Mars Water Debate Still Rages

[alexblackwell]

Since the original thread was lost in the SDC meltdown, I'll start a new one by noting a few recently published peer-reviewed science papers:<br /><br />From the July 2, 2004 issue of <i>Science</i>:<br /><br />Evidence for Precipitation on Mars from Dendritic Valleys in the Valles Marineris Area <br />Nicolas Mangold, Cathy Quantin, Véronique Ansan, Christophe Delacourt, and Pascal Allemand <br /><i>Science</i> <b>305</b>, 78-81, (2004).<br />Abstract<br />Supporting Online Material<br /><br />Signs of Ancient Rain May Stretch Mars's Balmy Past<br />Richard A. Kerr<br /><i>Science</i> <b>305</b>, 26, (2004).<br />Summary<br /><br />Published online July 15, 2004 in <i>JGR-Planets</i>:<br /><br />Ghatan, Gil J.; Head, James W., III<br /><b>Regional drainage of meltwater beneath a Hesperian-aged south circumpolar ice sheet on Mars</b><br />J. Geophys. Res., Vol. 109, No. E7, E07006<br />10.1029/2003JE002196<br />15 July 2004<br />Abstract<br /><br />There are also a few interesting Mars water-related articles in the August 2004 issue of the journal <i>Icarus</i>.<br />

 

[voyagerwsh]

Great to see old threads back! Thanks, AlexBlackwell.<br /><br />Michael Carr's topic of "Water on Mars" in the Planetary Society's <i>The Planetary Report</i> was probably his strongest wordings on the liquid water on mars that I have learned from.

 

[alexblackwell]

<i>Michael Carr's topic of "Water on Mars" in the Planetary Society's The Planetary Report was probably his strongest wordings on the liquid water on mars that I have learned from.</i><br /><br />Yeah, I agree his article in the May/June 2004 issue of The Planetary Report was very good, which is no surprise given that there is no one better qualified to discuss "water on Mars."<br />

 

[thechemist]

It was about time, thanks Alex !<br />And good timing with today's high Cl- announcement deep in Endurance. <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[thechemist]

In the following article the authors claim that their experiments agree with the S/Cl ratio of 5 measured in both the Viking and the Pathfinder sites. Oceans on earth have S/Cl values lower than 1. However in today's JPL S/Cl graph of deep layers in Endurance, there is no scale on the graph !<br />It would be interesting to find out the actual S/Cl value measured, unless we have to wait for the paper for that <img src="/images/icons/smile.gif" /><br /><br />The article has a detailed introduction and provides literature on possible mechanisms of salts formation on Mars.<br />Many thanks to Alex for pointing to this issue of Icarus. You destroyed my sleep Alex, shame on you <img src="/images/icons/smile.gif" /><br /><br />Icarus , Volume 170, Issue 2 , August 2004, Pages 404-423.<br />Laboratory simulations of Mars aqueous geochemistry <br />Mark A. Bullock, Jeffrey M. Mooreb and Michael T. Mellonc .<br /><br />Here is the abstract for those without access to ScienceDirect:<br /><br /><font color="yellow">Abstract<br />We report on laboratory experiments in which we allowed an SNC-derived mineral mix to react with pure water under a simulated Mars atmosphere for 7 months. These experiments were performed at one bar and at three different temperatures in order to simulate the subsurface conditions that most likely exist where liquid water and rock interact on Mars today. The dominant cations dissolved in the solutions we produced, which may be characterized as dilute brines, are Ca2+, Mg2+, Al3+, and Na+, while the major anions are dissolved C, F-, SO4(2-) and Cl-. Typical solution pH was in the range of 4.2–6.0. Abundance patterns of elements in our synthetic sulfate–chloride brines are distinctly unlike those of terrestrial ocean water or continental waters, however, they are quite sim</font> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[alexblackwell]

<b>Carbonates in ALH 84001: Part of the Story of Water on Mars</b><br /><br />--- The study of multi-generational carbonate assemblages in Martian meteorite ALH 84001 reveals a complex history of crystal formation, growth, and alteration.<br /><br /><i><b>Written by Catherine M. Corrigan</b></i><br />Smithsonian Institution, National Museum of Natural History<br />posted July 1, 2004<br />

 

[alexblackwell]

<i>Icarus , Volume 170, Issue 2 , August 2004, Pages 404-423. <br />Laboratory simulations of Mars aqueous geochemistry <br />Mark A. Bullock, Jeffrey M. Mooreb and Michael T. Mellonc</i><br /><br />I agree that it's a pretty interesting paper, with a good introductory section giving the context of the discussion. A key passage underscored one of the glaring science gaps in Mars geology:<br /><br />"It is one of the great frustrations of Mars surface science that no mineralogical analysis has been possible to date, and few trace element compositions have been determined. This may change with more sophisticated experiments on landers, such as Mössbauer and Raman spectroscopy, X-ray diffraction, and other analytic techniques."<br /><br />It's hard to believe but the Mössbauer data from MER, limited though they are to Fe-bearing minerals, offer the first chance for <i>in situ</i> Martian mineralogical analysis. Note that a Raman spectrometer was a part of the original Athena science suite but was dropped when Squyres et al. had to descope the payload for MER.

 

[thechemist]

Carbonates in ALH 84001: Part of the Story of Water on Mars <br />Written by Catherine M. Corrigan <br /><br />A nice article Alex.<br />Quote :<font color="orange"> The inconsistency between photogeological and rock data needs to be reconciled before we understand the details of the history of water on Mars.</font><br /><br />Two of the questions remaining open:<br />a. Where are the martian carbonates ?<br />b. Was ALH84001 the only martian rock holding an umbrella ?<br /><br />Until sample return missions are reality, we will have to work with what we get from the MERs in order to reveal parts of the water story and mineralogy. <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[alexblackwell]

Vernadsky Institute - Brown University Microsymposium 40<br />Topics in Comparative Planetology<br />October 11-13, 2004 Vernadsky Institute, Moscow, Russia

 

[alexblackwell]

Workshop on Low-Frequency Radar Investigations of Planetary and Terrestrial Environments<br />February 7–10, 2005, Houston, Texas

 

[alexblackwell]

Published online July 8, 2004 in <i>Geophysical Research Letters</i>:<br /><br />Miyamoto, Hideaki; Dohm, James M.; Baker, Victor R.; Beyer, Ross A.; Bourke, Mary<br /><b>Dynamics of unusual debris flows on Martian sand dunes</b><br />Geophys. Res. Lett., Vol. 31, No. 13, L13701<br />10.1029/2004GL020313<br />08 July 2004<br />Abstract

 

[thechemist]

The BBC article you linked <b> started </b> the whole ammonia discussion and assorted controversy on Thursday July 15.<br />How could this have been discussed before the SDC "Big Rip" ? <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[blairf]

The interview with Formisano that started the previous debate can be found here<br /><br />http://www.earthfiles.com/news/news.cfm?ID=707&category=Science<br /><br />It was back in April and we did have a moderately involved discussion on these boards (c30 posts IIRC).<br /><br />

 

[alexblackwell]

Thanks for tip on the article. It is interesting, even considering that it was written by David Chandler ;-)

 

[alexblackwell]

From the August 2004 issue of the journal <i>Geology</i>:<br /><br /><b>Global geologic context for rock types and surface alteration on Mars</b><br />Michael B. Wyatt, Harry Y. McSween Jr., Kenneth L. Tanaka and James W. Head III<br /><i>Geology</i> <b>22</b>, 645–648, (2004).<br />Abstract

 

[alexblackwell]

<i><b>Global geologic context for rock types and surface alteration on Mars </b><br />Michael B. Wyatt, Harry Y. McSween Jr., Kenneth L. Tanaka and James W. Head III <br />Geology <b>22</b>, 645–648, (2004).</i><br /><br />An ~372 Kb PDF reprint is now available.

 

[alexblackwell]

Published online today in <i>Geophysical Research Letters</i>:<br /><br />Bullock, Mark A.; Moore, Jeffrey M.<br /><b>Aqueous alteration of Mars-analog rocks under an acidic atmosphere</b><br /><i>Geophys. Res. Lett</i>., Vol. 31, No. 14, L14701<br />10.1029/2004GL019980<br />22 July 2004<br />Abstract

 

[alexblackwell]

Published online today in <i>Geophysical Research Letters</i>:<br /><br />Harrison, K. P.; Grimm, R. E.<br /><b>Tharsis recharge: A source of groundwater for Martian outflow channels</b><br /><i>Geophys. Res. Lett</i>., Vol. 31, No. 14, L14703<br />10.1029/2004GL020502<br />24 July 2004<br />Abstract

 

[dtb99]

Alex,<br /><br />Thanks for the link to the Wyatt, et. al., preprint. Wow, one of those great, short papers that puts several lines of evidence together to make a compelling case. I suspect it will be well-cited.<br /><br />One intriging finding they do not mention is the global dust distribution: their graphs show a strongly bimodal latititude distribution of terrain with a heavy dust mantle, centered on 40N and 40S, with virtually all the dust-heavy terrain falling between 30 and 50 latittudes in either hemisphere. The data isn't new, but I'd never seen anyone display the TES results by latittude like that. Is this something others have mentioned?<br /><br />Sure looks like a large-scale climate effect, like Earth's desert bands around 25-35 degrees. I wonder if that's a result that current Mars climate models predict, and, I wonder how (or if) those bands move in response to obliquity changes or other major climate changes?<br /><br />Again, thanks for all the links!

 

[alexblackwell]

Probe maps water vapour on Mars<br />By Paul Rincon <br />BBC News Online science staff, in Paris<br />Last Updated: Monday, 26 July, 2004, 13:28 GMT 14:28 UK

 

[alexblackwell]

Published online today in <i>JGR-Planets</i>:<br /><br />Bruno, B. C.; Fagents, S. A.; Thordarson, T.; Baloga, S. M.; Pilger, E.<br /><b>Clustering within rootless cone groups on Iceland and Mars: Effect of nonrandom processes</b><br /><i>J. Geophys. Res</i>., Vol. 109, No. E7, E07009<br />10.1029/2004JE002273<br />27 July 2004 <br />Abstract

 

[alexblackwell]

<i>One intriging finding they do not mention is the global dust distribution: their graphs show a strongly bimodal latititude distribution of terrain with a heavy dust mantle, centered on 40N and 40S, with virtually all the dust-heavy terrain falling between 30 and 50 latittudes in either hemisphere. The data isn't new, but I'd never seen anyone display the TES results by latittude like that. Is this something others have mentioned?</i><br /><br />I'm not sure I follow exactly what you're saying but, if I'm not mistaken, TES thermal inertia maps were published back in 2001 that have shown these dusty regions, which also have an interesting correlation to the "slope streaks."

 

[exoscientist]

The relationship between high water vapor and high hydrogen from the gamma ray spectrometer suggests this water in near equatorial regions is in free form, not chemically bound form, that could melt from ice to liquid or condense from vapor to liquid at the right temperatures.<br /><br /><br /> Bob Clark <div class="Discussion_UserSignature"> </div>

 

[dtb99]

<br />My point was just that the areas with thick dust mantles (according to TES) fall in narrow bands of lattitude: 30 to 50 degrees S, or 30-50 deg N, not in the tropics or further towards the poles. <br /><br />That sort of distribution seems like it would be climate related, so I was wondering if there were any models yet that explain why we currently see dust deposition concentrated in the mid-latitudes.<br /><br />

 

[alexblackwell]

<i>My point was just that the areas with thick dust mantles (according to TES) fall in narrow bands of lattitude: 30 to 50 degrees S, or 30-50 deg N, not in the tropics or further towards the poles. <br /><br />That sort of distribution seems like it would be climate related, so I was wondering if there were any models yet that explain why we currently see dust deposition concentrated in the mid-latitudes.</i><br /><br />OK, now I see where you're headed. Head <i>et al</i>. [2003] interpreted these "thick dust mantles" primarily as "a metres-thick but partially degraded and discontinuous surface deposit...limited to the 30 degree – 60 degree north and south latitude zone....This deposit [is] interpreted as a recent, formerly ice-rich dust mantle that originated as a thin blanketing airfall layer and [is] now undergoing dissection and removal."<br /><br />References:<br /><br />Baker, V.R., Icy martian mysteries, <i>Nature</i> <b>426</b>, 779-780, (2003).<br />598 Kb PDF reprint<br /><br />Head, J.W., <i>et al</i>., Recent ice ages on Mars, <i>Nature</i> <b>426</b>, 797-802, (2003).<br />1.23 Mb PDF reprint<br /><br />Mars in an ice age: The red planet before the present interglacial<br /><br />Landscapes on buried glaciers in Antarctica's dry valleys help decipher recent ice ages on Mars