M. Kayama, T. Nakazato, H. Nishido, K. Ninagawa, A. Gucsik, and Sz. Bérczi
Cathodoluminescence and Raman spectroscopic
study of maskelynite in shergottite (Dhofar 019)
and experimentally shocked plagioclase
Introduction
Dhofar 019 shocked in the range of 30-35 GPa
judging from the formation of maskelynite
Dhofar 019 : olivine-bearing basaltic shergottite
Badjukov D. D et al. (2001)
Taylor L. A et al (2002)
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
Micrograph of Dhofar 019 Color CL image of Dhofar 019
Dhofar 019
classification : olivine-bearing basaltic shergottite
constituent : subhedral grains of pyroxene, olivine, and
maskelynite (An38-68).
5mm 5mm
CL spectra of experimentally shocked plagioclase
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
Al-O--Al Mn2+Fe3+
STE
Raman spectra of shocked plagioclase
Raman spectra of shocked plagioclase
Alteration of structural
configuration related to
luminescence center
peak Intensity
0 > 20 > 30 > 40 (GPa)
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
(A) Panchromatic CL image of plagioclase shocked at 40 GPa and
(B) 3D Raman intensity map
PDFs produced by experimentally shock pressureA
B
A 5mm
CL images of maskelynite in Dhofar 019
B
0.5mm
(A) Color CL image of Dhofar 019, (B) of maskelynite and
(C) panchromatic CL image of maskelynite
C
CL spectra of maskelynite
CL spectra of maskelynite
Blue emission
Blue emissionBlue emission
CL spectra of maskelynite
CL spectra of maskelynite
Fe3+
STE
CL spectra of shocked plagioclase and maskelynite
CL spectra of maskelynite
Blue emission
Raman spectra of shocked plagioclase and maskelynite
Raman spectra of maskelynite
Conclusion
・ CL intensity decreases with an increase of shock pressure.
・ Shock-induced pressure causes the alteration of structural
configuration related to luminescence center.
・ Maskelynite in Dhofar 019 have similar CL and Raman features to
experimentally shocked plagioclase at 40 GPa.
Maskelynite in Dhofar 019
New application of CL to estimation of shock pressure
Shock pressure induced on Dhofar 019 at ~40 GPa
Experimentally shocked plagioclase
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