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Mars - Concretions or Secretions?
March 12, 2004
Please feel free to publish your future Mars geology or biology retractions here. http://qt.exploratorium.edu/mars/opp...MP2937M2M1.JPG Thomas Lee Elifritz http://elifritz.members.atlantic.net |
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Mars - Concretions or Secretions?
Thomas Lee Elifritz wrote:
March 12, 2004 Please feel free to publish your future Mars geology or biology retractions here. Okay, I haven't even made up any crackpot theories yet. But I'll retract them right now. ;-) |
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Mars - Concretions or Secretions?
"Thomas Lee Elifritz" wrote in message om... March 12, 2004 Please feel free to publish your future Mars geology or biology retractions here. Have you seen the pic of the interior of the Spirit crater? Spectacular! If you look at the walls of the crater along the right side of the pic, you'll see they're covered by rocks evenly as one would expect. But the left opposing and ...darker..crater wall is entirely different. Hardly a rock to be seen on the wall or below on the crater floor. And the dark opposing wall is also clearly rippled. It must be a sheet of cemented dunes made of spheres. So the rock face above the rippled wall is certainly much like the crusted Opportunity outcrop. Likely much older and more weathered though. But a large reef still! It's also becoming clear that the dark/lite rocks show that this was a sea that emptied quickly, like a dam burst. The rocks were fully coated by the ripples, then washed half off by the fast flowing water. This crater will be just a tease though, compared to the large Opportunity crater. What a great adventure this is. Jonathan s http://qt.exploratorium.edu/mars/opp...MP2937M2M1.JPG Thomas Lee Elifritz http://elifritz.members.atlantic.net |
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Mars - Concretions or Secretions?
"Doug..." wrote in message ... In article , says... snip Have you seen the pic of the interior of the Spirit crater? Spectacular! If you look at the walls of the crater along the right side of the pic, you'll see they're covered by rocks evenly as one would expect. But the left opposing and ...darker..crater wall is entirely different. Hardly a rock to be seen on the wall or below on the crater floor. And the dark opposing wall is also clearly rippled. It must be a sheet of cemented dunes made of spheres. Nothing like the Meridiani spherules has been found in Gusev. Basaltic pebbles, yes. Spherules, no. Not yet. I bet you money that on the floor of the Spirit crater spheres will be found. I'd be a LOT more willing to bet that the dune ripples in Bonneville Crater are just that -- sand dune ripples. Made of the dust that has accumulated in the crater over the millennia, dropped there by wind and sandstorm. Not likely made of spherules at all. I'd wait until something resembling the Meridiani spherules are actually observed in Gusev before making THAT assumption. If the Opportunity site suffered a large flood, the soil, spheres and all would be washed away. And only the underlying rocks and cemented buried dunes would be left. That is what we are seeing at the Spirit site. But the life that existed at both sites are the same. There will be spheres found at the Spirit site. The photos make clear the Spirit crater dunes are water features. The loose sand and soil long ago was washed away. Jonathan s So the rock face above the rippled wall is certainly much like the crusted Opportunity outcrop. Likely much older and more weathered though. Again, I doubt it. I don't see anything like the slabby, layered characteristics of the Meridiani outcrop in the Bonneville Crater images. Just a regular rock population, no particular layering evident in the rocks themselves. And the rocks are almost definitely of the same type and composition as the rocks on the rim, that Spirit will be examining over the next week or so. Those look exactly like the other basaltic rocks that Spirit has been looking at all over the Gusev site, so while it's a disappointment to those looking for lacustrine materials in Gusev, it begins to appear that the rock layers exhumed at Bonneville are all volcanic basalts. Of course, we'll know better when they get a full set of mini-TES observations of the crater interior, RAT some of the rocks on the rim, and take APXS and Mossbauer readings of the rocks and soils on the rim. We'll have some results from those activities in a week or so, probably. I'm really looking forward to seeing if there's any compositional differences between the rocks at the rim and those out on the plains, because the rim rocks ought to have been blasted from the deepest level of the crater, and thus represent the rocks lying that far below the surface of the rest of the plains. But a large reef still! Unlikely, just as your reef explanation for the Meridiani outcrop is extremely unlikely. I'm not ruling it out, but I still think it's unlikely. snip What a great adventure this is. With that sentiment, I completely agree! What a great time to be alive. Doug |
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Mars - Concretions or Secretions?
"jonathan" skrev i en meddelelse ... snip speculation The photos make clear the Spirit crater dunes are water features. The loose sand and soil long ago was washed away. We may argue about the origin of the spheres, but you owe us a through explanation for the above statement. http://www.msss.com/mars_images/moc/themes/DUNES.html Carsten |
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Mars - Concretions or Secretions?
"Carsten Troelsgaard" wrote in message . .. "jonathan" skrev i en meddelelse ... snip speculation The photos make clear the Spirit crater dunes are water features. The loose sand and soil long ago was washed away. We may argue about the origin of the spheres, but you owe us a through explanation for the above statement. Don't hold your breath waiting for an explanation. Especially a physical one. You can't squeeze blood from a stone. He can't give what he hasn't got. http://www.msss.com/mars_images/moc/themes/DUNES.html Carsten |
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Mars - Concretions or Secretions?
"Chosp" skrev i en meddelelse news:C8B5c.84889$h23.52982@fed1read06... Don't hold your breath waiting for an explanation. Especially a physical one. You can't squeeze blood from a stone. He can't give what he hasn't got. Well, as a mathematician he may give us a lesson in biology - let's see if he up to give us one in geology. Carsten |
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Mars - Concretions or Secretions?
"Carsten Troelsgaard" wrote in message . .. "Chosp" skrev i en meddelelse news:C8B5c.84889$h23.52982@fed1read06... Don't hold your breath waiting for an explanation. Especially a physical one. You can't squeeze blood from a stone. He can't give what he hasn't got. Well, as a mathematician he may give us a lesson in biology - let's see if he up to give us one in geology. Except that he is not a mathematician. He doesn't even pretend to be one very well. |
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Mars - Concretions or Secretions?
"Carsten Troelsgaard" wrote in message . .. "jonathan" skrev i en meddelelse ... snip speculation The photos make clear the Spirit crater dunes are water features. The loose sand and soil long ago was washed away. We may argue about the origin of the spheres, but you owe us a through explanation for the above statement. Do you really think this pic shows wind blown dunes? Then why does the dune define a line precisely where water would stand were it filled? Why is the dune darker on the wall then on the floor? There is clearly a difference between the dune on the wall and on the floor, if wind and dust were the cause of both then there shouldn't be such a well defined line separating the two. Your wind is very selective. And your dust clings very well to the side of a steep crater wall. http://marsrovers.jpl.nasa.gov/galle...0P2285R7M1.JPG And in this picture there's a rather flat dune, are you saying the wind blew the rocks away? Where did they go? They clearly sank in the mudflat, which means that dune formed when water was still there. And it's stayed there since. Wind blown dunes are transient features that come and go. http://marsrovers.jpl.nasa.gov/galle...0P1943R0M1.JPG And in this pic the rock appears to be lying on top, why didn't the wind blown dust form around the rock, or fill in underneath it? Shouldn't the dust be lying up against the rock? http://marsrovers.jpl.nasa.gov/galle...P2515R1M1.HTML And it's clear the dark portions of the rock are continuous with the dunes. Is this rock half covered with dark dust, or half covered with lite dust? And explain how dust can define such a fine line. http://marsrovers.jpl.nasa.gov/galle...1P2433R1M1.JPG The dark and lite dust seems rather selective http://marsrovers.jpl.nasa.gov/galle...P2313L6M1.HTML http://marsrovers.jpl.nasa.gov/galle...0P2530R1M1.JPG There's no way wind did this, the segregation of the rocks by size can only be done by water. Have you ever been to a beach? http://marsrovers.jpl.nasa.gov/galle...9P2213L6M1.JPG http://www.msss.com/mars_images/moc/themes/DUNES.html Carsten |
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