New Mars Express And Huygens Results, ESA conference - November 30, 2005 Options

[tty]

Another MARSIS finding that seems to have been lost in yesterday's blizzard of releases is the apparent lack of a clear indication for basal melting at the north polar cap.  The cryospheric models that postulate a recycling of liquid water from polar basal melting towards putative deep seated aquifers in the equatorial regions (thereby serving as reservoirs for the circum-Chryse catastrophic outlfow channels) seem to have suffered.

Not necessarily. Even here on Earth some ice-caps are "cold-based", i e frozen to the substratum (the central part of the Scandinavian ice-cap during the last glaciation for example). If there is basal melting on Mars I would expect this to be a cyclic phenomenon. The existence of the layered terrain near the pole is a pretty strong proof of climatic cyclicity by itself.
The best evidence would be the morphology of the surface under the ice-cap. Wet-based ice moves over the substrate and has great erosive power while cold-based ice hardly erodes the substrate at all.
However I'm not sure whether MARSIS has sufficient definition to see e. g. drumlins or tunnel valleys beneath the ice.

tty

[helvick]

  Lastly web sites are ephemeral, many journals will not accept web links for precisely this reason, in addition to those above. 

+ much very valid comment deleted for brevity.

Yes the web is ephemeral but there is still an enormous benefit to be had from openly publishing scientific material online and early. The archival problem needs to be addressed for stuff that merit but even without that making this stuff available for searching and online cross referencing has an enormous benefit. There is simply too much knowledge out there locked into paper and that needs to change.

I was astonished to read this editorial from Nature. Clearly they are not as locked into the concept of old media as I had thought, my apologies.

[JonClarke]

+ much very valid comment deleted for brevity.

Yes the web is ephemeral but there is still an enormous benefit to be had from openly publishing scientific material online and early. The archival problem needs to be addressed for stuff that merit but even without that making this stuff available for searching and online cross referencing has an enormous benefit. There is simply too much knowledge out there locked into paper and that needs to change.

That is why conference abstracts are a such a good idea, they quickly get the information out that would otherwise take months or longer. there have been about a score full ME papers for example, but well over 100 absstracts. These are generally available on line these days, even before the conference.

For the final public study the results still need to be fully and independently reviewed. This can take a year or more. The period between acceptance and actual hard copy can be frustrating, and is longer than anyone would like, but it is hardly critical. the sky isn't going to fall in because a paper becomes available 6 months after the review process is complete, rather than 2 months.

As for paper knowledge being locked away, I disagree. Providing they are catalogued I can access paper knowledge from anywhere in the world within a few weeks. This is much more reliable that a web site which is here today and may be gone tomorow. But then, I am perhaps spoiled by access to an excellent library!

Death of print? Yeah right. We have heard this before.

But we digress from the point, of this thread, which is these amazing results in these two papers and the report on the web site. I really like the image on the ESA site (not in the nature paper) which shows the false colour OMEGA data draped over a 20 m resolution DEM derived from HRSC. you can see the compositional trends in individual beds. There must be a lot more of this stuff in press.

The 20 m HRSC DEM is a very powerful tool. You can drape any data set over it and see what the combination shows. For example, the 3 m resolution MOC images or THEMIS. I saw some nice stuff along these lines at the EGU some 6 months ago, so hopefully this will be coming out soon.

Jon

[Guest_BruceMoomaw_*]

I thought I remembered some earlier brief mentions of Mars Express finding phyllosilicates. Yep -- there are two abstracts mentioning it from the Septemeber DPS meeting, one of which has a bit more information.
http://www.aas.org/publications/baas/v37n3/dps2005/575.htm :

"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."

Moreover, it also turns out from the GSA meeting that MER-A has found one rock possibly containing phyllosilicates in the Columbia Hills.
http://gsa.confex.com/gsa/2005AM/finalprog...tract_95505.htm :

" 'Wooly Patch' is an outcrop having unique characteristics, investigated by the Mars Exploration Rover, Spirit, along the rover's traverse to the Columbia Hills. It is the softest rock abraded by the Rock Abrasion Tool at Gusev through sol 291. It shows hardened material at the edges of surface fractures, potentially involving cementation/deposition by fluid. It shows cataclastic texture in the interior matrix and extremely fine porous cuttings. The rock interior has distinct Vis-NIR spectra, and a distinct Mössbauer spectrum with a paucity of Fe2+ in olivine and an intense Fe2+(VI) spectral doublet with parameters slightly different from the pyroxene/glass component within plains basalts. Compositionally, targets on Wooly Patch form the endmembers in three chemical trends of Gusev rocks, and its major silicate-related cation ratios [TC/ICT and ICS/(ICS+ICL)] suggest a medium degree of polymerization (e.g., phyllosilicates). A modified normative calculation based on igneous mineralogy indicates an excess of Al2O3 and SiO2 in its composition. Mass-balance mixing-model calculations suggest phyllosilicates plus remnants of primary basaltic minerals to be the essential constituents that make up this outcrop. Phyllosilicate groups possessing similar cation ratios to those implied by the Wooly Patch analysis spots include the kaolinite, serpentine, chlorite, and septechlorite groups. The potential existence of kaolinite type Al-rich phyllosilicates within the Wooly Patch outcrop suggests a mildly acidic environment (pH from 4 to 6) in the past, and an open hydrologic system."

[Guest_paulanderson_*]

Unfortunately the odds for finding carbonates in Meridiani are not good. No trace of carbonates have ever been found on Mars despite fairly extensive searches from orbit. There probably never was any large amounts of Calcium in martian lakes.

Not quite; no large deposits of carbonates have been found yet, but Spirit did find traces, early on. Just traces, but better than none. And low concentrations globally. I remembered this from back in January, 2004:

http://marsrovers.jpl.nasa.gov/newsroom/pr.../20040109a.html

"Traces of carbonate minerals showed up in the rover's first survey of the site with its infrared sensing instrument, called the miniature thermal emission spectrometer or Mini-TES. Carbonates form in the presence of water, but it's too early to tell whether the amounts detected come from interaction with water vapor in Mars' atmosphere or are evidence of a watery local environment in the past, scientists emphasized.

"We came looking for carbonates. We have them. We're going to chase them," said Dr. Phil Christensen of Arizona State University, Tempe, leader of the Mini-TES team. Previous infrared readings from Mars orbit have revealed a low concentration of carbonates distributed globally. Christensen has interpreted that as the result of dust interaction with atmospheric water. First indications are that the carbonate concentration near Spirit may be higher than the Mars global average."

Unless those observations changed later, which I don't recall, then there are at least small amounts, but not none.

[Bob Shaw]

Not necessarily. Even here on Earth some ice-caps are "cold-based", i e frozen to the substratum (the central part of the Scandinavian ice-cap during the last glaciation for example). If there is basal melting on Mars I would expect this to be a cyclic phenomenon. The existence of the layered terrain near the pole is a pretty strong proof of climatic cyclicity by itself.
The best evidence would be the morphology of the surface under the ice-cap. Wet-based ice moves over the substrate and has great erosive power while cold-based ice hardly erodes the substrate at all.
However I'm not sure whether MARSIS has sufficient definition to see e. g. drumlins or tunnel valleys beneath the ice.

tty

The MARSIS 'image' of the polar cap certainly is low resolution, and yes, the press release seemed quite specific about no meltwater being found (presumably that'd show up really well).

Of more positive interest were the prospects of ancient sub-surface crater remnants in Chryse and their relationship to water deposits.

Bob Shaw

[Guest_paulanderson_*]

The Sun newspaper in the UK is also saying the ice in the buried crater may be liquid. A very brief article, but they are quoting Professor John Guest of University College:

http://www.thesun.co.uk/article/0,,2-2005550842,00.html

I checked, and yes, John Guest is involved with MARSIS (hadn't heard his name before):

http://www.pparc.ac.uk/mars/bg_i_marsis.asp

I'm curious now; New Scientist and The Sun are quoting two MARSIS scientists, that there may be liquid water in the bottom of that subsurface crater, one in the UK and one in the US (JPL). William Johnson (re New Scientist) is the one at JPL, although Jeffrey Plaut (also with MARSIS at JPL), and Giovanni Picardi (MARSIS, in Italy) have been quoted as saying that no evidence for liquid water had been found yet (ESA press release and BBC News). So are both "liquid water" stories just misquotes, or are there just divided opinions within MARSIS? A misquote would be less likely, I would think, with New Scientist, than with The Sun, so I am thinking there are just various opinions at this point, until MARSIS can take another look.

Of course, as stated also, the main search for liquid water by MARSIS will begin later this winter / spring.

[Bob Shaw]

The Sun newspaper in the UK is also saying the ice in the buried crater may be liquid. A very brief article, but they are quoting Professor John Guest of University College...

[

FWIW, I've always felt that John Guest came down on the right side of most issues. The Sun 'newspaper', however, is about as reliable as those US supermarket thingies that report Elvis on Pluto - I'd go for a *quality* rubbish UK newspaper any day, like the Daily Sport!

Bob Shaw

[Guest_paulanderson_*]

Re my contention about making the critical distinction between the clay minerals and sulphates, both part of Mars' water story, Jean-Pierre Bibring, principal investigator for Omega on Mars Express, sums it up nicely in this new BBC News article (December 6, 2005):

http://news.bbc.co.uk/1/hi/sci/tech/4502018.stm

Quotes:

"Crucially, these are not the sulphate minerals seen by the US Mars rovers but a different class of hydrated minerals, known as phyllosilicates - more familiarly called clay minerals. In Bibring's opinion, it is far more likely that ExoMars will find evidence of life laid down in these rocks than if it were to look at the sulphates documented by the US vehicles. "Phyllosilicates trace the moment when liquid water was perennial and persistent - something not necessary to make sulphates. To make clay minerals requires long-standing bodies of water and [for life to form] you need that - at least with the experience we have from Earth." This puts Marwth Vallis and other clay locations - such as Arabia Terra, Terra Meridiani, Syrtis Major, and Nili Fossae - high on the list of possible ExoMars targets. And it pushes down the list the sulphate locations such Meridiani Planum and Gusev Crater currently being inspected by the US Mars rovers. Their sulphates were formed in acidic conditions - a challenging environment for any lifeform to evolve.

It is a point echoed last week by US rover scientist Dr Andrew Knoll of Harvard University. He observed: "Life that had evolved in other places or earlier times on Mars, if any did, might adapt to Meridiani conditions, but the kind of chemical reactions we think were important to giving rise to life on Earth simply could not have happened at Meridiani." Jean-Pierre Bibring says the instruments on ExoMars should be equipped to look for large carbon molecules in amongst the clays of Marwth Vallis as a possible signature of past life."

I'm glad to see at least BBC News and a handful of others are showing both sides of the equation. Daily Planet on Discovery Channel here in Canada also ran a piece yesterday on the new subsurface ice findings by Mars Express, which was good (and I like DP), but no mention yet of the clay mineral findings.

[JonClarke]

I agree, there is a tendency to draw far reaching conclusions from still minscule sets of data.

What is interesting to me is the increasing complexity of the story, and the diversity of aqueous environments being found.

There is an interesting paper in press with Earth and Planetary Science letters by Tosca and McLennan, on chemical divides in Martian brines (for those who have access) modelled for basaltic weathering There are five major end members suggested, one corresponds closely with what we see at Meridiani, and one with the salts in the Nakhlites.

Jon

[Guest_BruceMoomaw_*]

Since the ESA -- to my amazement -- seems to be serious about flying ExoMars (maybe serious enough to cancel BepiColombo for it), the obvious question is: should both it AND MSL be sent to phyllosilicate sites, or should one of them be sent to a different type of terrain, such as a Meridiani-type sulfate deposit? (A pretty strong case can be made, actually, that they SHOULD both go to diferent phyllosilicate sites.)

[edstrick]

Clearly, there needs to be close cooperation between ESA and NASA on picking rover sites. But given that both rovers are (I presume) being designed to go into smaller landing site footprints (that can fit in more complex terrain). As surface mineralogic mapping improves in resolution and mineral discriminability, it will be more and more likely we'll be able to target landing sites with primary target lithologies, like the clay minerals, and secondary targets nearby, perhaps younger sulfate deposits.

Opportunity's landing site is a good example of what would be a TERRIBLE site for an advanced rover. Once Oppy reaches Victoria crater, there's almost nowhere to go. Endless variations on dunes and etched terrain extending far beyond plausible rover traverse distances.

I don't know where the current "Terra Meridiani" deposits of phyllosilicates are, but one possibility might be the far northeast edge of Meridiani Sinus, where some of the fantastically etched multi-layered deposits of the "meridiani badlands" are being stripped off of old cratered terrain. If so, you could explore some of the old terrain's geology, and a fantastically better exposed sample of the younger deposits. (The old terrain's exposures might not be nearly as well "opened up" as in channels or chaotic terrain, though.)

[Guest_BruceMoomaw_*]

Well, keep in mind that the central goal of Martian exploration is still finding promising possible fossil beds -- and ancient clays from nonacidic water are the best candidate yet: much better than acid-produced sulfates. As Doug McCuistion said at the COMPLEX meeting, the strategy of trying to close in on the best places to look for Martian fossils as our top goal is producing huge amounts of non-biological scientific data about Mars as a side benefit -- whereas the reverse would not be true. (The major exceptions seem to be atmospheric studies and seismology, both of which are given an improved place in the latest NASA plan.)

[gpurcell]

Since the ESA -- to my amazement -- seems to be serious about flying ExoMars (maybe serious enough to cancel BepiColombo for it), the obvious question is: should both it AND MSL be sent to phyllosilicate sites, or should one of them be sent to a different type of terrain, such as a Meridiani-type sulfate deposit?  (A pretty strong case can be made, actually, that they SHOULD both go to diferent phyllosilicate sites.)

So that's the deal, then? I was reading the Bepi cancellation as evidence that ESA science was going to be slowly strangled....

[ljk4-1]

If they want to put human colonies on Mars, perhaps they should have rovers that focus on what resources are available to help them build structures and "live off the land" if possible.

http://www.marshome.org/building-the-base/

Then once a base or two are established, they can send out teams of geologists/paleontologists to look for fossils.