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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