Alternate Theory for Meridiani Layering

[JonClarke]

I've got several good books on pyroclastics already. I probably don't need another one!<br /><br />I doubt if orbital remote sensing will help much at all. First, the dust covering will make identification tentative. Second, what we need is more stratigraphic sections that show the vertical and lateral successions. Mineralogy is of limited use in determining depositional environment.<br /><br />Ideally we need to complement the outcrop descriptions with samples for microcopic analyses. But I doubt that will happen in our life time.<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>

 

[fingle]

Thank You JonClarke for the clever re-write of whatever Tennison poem that came from.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>for my purpose holds To drive beyond the landing ellipse, and the etched terrain, until the rover dies.<p><hr /></p></p></blockquote><br /><br />That's great, and here's hoping there will be many more sols for both Spirit and Opportunity.<br /><br /><img src="/images/icons/smile.gif" /><br /> <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Glad you liked to, it was fun doing it. But the real genius is Tennyson. They don't have poets like him any more.<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>

 

[fingle]

I was hoping you would volunteer the name of the Tennyson poem which you paraphrased, so I guess I'm going to have to pry it out of you.<br /><br />We have our ways mr. JonClarke, and they are not pleasent. So I think you will tell me now before the unpleasentness has to begin, yes ?<br /><br />Really no kidding I tried for myself but I have already killed a couple of hours and I gave up after my browser crashed.<br /><br /><br />anyway, thanks<br /><br /><img src="/images/icons/smile.gif" /><br /> <div class="Discussion_UserSignature"> </div>

 

[telfrow]

John's not going to be around for a few days, so...<br /><br />It's from <i>Ulysses</i> by Alfred, Lord Tennyson. My personal favorite. In fact, the last line - "Made weak by time and fate, but strong in will to strive, to seek, to find, and not to yield." was my sig line here for quite a while.<br /><br />Here's the passage:<br /><br /><i>The lights begin to twinkle from the rocks;<br />The long day wanes; the slow moon climbs; the deep<br />Moans round with many voices. Come, my friends.<br />'T is not too late to seek a newer world.<br />Push off, and sitting well in order smite<br />The sounding furrows; for my purpose holds<br />To sail beyond the sunset, and the baths<br />Of all the western stars, until I die.</i> <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[fingle]

Thank You telfrow, <br /> I should have guessed that you would know. A few of your posts here came up while I was googleing around for the answer.<br /><br />thanks.<br /><img src="/images/icons/smile.gif" /><br /> <div class="Discussion_UserSignature"> </div>

 

[franontanaya]

Hi.<br /><br />I was thinking about the berries and remembered those round pyrites from my old minerals guide, so I did a search and found these pages. <br /><br />http://www.shale-mudstone-research-schieber.indiana.edu/pyrite_ooids.htm<br />http://www.shale-mudstone-research-schieber.indiana.edu/Winnipe_pyrite_ooids.htm<br /><br />Is that similar with the processes that formed Meridiani? The page talks about dessication and erosion, and growth of pyrite ooids by replacement on Chamosite ooids:<br /><br />http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_45099.htm<br /><br />Those have been found in crossbedded sediments.<br /><br />It doesn't seem an scenario too far away of Meridiani. Would those ooids grow differently at Mars? <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Sorry for the slow response top this, I forgot about it until just now.<br /><br />Most round pyrite bodies are concretions and thus probably analogous to those at Meridiani in terms of general precipitation mechanism, if not chemistry.<br /><br />Ooids are rounded grains formed by oscillatory motions in a subaqueous environment. They are extremely common in some limestones, e.g the Oolite of England, and can be seen forming in the Bahamas and the Persian Gulf, and elsewhere. They are less common in ironstones and silica deposits and very rare in sulphides. The Indiana examples are plausibly replacement of a previous iron silicate phase, while the Canadian examples are quite possibly primary. <br /><br />As for the Meridiani grains, I for one did think they might have been ooids quite early on.. The doublets and triplets is consistent with them forming this way (it excludes formation as accretionary lapelli, impact glasses, or impact spherules, BTW). However, ooids are concreated along sedimentary structures because they roll round on the sea (or lake) floor, or even, rarely, in some rivers. The Meridiani ones are evenly spaced through the rock, which is consistent with concretions.<br /><br />Hope this helps<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>

 

[3488]

Hi Jon Clarke & FranOntanaya,<br /><br />Found this nice terrestrial example of what you are talking about.<br /><br />Phosphatic ooids from Phosphoria formation, Montana. Individual ooids are about 1 mm across. <br /><br />Photo by Richard Gibson.<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]

Cool! Do you know if they are originally phosphate or if they have been phosphatised?<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 />They were originally Phosphate.<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>