Lee, M.R.

Lindgren, Paula

Quirico, E.

Sparkes, R.

English

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    Lindgren, P., Sparkes, R., Quirico, E., and Lee, M.R. (2015) Exploring Thermal Processing of the Mildly Aqueously Altered Cm2 Eet 96029 Using Sulphide Mineralogy and Carbon Structure [abstract]. In: 78th Annual Meeting of the Meteoritical Society (2015), Berkeley, CA, USA, 27-31 Jul 2015.    Copyright © 2015 The Authors   A copy can be downloaded for personal non-commercial research or study, without prior permission or charge  Content must not be changed in any way or reproduced in any format or medium without the formal permission of the copyright holder(s)   When referring to this work, full bibliographic details must be given     http://eprints.gla.ac.uk/107603    Deposited on: 24 June 2015                 Enlighten – Research publications by members of the University of Glasgow http://eprints.gla.ac.uk EXPLORING THERMAL PROCESSING OF THE MILDLY AQUEOUSLY ALTERED CM2 EET 96029 USING SULPHIDE MINERALOGY AND CARBON STRUCTURE. P. Lindgren1, R. Sparkes2, E. Quirico3 and M.R. Lee1. 1University of Glasgow, U.K. paula.lindgren@glasgow.ac.uk 2University of Manchester, U.K. 3University of Grenoble, France.  Introduction: EET 96029 is one of the least aqueously al-tered CMs yet described with attributes such as chondrule mesostasis glass, gehlenite bearing CAIs and amorphous material in the matrix [1]. Mildly altered CMs are rare but important for reconstructing the earliest history of parent body aqueous altera-tion [2]. In addition to aqueous processing, many CMs are also affected by post-hydration thermal metamorphism [3]. It is im-portant to establish the degree of heating in CMs to disentangle features that could be a result of either a pristine nature with only minor aqueous alteration, or dehydration caused by post-aqueous thermal processing. Carbon can be a useful tool for reconstruct-ing CM thermal history since it gradually increases in structural order with heating [4]. Sulphide composition and microstructure is another measure that can be used to trace thermal events in CMs [5]. Here we have used both Raman spectroscopy of carbon and petrography of sulphides to determine if EET 96029 is near pristine or has been thermally metamorphosed. Methods: BSE imaging and quantitative elemental ED X-ray analyses of sulphides was carried out on a polished thin section of EET 96029 using a field emission Zeiss Sigma SEM operated at 20 kV. Carbon in powdered samples of EET 96029 and six other CM meteorites chosen for comparison (Cold Bokkeveld, Murchison, LON 94101, PCA 91008, QUE 93005 and SCO 06043) was analysed using a Renishaw inVia Raman microscope operated with a 514 nm laser. The collected Raman spectra were processed using automated fitting procedures [6]. Results and discussion: Grains of pentlandite are rare or ab-sent in EET 96029, possibly owing to the mild aqueous alteration [7]. However, nine out of eleven analysed sulphides are com-posed of pyrrhotite with µm-sized lamellae of pentlandite, which implies heating to 300-750 °C [5]. The processed Raman spectra were plotted in a carbon D (FWHM) vs D/G (intensity) diagram. The data show that PCA 91008 is more thermally altered than the rest of the samples; it has a higher D/G (intensity) and a lower D (FWHM), consistent with previous studies [4]. EET 96029 has a slightly higher D/G (intensity) than the other 5 CMs, which is possibly a sign of mild heating, although this interpretation is tentative as carbon is fairly insensitive to mild thermal metamor-phism. We conclude that EET 96029 is one of the least aqueously altered CMs yet described but its sulphide petrogra-phy, and possibly its carbon structure, implies that it has under-gone mild heating. This meteorite therefore suggests that aqueous alteration and thermal metamorphism were not necessarily cou-pled, which has important implications for our understanding of parent body internal structure and evolution. References: [1] Lindgren and Lee 2015. Abstract#1760 46th LPSC [2] Hewins et al. 2014. GCA 124:190-222 [3] Nakamura 2005. J. Min. Pet. Sci. 100:260-272 [4] Quirico et al. 2014. GCA 136:80-99 [5] Kimura et al. 2011. MAPS 46:431-442 [6] Sparkes et al. 2013. App. Spec. 67:779-788 [7] Zolensky et al. 1995. GCA 59:4707-4712. Acknowledgements: NASA ANSMET, NHM London, UK-STFC. 5223.pdf78th Annual Meeting of the Meteoritical Society (2015)

Exploring Thermal Processing of the Mildly Aqueously Altered Cm2 Eet 96029 Using Sulphide Mineralogy and Carbon Structure [abstract]

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Lindgren, P., Sparkes, R., Quirico, E., and Lee, M.R. (2015) Exploring 
Thermal Processing of the Mildly Aqueously Altered Cm2 Eet 96029 Using 
Sulphide Mineralogy and Carbon Structure [abstract]. In: 78th Annual 
Meeting of the Meteoritical Society (2015), Berkeley, CA, USA, 27-31 Jul 
2015. 
 
 
 
Copyright © 2015 The Authors 
 
 
A copy can be downloaded for personal non-commercial research or 
study, without prior permission or charge 
 
Content must not be changed in any way or reproduced in any format 
or medium without the formal permission of the copyright holder(s) 
 
 
When referring to this work, full bibliographic details must be given 
 
 
  
http://eprints.gla.ac.uk/107603 
 
 
 
Deposited on: 24 June 2015 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Enlighten – Research publications by members of the University of Glasgow 
http://eprints.gla.ac.uk 
EXPLORING THERMAL PROCESSING OF THE 
MILDLY AQUEOUSLY ALTERED CM2 EET 96029 
USING SULPHIDE MINERALOGY AND CARBON 
STRUCTURE. 
P. Lindgren1, R. Sparkes2, E. Quirico3 and M.R. Lee1. 
1University of Glasgow, U.K. paula.lindgren@glasgow.ac.uk 
2University of Manchester, U.K. 3University of Grenoble, 
France. 
 
Introduction: EET 96029 is one of the least aqueously al-
tered CMs yet described with attributes such as chondrule 
mesostasis glass, gehlenite bearing CAIs and amorphous material 
in the matrix [1]. Mildly altered CMs are rare but important for 
reconstructing the earliest history of parent body aqueous altera-
tion [2]. In addition to aqueous processing, many CMs are also 
affected by post-hydration thermal metamorphism [3]. It is im-
portant to establish the degree of heating in CMs to disentangle 
features that could be a result of either a pristine nature with only 
minor aqueous alteration, or dehydration caused by post-aqueous 
thermal processing. Carbon can be a useful tool for reconstruct-
ing CM thermal history since it gradually increases in structural 
order with heating [4]. Sulphide composition and microstructure 
is another measure that can be used to trace thermal events in 
CMs [5]. Here we have used both Raman spectroscopy of carbon 
and petrography of sulphides to determine if EET 96029 is near 
pristine or has been thermally metamorphosed. 
Methods: BSE imaging and quantitative elemental ED X-ray 
analyses of sulphides was carried out on a polished thin section 
of EET 96029 using a field emission Zeiss Sigma SEM operated 
at 20 kV. Carbon in powdered samples of EET 96029 and six 
other CM meteorites chosen for comparison (Cold Bokkeveld, 
Murchison, LON 94101, PCA 91008, QUE 93005 and SCO 
06043) was analysed using a Renishaw inVia Raman microscope 
operated with a 514 nm laser. The collected Raman spectra were 
processed using automated fitting procedures [6]. 
Results and discussion: Grains of pentlandite are rare or ab-
sent in EET 96029, possibly owing to the mild aqueous alteration 
[7]. However, nine out of eleven analysed sulphides are com-
posed of pyrrhotite with µm-sized lamellae of pentlandite, which 
implies heating to 300-750 °C [5]. The processed Raman spectra 
were plotted in a carbon D (FWHM) vs D/G (intensity) diagram. 
The data show that PCA 91008 is more thermally altered than the 
rest of the samples; it has a higher D/G (intensity) and a lower D 
(FWHM), consistent with previous studies [4]. EET 96029 has a 
slightly higher D/G (intensity) than the other 5 CMs, which is 
possibly a sign of mild heating, although this interpretation is 
tentative as carbon is fairly insensitive to mild thermal metamor-
phism. We conclude that EET 96029 is one of the least 
aqueously altered CMs yet described but its sulphide petrogra-
phy, and possibly its carbon structure, implies that it has under-
gone mild heating. This meteorite therefore suggests that aqueous 
alteration and thermal metamorphism were not necessarily cou-
pled, which has important implications for our understanding of 
parent body internal structure and evolution. 
References: [1] Lindgren and Lee 2015. Abstract#1760 46th 
LPSC [2] Hewins et al. 2014. GCA 124:190-222 [3] Nakamura 
2005. J. Min. Pet. Sci. 100:260-272 [4] Quirico et al. 2014. GCA 
136:80-99 [5] Kimura et al. 2011. MAPS 46:431-442 [6] Sparkes 
et al. 2013. App. Spec. 67:779-788 [7] Zolensky et al. 1995. GCA 
59:4707-4712. Acknowledgements: NASA ANSMET, NHM 
London, UK-STFC. 
5223.pdf78th Annual Meeting of the Meteoritical Society (2015)


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Exploring Thermal Processing of the Mildly Aqueously Altered Cm2 Eet 96029 Using Sulphide Mineralogy and Carbon Structure [abstract]

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