MER updates:

Highlights of today’s scientific presentations:

* The most-mature images were in subdued greys and ochres – no blues or shocking reds.
* Plans for Spirit are still in flux. Everyone had a different opinion:- Probably won’t go into the crater. Steve Squyres reckons they will stay for up to 3 weeks, say Sol 90 before heading for the Eastern Hills. Jim Bell reckoned they would depart “soon”. No plans to visit the heatshield (Opportunity will do that).
* Steve Squyres “We will still be going strong at SOL 240”
* Jim Bell, re Pancam “Hopefully, you’re having just as much fun as we are”
* More Sulphates found by OMEGA

In more detail (apologies for rushed format – these are my notes, hastily typed. I have no time to add the fancy embroidery around them!):

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Opportunity

Steve Squyres: S, Cl, K in rock crusts and dusts. Opportunity rock has S as high as 23% sulphate, plus highly variable Bromine – like some Terrestrial evaporates.
Jarosite from Mossbauer, Ca- and Mg- Sulphates from mini-TES.
Spherules are concretions, Haematite is in the spherules.
Plan is to go from Eagle Crater (the one Opportunity is in) to Endurance Crater, then visit the heatshield impact site and then head south for “etched terrain”, some 2km distant.
These rocks are interesting because there is “potential for preservation of life signs”

Ray Arvidson: Pale rocks are layered and about 200m thick, with a dark haematite capping. Not all spherules are the same – different colours, shapes, textures, sizes etc. This is more than just spheroids “twinning”. Rocks from acid sulphate diagenesis or direct chemical precipitation. He is interested in getting onto the haematite plains.

Dick Morris: The Fe is principally in Jarosite (30-40% of Fe) and Haematite (30%). No Goethite seen. Jarosite is equivalent to 10% H2O equivalent. Formed by acid sulphate alteration of basaltic precursors – the type of Jarosite is quite diagnostic. There is more sulphate than Jarosite, so other phases exist. I asked if the tabular voids could have been ice. He said sure, or perhaps even H2SO4 crystals!

Phil Christensen: Mini TES spectra fits to Gypsum (Ca sulphate) and Epsomite (Mg). Only “minor” Jarosite in spectra, and some Goethite – obviously, we need to lock the Mossbauer people in a room with Phil and see who comes out alive. Rocks consist of approx equal proportions of sheet silicates (or glass) / sulphates / Fe oxides (mostly haematite). 250,000 mini-TES spectra to date – a huge effort to work with in the future. Depositional environment is “not hydrothermal” but requires standing water (I tried my Sabkha model on him in the break, and he said that was OK, so long as the surface was wet)

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Spirit

Jim Bell: All sizeable rocks are vesicular olivine basalts. No sediments or other igneous types. There is a mineral unknown from their spectral library (and therefore rare or even unknown on Earth), with a distinctive peak at 11 microns. There is a crusty surface to the soils, and no impact breccias – either these didn’t form under Mars surface conditions, or they weathered rapidly.

Hap McSween: Soils have textural complexity. Rocks are Si-undersaturated olivine basalts (“Picrites”). 31-32% olivine. Interestingly, they DON’T match the SNC meteorites. These basalts are richer in Al, like Earth basalts, but more iron rich. With this composition, they match the TES type I/II materials. No fluvial or lacustrine mineralogy (yet)

Phil Christensen: All sizeable rocks have “identical” spectra. A few % carbonate disseminated in soils and dusts.

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A rather duller presentation followed on Mars Express.

Gerhard Neukum showed much the same colour pictures already released to the web, and showed crater count ages for the calderas of Olympus Mons, Ascraeus Mons, and Albor and Hecates Tholus. None younger than 100 Ma, some up to 2+ Ga. Finished with a nice 3D fly-through.

OMEGA presentation – South pole – even the supposed CO2 areas have about 15% ice mixed in on a fine scale, or perhaps seen through a cover of transparent CO2. Olivine and Pyroxene detected across Mars, as for TES.

The “surprise” news – Light coloured rock outcrops in and around Valles Marineris are clearly sulphates (like Opportunity, like I expected). Mg Sulphates detected in 2 forms – Epsomite and Kieserite – vary in degree of hydration.