan; 7Department ofEarth and Planetary Materials Science, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan; 8Kyoto University, Faculty of Science, Graduate School of Science, Divisionof Earth and Planetary Sciences, Kitashirakawaoiwake-cho, Sakyu-ku, Kyoto-shi, 606-8502, Japan

Introduction: The purpose of this study is to clarify the nature aswell as degree of space weathering processes on surface ofasteroid Itokawa by using a multiple technological approach ofscanning electron microscope-cathodoluminescence (SEM-CL)and micro-Raman spectroscopy.
Samples and Experimental Procedure: Here, we report preliminary results of CL and Raman spectral investigation of two plagioclase particles RA-QD02-0025-01 (size: 51.8 µm) and RAQD02-0025-02 (size: 26 µm). SEM-CL (JEOL JSM 5410 LV)
spectral data were recorded by a photon counting method using aphotomultiplier tube (Hamamatsu: R2228) and converted to digital data. Further details of the CL equipment and analytical procedure can be found in Kayama et al. [1] and references therein.
Raman spectral measurements were carried out using a LabRam
Confocal Spectrometer (632 nm excitation) for the single spectrum at Max Planck Institute for Astronomy (Jena, Germany) andfor the Raman mapping by a WITec Alpha 300 spectrometer (532nm) at Department of Geology, University of Johannesburg(South Africa).
Results and Discussion: Cathodoluminescence spectral featuresof two plagioclase particles are centered at 2.83 eV (438 nm) and3.08 eV (402 nm). An emission at 438 nm is assigned to defectcenter, whereas the peak at 402 nm is related to Al-O-Al centeror Ti-center. However, it is important to note that most characteristic Mn-related activator peak for plagioclase is absent in both
samples [2]. Raman spectral features have peak positions at 485,
500 and 514 cm-1 (bending modes) [3], which are superimposedon relatively high background fluorescence. These observations
indicate that both particles have a highly disordered crystalline
structure, which would be occurred by a shock event or radiation
effect. However, further investigation must be done to classify
these processes.
References:[1] Kayama et al. 2011. Amer. Mineral., 96, 1238-1247.
[2] Götze et al. Am. Mineral., 84, 1027-1032. [3] Wang et al. J.
Raman Spectrosc. 35, 504-514.