Presentation on theme: "Cathodoluminescence spectral study of alkali feldspar and plagioclase in Yamato Martian nakhlite meteorites M. Kayama 1, A. Gucsik 2, N. Matsuda 3, H."— Presentation transcript:
Cathodoluminescence spectral study of alkali feldspar and plagioclase in Yamato Martian nakhlite meteorites M. Kayama 1, A. Gucsik 2, N. Matsuda 3, H. Nishido 1 and K. Ninagawa 4 1 Okayama Unversity of Science, RINS, Okayama, Japan 2 Max Planck Institute for Chemistry, Mainz, Germany 3 Okayama Unversity of Science, ISEI, Tottori, Japan 4 Okayama Unversity of Science, Dept. of Applied Physics, Okayama, Japan NIPR, Tokyo, 07 June 2007
Introduction 1. Detection and Observation of structural defects and impurity trace elements 2. Suggestion about crystal fields responsible for a structural configuration, which is altered by shock metamorphism evaluation of shock event in Y000749 CL measurement allows CL characterization of feldspar minerals in Y000749 and
Cathodoluminescence (CL) electron irradiation Micrograph of alkali feldspar 1 mm CL image of alkali feldspar
CL spectral measurements were performed on natural and experimentally shocked oligoclases (An19.7 single crystal shocked between 10.5 GPa and 45 GPa) and plagioclases from the equilibrated ordinary chondrites (Dar al Gani, Tenham) (Kaus and Bischoff, 2000).
In a pioneering study, Sippel and Spencer (1970) observed that the shock metamorphism caused peak shifts from green peak toward the red peak, peak broadening and decrease of luminescence intensity than in the undamaged counterpart in the CL spectra of shock-metamorphosed lunar feldspars. They noted that the distortions or disorder in the crystal field results in crystal field perturbations and these local variations occur broadened distribution of excited state energies due to shock metamorphism. Terrestrial plagioclase (An 85 ) Plagioclase from lunar crystalline rocks Plagioclase from lunar breccia Maskelynite
Literature Review:  Götze et al., (2000) in: M. Pagel, V.Barbin, P. Blanc, D. Ohnenstetter (Eds.) Cathodoluminescence in Geosciences, Springer, 245-270;  Petrov (1994) Amer. Miner. 79, 221-239;  Marshall (1988), Unwin Hyman, Boston. 146 pp;  Hayward (1998), in: L.J. Cabri, D.J. Vaughan (Eds.) Modern Approaches to Ore and Environmental Mineralogy, Mineralogical Association of Canada Short Course Series, 27, pp. 269-325;  Götze et al., (1999) Amer. Miner. 84, 1027-1032;  Sippel and Spencer (1970), Proc. Apollo 11 Lunar Sci.Conf. 3, 2413-2426;  Ramseyer et al., (1992), Tectonophysics 216, 195-204;  Kaus and Bischoff (2000), Meteoritics Planet. Sci. 35 A 86;  Boggs et al., (2001) Meteoritics Planet. Sci. 36, 783-793.
Peak position Yellow spectral peak Terrestrial Y000749 560 nm 575 nm Red spectral peak Terrestrial Y000749 750 nm 780 nm CL spectra of plagioclase
Conclusion CL emission peak of alkali feldspar and plagioclase in Y000749 differ from that of terrestrial analogues. UV spectral peak are not observed in CL spectra of plagioclase in Y000749 CL spectra of plagioclase in Y000749 show slight peak shift by comparing with experimentally shocked plagioclase at 20 GPa Impact pressure shocked on nakhlite is relatively low