180 likes | 300 Views
Cathodoluminescence and Raman spectroscopic study of maskelynite in shergottite (Dhofar 019) and experimentally shocked plagioclase. M. Kayama, T. Nakazato, H. Nishido, K. Ninagawa, A. Gucsik, and Sz. B é rczi. Introduction. Dhofar 019 : olivine-bearing basaltic shergottite.
E N D
Cathodoluminescence and Raman spectroscopic study of maskelynite in shergottite (Dhofar 019) and experimentally shocked plagioclase M. Kayama, T. Nakazato, H. Nishido, K. Ninagawa, A. Gucsik, and Sz. Bérczi
Introduction Dhofar 019 : olivine-bearing basaltic shergottite Badjukov D. D et al. (2001) Taylor L. A et al (2002) Dhofar 019 shocked in the range of 30-35 GPa judging from the formation of maskelynite Qualitative estimation of shocked pressure
In this study CL and Raman measurement have been carried out on 1. Experimentally shocked plagioclase to characterize their CL behavior and to clarify an effect of shock pressure 2. Maskelynite in shergottite (Dhofar 019) to estimate its shock pressure
Experimentally shocked plagioclase Sample: single crystal plagioclase (Ab60An40) from Norway Experiments: shocked by single-stage light-gas gun at 20, 30 and 40 GPa Measurements: polarized microscopic observation, EPMA analysis and CL and Raman spectroscopy
Meteorite Dhofar 019 classification : olivine-bearing basaltic shergottite constituent : subhedral grains of pyroxene, olivine, and maskelynite (An38-68). 5mm 5mm Color CL image of Dhofar 019 Micrograph of Dhofar 019
CL spectra of experimentally shocked plagioclase CL spectra of experimentally shocked plagioclase
CL spectra of experimentally shocked plagioclase Lattice defect Al-O--Al Mn2+ Fe3+ CL spectra of experimentally shocked plagioclase
CL spectra of experimentally shocked plagioclase Lattice defect STE Al-O--Al Mn2+ Fe3+ CL spectra of experimentally shocked plagioclase
Raman spectra of shocked plagioclase peak Intensity 0 > 20 > 30 > 40 (GPa) Alteration of structural configuration related to luminescence center Raman spectra of shocked plagioclase
Peak shift in yellow region (Mn2+) 0 GPa : 560 nm (yellow) ・ low strength of crystal fields ・ tetrahedral site 20, 30 and 40 GPa : 630 nm ・ high strength of crystal fields ・ octahedral site Destruction of TO4 framework caused by shock pressure
PDFs produced by experimentally shock pressure A B (A) Panchromatic CL image of plagioclase shocked at 40 GPa and (B) 3D Raman intensity map
CL images of maskelynite in Dhofar 019 A 5mm B C 0.5mm (A) Color CL image of Dhofar 019, (B) of maskelynite and (C) panchromatic CL image of maskelynite
CL spectra of maskelynite Blue emission CL spectra of maskelynite
CL spectra of maskelynite Blue emission Blue emission STE Fe3+ CL spectra of maskelynite
CL spectra of maskelynite Blue emission CL spectra of shocked plagioclase and maskelynite
Raman spectra of maskelynite Raman spectra of shocked plagioclase and maskelynite
Conclusion Experimentally shocked plagioclase ・ CL intensity decreases with an increase of shock pressure. ・ Shock-induced pressure causes the alteration of structural configuration related to luminescence center. New application of CL to estimation of shock pressure Maskelynite in Dhofar 019 ・ Maskelynite in Dhofar 019 have similar CL and Raman features to experimentally shocked plagioclase at 40 GPa. Shock pressure induced on Dhofar 019 at ~40 GPa