Cathodoluminescence imaging and spectral analyses of phosphates in the Martian meteorites: A review.

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Cathodoluminescence imaging and spectral analyses
of phosphates in the Martian meteorites A review.

• A. Gucsik1, W. J. Protheroe, Jr. 2, J.A.R.
  Stirling3, K. Ninagawa4, H. Nishido5, T.
  Okumura5, N. Matsuda6, Sz. Berczi7, Sz. Nagy7, A.
  Kereszturi7 and H. Hargitai7

1Max Planck Institute for Chemistry, Mainz,
Germany (gucsik_at_mpch-mainz.mpg.de) 2AOL Inc.,
Houston, USA 3Geological Survey of Canada,
Ottawa, Canada 4Okayama Unversity of Science,
Dept. of Applied Physics, Okayama, Japan 5Okayama
Unversity of Science, RINS, Okayama,
Japan 6Okayama Unversity of Science, ISEI,
Tottori, Japan 7Eotvos Lorand University,
Budapest, Hungary
NIPR, Tokyo, 07 June 2007
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Contents

• Basics of the cathodoluminescence signal.
• CL properties of some Martian meteorites.
• Conclusions.

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• Purpose
• Scanning Electron Microscopy-Cathodoluminescence
  (SEM-CL) techniques provide better spatial
  resolution images of the minerals than the
  standard optical microscope ones.
• Moreover, SEM-CL spectral information might give
  some details on the activator elements presented
  in the in minerals.
• These observations can aid to understand more
  about the formation mechanism of different types
  of phosphates.
• It is important to note, that CL characteristics
  of the Martian meteorite samples have not been
  documented in great details, so far.
• Non-destructive method.

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based on Goetze, 1999
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based on Goetze, 1999
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based on Goetze, 1999
7
based on Goetze, 1999
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based on Goetze, 1999
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based on Goetze, 1999
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based on Goetze, 1999
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Mechanism of CL (unshocked)-Band Gap Model
Processes of CL produced in insulator crystals
based on Goetze, 1999
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Mechanism of CL (shocked)-Band Gap Model
Kayama et al. (2007) Okumura et al. (2007)
based on Nasdala, 2003
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Reference material
CL micrograph and spectrum of apatite
based on Goetze, 1999
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Samples and Experimental Procedure We studied
two polished thin sections of the Y000593
nakhlite Martian meteorite supplied from the
National Institute of Polar Research (NIPR,
Tokyo, Japan). SEM-CL imaging and CL spectral
analyses were performed on the selected thin
sections coated with a 20-nm thin film of carbon
in order to avoid charge build-up. SEM-CL images
were collected using a scanning electron
microscope (SEM), JEOL 5410LV, equipped with a CL
detector, Oxford Mono CL2, which comprises an
integral 1200 grooves/mm grating monochromator
attached to reflecting light guide with a
retractable paraboloidal mirror. The operating
conditions for all SEM-CL investigation as well
as SEM and backscattered electron (BSE)
microscopy were accelerating voltage 15 kV, and
3.0-5.0 nA at room temperature. CL spectra were
recorded in the wavelength range of 300-800 nm,
with 1 nm resolution by the photon counting
method using a photomultiplier detector,
Hamamatsu Photonics R2228.
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Y-000593 nakhlite
SE
SEM-CL CL

• Apatite (Ap) was found as a mesostasis mineral,
  which occurs in veinlets between mostly
  clinopyroxene (Cpx) and plagioclase (Pl).
• EDS analysis reveals that this apatite is a
  chloroapatite, which contains minor fluorine, but
  uncertain of CO2 and OH.

Matsuda et al. (2007)
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CAN-AM Mars Meteorite Research Team
Research Team
Members of the research team are John A. R.
Stirling (GSC), Walter J. Protheroe Jr., and Pat
A. Hunt (GSC). GSC Geological Survey of Canada
(Natural Resources Canada)
From left John A. R. Stirling, Walter J.
Protheroe Jr. and Pat A. Hunt
Research Team
Photograph by Katherine E. Venance (GSC)
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CAN-AM Mars Meteorite Research Team
Equipment
Equipment used in the research of the Mars
meteorites is based at the Geological Survey of
Canada, 601 Booth St., 7th floor, Ottawa,
Ontario, Canada. The equipment shown below is
manufactured by Cameca.
Cameca MBX Camebax Electron Microprobe This
instrument is a fully automated electron
microprobe with four wavelength spectrometers
and a Kevex Electron Dispersive Spectrometer
(EDS). Upgrades to this system have included
digital imaging, advanced EDS imaging, and
Cathodo- luminescence (CL) spectrometry
and imaging system by EOS.
EOS Electron Optic Service, Inc., Nepean, ONT.,
Canada Cameca, MBX and Camebax are trademarks of
Cameca (France) Kevex is a trademark of Kevex
Corporation.
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CAN-AM Mars Meteorite Research Team
Equipment
Also used in the analysis of the Mars meteorites
at the Geological Survey of Canada is the Cameca
SX-50.
Cameca SX-50 Camebax Electron Microprobe The
SX-50 is a new generation of automated electron
microprobes. This one has four spectrometers,
a digital imaging system and a EDS System by
PGT. The software has been upgraded by Advance
Microbeam.
Advance Microbeam - Advance Microbeam
Corporation Cameca, MBX and Camebax are
trademarks of Cameca (France) PGT is a trademark
of Princeton Gamma Tech Corporation.
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ALH-84001 sample N fragments (3734, 3738, and
3739)
SE SEM-CL
Colour-enhanced CL

• Whitlockite (Beta-Ca-phosphate)

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Conclusions

• CL spectroscopy combined with SEM-CL imaging is
  a powerful technique to characterize phosphates
  in the Martian meteorites.
• This also can aid to distinguish anhydrous or
  hydrous phosphates.
• This technique also can play a key role in the
  in-situ measurements of the mineralogical
  evidences of the atmospheric-rock-fliud
  interactions on Mars.

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Thank you very much for your attention