Did Mars cool more slowly than first thought?

[jaxtraw]

"Btw isn't there a similar issue with Al26?"<br /><br />Do you mean regarding early solar system abundance?

 

[3488]

Surely Al26 would have been in greater abundance than now, in the early solar system.<br /><br />I do not see a problem there.<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>

 

[3488]

Thanks Jon, <br /><br />Perhaps I am being hung up too much on semantics. A molten silicate surface is of <br />course a Magma Ocean. Smaller areas are Lava Lakes, & lava is magma erupted by volcanoes.<br /><br />Jon, in your OWN personal opinion, do you think there is active volcanism today on Mars & / or Mercury?<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>

 

[jaxtraw]

I was hoping H2Ouniverse would clarify the issue he's referring to <img src="/images/icons/smile.gif" />

 

[bguth]

I think related: <br /><br />Where did all of that Mars salt go? Or didn't Mars have hardly any salt to start off with? <br />-- Brad Guth

 

[JonClarke]

<i>A larger proportion of heavier elements (Pyrites in this case) is present on/near the surface compared to Earth - around 15% of total soil composition, as opposed to about 5% here.</i><br /><br />Where are you getting this from? Traces of pyrite (and other sulphides) have been found in SNCs. No my knowledge no sulphides have been identified by any lander.<br /><br />Sulphides do not make up 5% of the Earth's surface materials, genereally it is loess than 1%.<br /><br />I am all confused!<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>

 

[JonClarke]

<i>Jon, in your OWN personal opinion, do you think there is active volcanism today on Mars & / or Mercury?</i><br /><br />I found the evidence presented by Nerkum and others using MEx images for 2 My or younger lava flows on Olympus Monds compelling. Since these volcanic edifices are 100's of Ma old, i think they are still active.<br /><br />Mercury, I don't know. the images i have seen suggest a very old surface like the Moon. Like the Moon i suspect it's dead, apart from a little occasional outgassing, perhaps. But we haven't seen all of thesurface yet. So who knows?<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>

 

[JonClarke]

<i>Where did all of that Mars salt go? Or didn't Mars have hardly any salt to start off with?</i><br /><br />I don't understand your question. We have seen lots of sulphate salts at Meridiani, and indications of it elsewhere. <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>

 

[Swampcat]

Hey, Brad.<br /><br />Weren't you banned from here some time ago? <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>

 

[yevaud]

<i>Where are you getting this from?</i><br /><br />Er, every book on Planetary Science used in every University around the world, for the last 50 years... <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[bguth]

Simply quantify Mars salt, or is that asking too much?<br /><br />How much of the Mars surface that has been so nicely explored and/or probed to death thus far contains whatever sodium minerals or the remains of old sea salt?<br /><br />Shouldn't Mars by rights of orbital/planetology physics have a greater proportion of whatever salts than Earth?<br /><br />If not, then why not? <br />-- Brad Guth

 

[h2ouniverse]

Yes, indeed I meant regarding initial abundance, that is not well known . Al26 is short-lived and should decay quickly.<br />I could see a parallel with the issue with the Samarium. And the question of the "reset clock".<br />Some speculate too on deuterium and O18 abundances.<br /><br />There seems to be many questions on initial abundances (and may be some facility for some theoreticians?).<br /><br />Regards.<br />

 

[sponge]

<font color="orange">I found the evidence presented by Nerkum and others using MEx images for 2 My or younger lava flows on Olympus Monds compelling. Since these volcanic edifices are 100's of Ma old, i think they are still active. <br /><br /><font color="white">That is a very interesting statement Jon, I hope we can prove this theory in the not too distant future, if Mars still has some volcanic activity taking place, I suppose it wouldn’t be too far fetched to conclude that there would be the presence of a few subterranean liquid water tributaries, maybe with the presence of bacterial life, not including the bacterial life, do you think in your opinion there might be a chance of large subterranean aquifers, I know this has probably been belted out before, but I haven’t heard anyone here say that they think there might still be some activity.</font></font> <div class="Discussion_UserSignature"> <p><em><u>SPONGE</u></em></p> </div>

 

[JonClarke]

There has been another paper recently, saying much the same thing. it was published in JGR (planets) unfortunately, which I don't easily have access to.<br /><br /><br />Jon<br /> <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>

 

[JonClarke]

<i>Er, every book on Planetary Science used in every University around the world, for the last 50 years... </i><br /><br />None of the ones I have read mention 15% pyrite on the surface of Mars, or an average of 5% on the surface of the Earth for that matter.<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>

 

[JonClarke]

Sorry for the slow reply to this question:<br /><br /><i>What I do not understand is how scientists can claim that the clock gets reset each time that melting occurs.</i><br /><br />It depends on the "clock" used as to how the resetting works. <br /><br />Basically as a radioactive parent istope decays at a known rate it produces a daughter product at a known rate. Provided the initial quantities of the parent are known and there has been no subsequent loss or addition of either daughter or parent (we can determine this by various ways) you can use the known decay constant and the measured daughter/parent ratio to determine age. <br /><br />Ideal minerals are those which contain negligible amounts of the daughter to start with and which do not readily lose or gain either daughters or parents. <br />I will give two simple examples which also happen to be the ones I know best.<br /><br />For uranium-lead, an ideal mineral for dating is zircon. It's lattice is such that it readily traps uranium atoms, but excludes lead. Zircon is also unreactive and so uranium does not readily diffuse out - lead is extremely unlikely to diffuse in. So any uranium in zircon is will have been trapped there when the zircon crystallised and any lead would have formed by decay of that uranium. There are ways of cross checking this of course. If the rock is heated so much that the zircon melts, the uranium and lead are spread throughout the magma. When this cools next zircons form trapping uranium but not lead. Thus the clock is "reset".<br /><br />Radioactive potassium decays into argon. When potassium rich minerals (like micas and feldspars) form they trap very little if any argon from the environment. However argon that forms by decay after the crystal has formed is trapped by the crystal lattice. Tiny amounts of argon can sometimes be absorbed from the environment, these will give supriously old dates for young rocks dated by this means. However, this adsorbed argon can be identified bec <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>

 

[yevaud]

The one's I referenced did. Though they are, of course, a number of years out of date at this point, that was commonly held to be accurate when they were published. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[robnissen]

<font color="yellow"><br />For uranium-lead, an ideal mineral for dating is zircon. It's lattice is such that it readily traps uranium atoms, but excludes lead. Zircon is also unreactive and so uranium does not readily diffuse out - lead is extremely unlikely to diffuse in. So any uranium in zircon is will have been trapped there when the zircon crystallised and any lead would have formed by decay of that uranium. There are ways of cross checking this of course. If the rock is heated so much that the zircon melts, the uranium and lead are spread throughout the magma. When this cools next zircons form trapping uranium but not lead. Thus the clock is "reset". <br /><br />Radioactive potassium decays into argon. When potassium rich minerals (like micas and feldspars) form they trap very little if any argon from the environment. However argon that forms by decay after the crystal has formed is trapped by the crystal lattice. Tiny amounts of argon can sometimes be absorbed from the environment, these will give supriously old dates for young rocks dated by this means. However, this adsorbed argon can be identified because of its isotope ratios and can driven off by gentle heating. For older rocks the amount of radiogenic argon overwhelms the trace adsorbed and so this can be effectively ignored. When the rock is strongly heated or even melted, the radiogenic argon is also driven off into the volatile phase. When the rock cools or the magma recrystallises, the potassium-bearing minerals start accumulating argon again, and the clcok is reset. <br /></font><br /><br />Thanks for the brief tutorial on dating, that was informative. I knew the general principles of resetting the "clocks" but your explanation made it much clearer to me. Thx.<br /><br />

 

[JonClarke]

Maybe you mean iron, rather than pyrite? If so, you are correct.<br /><br />Lodders and Fegley's "The Planetary Scientist's Comapnion" list the SNCs (which may not be that representative) as having 14-31% Fe, while the earth's crustal average is 4-5% (oceanic crust 8%). <br /><br />The iron would be minerals like olivine, pyroxene, and magnetite. SNC meteorites are listed as having only rare pyrite. Haematite and maghaemite are reported spectroscopically from the surface.<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>

 

[JonClarke]

Glad to help! <img src="/images/icons/smile.gif" /> <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>

 

[MeteorWayne]

I agree, Jon, Thanx!!<br /><br />Although I knew all that, your clear statement crystalized (pun intended) the concept in my mind. The difference between "understand" and "grok".<br /><br />Appreciate it.<br /><br />Wayne <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>

 

[yevaud]

Must've read the thing, but thought "Pyrites." <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[billslugg]

Jon<br />Thanks for the explanation! It makes sense now. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[JonClarke]

Very iron-ic<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>

 

[bearack]

From Andrew:<br />“That is correct, the magnetosphere, deflects the solar wind, thus preventing it from <br />eroding the martian atmosphere into space. When the magnetosphere collapsed, the <br />atmosphere was in a battle against solar wind, through replenishment from volcanoes. “<br /><br />Question, how could the magnetosphere collapse? I think this would be very pertinent information for also the survival of Earth, considering the importance of the Magnetosphere.<br /> <div class="Discussion_UserSignature"> <p><br /><img id="06322a8d-f18d-4ab1-8ea7-150275a4cb53" src="http://sitelife.space.com/ver1.0/Content/images/store/6/14/06322a8d-f18d-4ab1-8ea7-150275a4cb53.Large.jpg" alt="blog post photo" /></p> </div>