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Creator |
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Creator |
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Creator |
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Creator |
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Creator |
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Creator |
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Creator |
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Creator |
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Creator |
ext-e3c8d827ad598d4df9982e8db025f2bb |
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Date |
2011-08 |
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Date |
2011-08 |
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Is Part Of |
p00320633 |
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Is Part Of |
repository |
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abstract |
Within the context of present and future in situ missions to Mars to investigate its
habitability and to search for traces of life, we studied the habitability and traces
of past life in ~3.5 Ga-old volcanic sands deposited in littoral environments an analogue
to Noachian environments on Mars. The environmental conditions on Noachian Mars (4.1–3.7
Ga) and the Early Archaean (4.0–3.3 Ga) Earth were, in many respects, similar: presence
of liquid water, dense CO<sub>2</sub> atmosphere, availability of carbon and bioessential
elements, and availability of energy. For this reason, information contained in Early
Archaean terrestrial rocks concerning habitable conditions (on a microbial scale)
and traces of past life are of relevance in defining strategies to be used to identify
past habitats and past life on Mars.
One such example is the 3.446 Ga-old Kitty’s Gap Chert in the Pilbara Craton, NW.
Australia. This formation consists of volcanic sediments deposited in a coastal mudflat
environment and is thus a relevant analogue for sediments deposited in shallow water
environments on Noachian Mars. Two main types of habitat are represented, a volcanic
(lithic) habitat and planar stabilized sediment surfaces in sunlit shallow waters.
The sediments hosted small (<1 μm in size) microorganisms that formed colonies on
volcanic particle surfaces and in pore waters within the volcanic sediments, as well
as biofilms on stabilised sediment surfaces. The microorganisms included coccoids,
filaments and rare rod-shaped organisms associated with microbial polymer (EPS). The
preserved microbial community was apparently dominated by chemotrophic organisms but
some locally transported filaments and filamentous mat fragments indicate that possibly
photosynthetic mats formed nearby. Both microorganisms and sediments were silicified
during very early diagenesis.
There are no macroscopic traces of fossilised life in these volcanic sediments and
sophisticated instrumentation and specialized sample preparation techniques are required
to establish the biogenicity and syngenicity of the traces of past life. The fact
that the traces of life are cryptic, and the necessity of using sophisticated instrumentation,
reinforces the challenges and difficulties of in situ robotic missions to identify
past life on Mars. We therefore recommend the return of samples from Mars to Earth
for a definitive search for traces of life. |
| 32340 |
abstract |
Within the context of present and future in situ missions to Mars to investigate its
habitability and to search for traces of life, we studied the habitability and traces
of past life in ~3.5 Ga-old volcanic sands deposited in littoral environments an analogue
to Noachian environments on Mars. The environmental conditions on Noachian Mars (4.1–3.7
Ga) and the Early Archaean (4.0–3.3 Ga) Earth were, in many respects, similar: presence
of liquid water, dense CO<sub>2</sub> atmosphere, availability of carbon and bioessential
elements, and availability of energy. For this reason, information contained in Early
Archaean terrestrial rocks concerning habitable conditions (on a microbial scale)
and traces of past life are of relevance in defining strategies to be used to identify
past habitats and past life on Mars.
One such example is the 3.446 Ga-old Kitty’s Gap Chert in the Pilbara Craton, NW.
Australia. This formation consists of volcanic sediments deposited in a coastal mudflat
environment and is thus a relevant analogue for sediments deposited in shallow water
environments on Noachian Mars. Two main types of habitat are represented, a volcanic
(lithic) habitat and planar stabilized sediment surfaces in sunlit shallow waters.
The sediments hosted small (<1 μm in size) microorganisms that formed colonies on
volcanic particle surfaces and in pore waters within the volcanic sediments, as well
as biofilms on stabilised sediment surfaces. The microorganisms included coccoids,
filaments and rare rod-shaped organisms associated with microbial polymer (EPS). The
preserved microbial community was apparently dominated by chemotrophic organisms but
some locally transported filaments and filamentous mat fragments indicate that possibly
photosynthetic mats formed nearby. Both microorganisms and sediments were silicified
during very early diagenesis.
There are no macroscopic traces of fossilised life in these volcanic sediments and
sophisticated instrumentation and specialized sample preparation techniques are required
to establish the biogenicity and syngenicity of the traces of past life. The fact
that the traces of life are cryptic, and the necessity of using sophisticated instrumentation,
reinforces the challenges and difficulties of in situ robotic missions to identify
past life on Mars. We therefore recommend the return of samples from Mars to Earth
for a definitive search for traces of life. |
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authorList |
authors |
| 32340 |
issue |
10 |
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issue |
10 |
| 32340 |
status |
peerReviewed |
| 32340 |
volume |
59 |
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volume |
59 |
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type |
AcademicArticle |
| 32340 |
type |
Article |
| 32340 |
label |
Westall, Frances; Foucher, Frédéric; Cavalazzi, Barbara; de Vries, Sjoukje
T.; Nijman, Wouter; Pearson, Victoria ; Watson, Jon ; Verchovsky, Alexander ;
Wright, Ian; Rouzaud, Jean-Noel ; Marchesini, Daniele and Anne, Severine (2011).
Volcaniclastic habitats for early life on Earth and Mars: A case study from 3.5 Ga-old
rocks from the Pilbara, Australia. Planetary and Space Science, 59(10) pp. 1093–1106.
|
| 32340 |
label |
Westall, Frances; Foucher, Frédéric; Cavalazzi, Barbara; de Vries, Sjoukje T.;
Nijman, Wouter; Pearson, Victoria ; Watson, Jon ; Verchovsky, Alexander ; Wright,
Ian; Rouzaud, Jean-Noel ; Marchesini, Daniele and Anne, Severine (2011). Volcaniclastic
habitats for early life on Earth and Mars: A case study from 3.5 Ga-old rocks from
the Pilbara, Australia. Planetary and Space Science, 59(10) pp. 1093–1106. |
| 32340 |
Title |
Volcaniclastic habitats for early life on Earth and Mars: A case study from 3.5 Ga-old
rocks from the Pilbara, Australia |
| 32340 |
Title |
Volcaniclastic habitats for early life on Earth and Mars: A case study from 3.5 Ga-old
rocks from the Pilbara, Australia |
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in dataset |
oro |