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RGClark
2005-Jul-27, 10:03 AM
From the program of the September, 2005 AAS Division of Planetary Sciences meeting:

http://www.aas.org/publications/baas/v37n3/dps2005/dps2005block.html


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[32.12] Outcrops of clay rich crust in Mawrth Vallis, Mars, revealed by OMEGA and HRSC/MEX
D. Loizeau, N. Mangold (IDES-Orsay), F. Poulet, J.-P. Bibring, A. Gendrin, C. Gomez, Y. Langevin, B. Gondet (IAS-Orsay), V. Ansan, P. Masson (IDES-Orsay), G. Neukum (FU-Berlin), OMEGA Team, HRSC Team

The hyperspectral imager OMEGA aboard Mars Express found hydrated minerals in the region of Mawrth Vallis, Mars, by the detection of the 1.9 μm hydration absorption band, caused by the H2O molecule inside the mineral structure. For these hydrated minerals, the combination bands due to the Fe-OH bond at 2.3 μm and the Al-OH bond at 2.2 μm reveal the presence of clay minerals: ferric smectites and montmorillonites (Poulet et al., this conference). HRSC images indicate that the clays correspond to bright outcrops on the plateaus each side of Mawrth Vallis. These plateaus are part of highly cratered Noachian terrain (> 3.7 Gy). On these bright clay rich outcrops, MOC images show light-toned layered deposits, as seen by Malin and Edgett (Science, 2000). The intense wind erosion of these outcrops implies that clays are not only surfacial, but that the bright sedimentary rock itself is made of clays. The observation of such a large amount of clays in this region implies extensive alteration of igneous rocks by water, and the subsequent deposition of clays.

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http://www.aas.org/publications/baas/v37n3/dps2005/575.htm


Bob Clark

Launch window
2005-Jul-27, 12:43 PM
good information on Mars

publiusr
2005-Jul-27, 07:59 PM
How much will pottery from Martian soil--with Martian water in it--cost at Sotheby's? (don't let them drink it this time).

Maksutov
2005-Jul-27, 08:38 PM
That's great news. I wonder how old those clays are? Hard to reconcile clay formation with a Mars that's almost always been cold, as in well below the freezing point of water.

Concerning


[edit] These plateaus are part of highly cratered Noachian terrain (> 3.7 Gy)...

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http://www.aas.org/publications/baas/v37n3/dps2005/575.htm


Bob Clark
Oh no! Does this mean that Bob Jones University will soon be sponsoring an expedition to find the remains of the Mars ark? #-o

Hmmm. "ferric smectites". Didn't we have one of those posting here recently about the Sun's solid surface? :D

publiusr
2005-Jul-27, 09:11 PM
Can we get a rimshot for that last one?

RGClark
2005-Jul-28, 12:57 PM
That's great news. I wonder how old those clays are? Hard to reconcile clay formation with a Mars that's almost always been cold, as in well below the freezing point of water.

Concerning


[edit] These plateaus are part of highly cratered Noachian terrain (> 3.7 Gy)...

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http://www.aas.org/publications/baas/v37n3/dps2005/575.htm


Bob Clark




It is interesting these clays are part of the Noachian terrain on Mars, the earliest epoch in Mars geological history, earlier than about 3.5 to 3.8 billion years ago.
This is the period when it was hypothesized that an ocean could have existed on Mars. The recent announcement from Mars meteorite analysis that Mars has been cold for billions of years might not be in conflict with this if this ocean disappeared subsequent to the Noachian age.


Bob Clark

01101001
2006-Apr-21, 05:21 PM
BBC News: Rock maps revise Martian history (http://news.bbc.co.uk/2/hi/science/nature/4926370.stm)


Mineral maps based on data from Europe's Mars Express probe are helping scientists piece together a detailed picture of the Red Planet's history.
[...]
The maps show the planet had three distinct geological eras; the team believes the earliest of these would have been the most hospitable for life.
[...]
The first age, the Phyllocian era, lasted from just after the planet's birth to about four billion years ago. Ancient rocks show the present of clay-rich minerals - phyllosilicates - which to form would have required a water-abundant alkaline environment.
[...]
The second era emerged after a dramatic shift in the Martian climate. Now sulphate minerals dominated and the researchers have labelled this the Theiikian era, named after the Greek for sulphate.
[...]
The third era which continues to the present day, began roughly 3.5 billion years ago. Minerals during this time were not formed in the presence of water.

"All the water disappeared apart from the two big polar caps, and the third era began," said Professor Bibring.