Download Alteration on Mars

Alteration on Mars: study of near-infrared
spectra of terrestrial basalts altered
in contrasted climate conditions
Joanna GURGUREWICZ1,2, Daniel MEGE1,3, Véronique CARRERE3,
Anne GAUDIN3, Joanna KOSTYLEW4, Yann MORIZET3, Marta SKIŚCIM1
1WROONA
Group, Institute of Geological Sciences PAS, Wrocław, Poland
2Space
3Laboratoire
Research Centre PAS, Warsaw, Poland
de Planétologie et Géodynamique, Université de Nantes, France
4Institute
of Geological Sciences, University of Wrocław, Poland
Second MPSE Workshop
Warsaw, 3-5 June 2014
CLIMATE ON MARS
Evolution of the Martian obliquity in the past 10 Myr. The main
obliquity periodicity is about 120,000 earth years.
Laskar et al. 2002
Levrard et al. 2004
Second MPSE Workshop
Alteration on Mars
Gurgurewicz et al.
05-06-2014
MAFIC ROCKS ON MARS
Mafic rocks are widespread at the surface of Mars:
• composition of Martian meteorites
• geomorphology
• orbital spectroscopic data sets
• in situ analyses
Total alkalis-silica diagram used
for classification of volcanic rocks.
Gusev RAT-ground and RATbrushed compositions for the
same rocks are connected by tielines. Analyses of Gusev rocks
and soils, martian meteorites, and
global GRS data (calculated on a
volatile-free basis) indicate a crust
dominated by basalts. TESderived data and possibly the
Mars Pathfinder rock composition
may reflect alteration.
McSween et al. 2009
Second MPSE Workshop
Alteration on Mars
Gurgurewicz et al.
05-06-2014
ALTERATION ON MARS
Can information on the Martian environmental conditions prevailing during the alteration
of its basaltic crust be inferred from data collected during space missions?
Mustard et al., 2008
Mustard et al. 2008
Second MPSE Workshop
Alteration on Mars
Gurgurewicz et al.
05-06-2014
TERRESTRIAL ANALOGUES
Basaltic analogues used in this study are altered in arid cold and arid hot
environments, as well as hot environments in which wet and arid climates
occurred successively; any of these conditions may have been representative
of the alteration conditions on Mars, present or past.
The studied basalts are located
in the Udokan area of Siberia,
and in the Ogaden region of
southeast Ethiopia.
Location of the Udokan volcanic field and Ogaden basalts. The dark
patches are the volcanic exposures. The sampling sites are shown
by circles: U – Udokan volcanic field; G – Gode; KD – Kebri Dehar;
W – Werder.
They are alkali basalts, Ti-rich,
and have the same mineralogical
structure.
Photomicrographs of representative basalts samples from Udokan
(a) and Ogaden (b). The phenocrysts include mainly plagioclase
and iddingsitized olivine. Polarizing microscope, plane polarized
light.
Second MPSE Workshop
Alteration on Mars
Gurgurewicz et al.
05-06-2014
METHODS
• Polarizing microscope
• ASD FieldSpec® 3 Spectrometer
• X-ray diffractometer Siemens D5000/D5005
• Scanning Electron Microscope JEOL 6400F
• Labram® Raman spectrometer
Second MPSE Workshop
Alteration on Mars
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05-06-2014
NEAR-INFRARED SPECTRA
IRON-RICH PRIMARY MINERALS
Second MPSE Workshop
Alteration on Mars
CLAYS
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NEAR-INFRARED SPECTRA
IRON HYDROXIDES
Second MPSE Workshop
ZEOLITES
Alteration on Mars
CARBONATES
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NEAR-INFRARED SPECTRA
Absorption band
(µm)
1.14
1.41-1.44
1.73
1.76
1.87
1.91-1.95
2.17
2.19
2.21-2.22
2.30
2.34
Secondary mineral phases
smectites, zeolites
smectites, ferrihydrite, zeolites
zeolites
ferrihydrite, zeolites, calcite
smectites, zeolites, calcite
smectites, iddingsite, ferrihydrite, zeolites
calcite
beidellite, zeolites
montmorillonite, zeolites
nontronite, zeolites
calcite
Udokan
RN01A/B RN02 RN03 RN04
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Ogaden
K1.30 K3.1 W1.4 W2.5 W3.2
WS1.2
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Absorption bands and corresponding mineral phases due to alteration identified in the Udokan and Ogaden basalt spectra
Second MPSE Workshop
Alteration on Mars
Gurgurewicz et al.
05-06-2014
NEAR-INFRARED SPECTRA
Reflectance spectra of the Ogaden
and Udokan fresh or nearly fresh rock
surfaces. The spectra are quite
similar, apart from the missing ~1 μm
absorption in two of the Udokan
basalt spectra.
Second MPSE Workshop
Alteration on Mars
Gurgurewicz et al.
05-06-2014
NEAR-INFRARED SPECTRA
Reflectance spectra of the Ogaden
and Udokan basalt alteration rind
surfaces. Note the parallel spectra
of the Udokan sample RN02 and
Ogaden sample K1.30 in the range
0.7-2.5 μm, and the nearly
identical spectra of the Udokan
sample RN01B and Ogaden
sample K3.1 in the range 1.9-2.4
μm. Water absorption band at 1.9
μm is almost always deeper in the
Ogaden than in the Udokan basalt
spectra, as detailed in the inset,
where the band depth is calculated
by subtracting from each spectrum
a convex continuum hull between
1.88 and 2.13 μm, following the
method presented by Morris et al.
(1982).
Second MPSE Workshop
Alteration on Mars
Gurgurewicz et al.
05-06-2014
NEAR-INFRARED SPECTRA
Reflectance spectra of the
Ogaden and Udokan basalt
powders.
Several
spectral
features, that are not apparent in
bulk rock spectra, appear. The
powder spectra of basalts
altered in arid hot environment
(Ogaden) show a first-order
positive spectral slope in the
range 0.9-2.0 μm, whereas
spectra of basalts altered in arid
cold environment (Udokan) have
a first-order negative spectral
slope.
Second MPSE Workshop
Alteration on Mars
Gurgurewicz et al.
05-06-2014
CONCLUSIONS & PERSPECTIVES
• The NIR spectra of the alteration rind surface and the internal part of the bulk samples
from cold and hot environment are very similar, suggesting that the NIR spectra of Martian
bulk rocks may be of limited help in identifying paleoenvironment conditions.
• Bulk rock spectra analysis reveals, however, that:
(1) spectra of the least altered rocks display clear absorption bands of smectites;
(2) the depth of the 1.9 μm water absorption band is not correlated with environmental
humidity, possibly due to the weathering effect of groundwater, or to the hydration state of
the secondary minerals.
• Additional compositional information can be retrieved from rock powder spectra: zeolites,
which are identified in the Udokan basalt spectra, are indicators of ancient presence of
groundwater or hydrothermal water.
• The presence of calcite and iddingsite is ascertained by other methods, but they are not
apparent in bulk rock spectra and only weakly apparent in powder spectra.
• Although the alteration conditions of the two series of terrestrial basalt samples are very
contrasted, analysis of near-infrared spectra could not unequivocally discriminate between
them.
• Other techniques are required for characterization of alteration features in basalts that
can accurately infer paleoclimate, and pottentially be used for in situ analysis on Mars.
Second MPSE Workshop
Alteration on Mars
Gurgurewicz et al.
05-06-2014
Thank you for your attention