Good summaries and reviews of the results of the MER missions.

[exoscientist]

Mostly about the Spirit mission:<br /><br />Remote Sensing Tutorial Page 19-13a<br />Missions to Mars during the Third Millenium<br />http://rst.gsfc.nasa.gov/Sect19/Sect19_13a.html<br /><br />and:<br /><br />Remote Sensing Tutorial Page 19-13b<br />http://rst.gsfc.nasa.gov/Sect19/Sect19_13b.html<br /><br />which is mostly about the Opportunity mission.<br /><br /> This second also has a link to a report that might offer an explanation for the lack of carbonates at Meridiani:<br /><br />ACID SEDIMENTARY ENVIRONMENTS ON MARS?: POSSIBLE TERRESTRIAL ANALOGS<br />http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_36936.htm<br /><br /><br /><br /> Bob Clark<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Much as I approve of Australian analogues for martian environments I have to give a word of caution about using the acid lakes of South Australia. <br /><br />These lakes (Lock Claypan, Pinjarra Lakes etc.) and similar features in Western Australia (Lakes Glimore, Dundas) are typically thought to be acidic because of ferrolysis of iron silicate minerals (e.g. amphiboles, chlorite) in a deeply weathered environment. However all the examples I know in WA and SA (including the examples above) occur over thick successions of sulphide and organic rich sediment, and it is possible that the acid groundwater is from natural sulphide oxidation. What ever the cause the result is certainly impressive, acid (pH <3 waters covering areas of 100's of km2 and depositing alunbite and jarosite. Interestingly with respect to the carbonate issue, these lakes occur in depressions sunk into a calcreted landscape, so you have a carbonate rich soil elevated 1-5 m above and acidic watertable that crops out in the (mostly dry) lake beds.<br /><br />This is an area that needs a lot more research, not just from a Mars analogue perspective, but of what it can tell us about sedimentary diagenesis and because of the implications for land management (salinisation, acidification, inland acid sulphate soils) and mineral exploration (heavy metal ion mobilisation) in those areas.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[3488]

Hi Bob & Jon.<br /><br />I have only literally just seen these very interesting posts.<br /><br />Since it has been approx three years ago since you both discessed this, has there<br />been any further developments.<br /><br />I agree totally. This type of research has many knock on effects.<br /><br />Also has anything that Spirit & Opportunity observed, been able to correlate / refute<br />the southern Australian analogues?<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[MeteorWayne]

That's funny! JonClarke was only a molecule back then <img src="/images/icons/smile.gif" /><br /><br />A mere sneeze might have blown him away <img src="/images/icons/laugh.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[3488]

I know MeteorWayne.<br /><br />it is a long time ago, but I had only just seen this & thought it might be worth bringing back<br />if the MERs have been able to further this, since then?<br /><br />Given the fact that both MERs have uncovered very different water stories & how<br />they might relate / differ to the examples given by Jon Clarke in Australia.<br /><br />This is very interesting.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[JonClarke]

It really is a blast from the past. Old school photos if you like! <img src="/images/icons/smile.gif" /><br /><br />Since then I have come to suspect that these acid lakes may well be due to oxidation of sulphides as well as/instead of silicates. I don't know if this is relevant to Mars or not. <br /><br />But I am a little bit sceptical of the "everything is acid on Mars" band wagon. There is some evidence of acidity, but whether this means everything was acid I don't think so. On Earth, acid solutions are quite rapidly bufferred by reactions with rocks to more neutral conditions. This should happen on Mars too, unless something is happening to maintain acidity.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[3488]

Hi Jon,<br /><br />Welcome back.<br /><br />Did you have a good time? Did anything interesting?<br /><br />Yes that is true.<br /><br />I take it that salts on Mars would raise the PH in any ancient acid lakes, as well as alkaline <br />chemistry in the silicate rocks?<br /><br />I would very much doubt that biological processes would have done so, even if life <br />did get started, I doubt it evolved past the Amoeba stage, before dying out.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[exoscientist]

Here's an article by space reporter Bruce Moomaw on the Mars "caves" that also summarizes the theory that acids on the surface are responsible for the lack of carbonates on Mars:<br /><br />Down The Hatch On Mars.<br />by Bruce Moomaw<br />Cameron Park CA (SPX) Jun 12, 2007<br />"Mars has no limestone beds, and indeed seems to have no surface carbonates at all -- but it does appear to have some inorganically formed carbonate minerals buried underground.<br />"And, in fact, the reason that it has no surface carbonates, as we now know, is precisely because after its initial thick atmosphere disappeared, the planet's lack of an ozone layer meant that solar ultraviolet light could all the way down to the surface and set off reactions in the sulfurous gases vented from its volcanoes to form large amounts of sulfuric acid."<br />http://www.marsdaily.com/reports/Down_The_Hatch_On_Mars_999.html<br /><br /> He mentions the interesting idea that the great amount of radiation reaching the surface is what causes the acids on the surface of Mars.<br /> But he also mentions there are likely carbonate minerals underground. Is he saying this because of carbonates found in Mars meteorites?<br /><br /><br /> Bob Clark <div class="Discussion_UserSignature"> </div>