Home, Sweet Home, Dream becomes Reality |
Home, Sweet Home, Dream becomes Reality |
Feb 10 2006, 12:20 PM
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#151
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Senior Member Group: Members Posts: 2488 Joined: 17-April 05 From: Glasgow, Scotland, UK Member No.: 239 |
QUOTE (tdemko @ Feb 10 2006, 02:38 AM) That would be my take for the original deposit. Although, I'm not sure what the original grain size may have been...dust/silt or sand. I haven't yet got my earth-centric mind wrapped around Martian atmospheric pressures, wind speeds, and gravity and how they affect sediment transport. From what we've seen so far, it doesn't look like there are any features that had to have been water lain. However, I think that there was a subsequent groundwater/meteoric water-mediated alteration event to lithify the eolian material. Yes, *something* must have persuaded the dusty stuff to turn solid, whether or not the original deposition was into water or a smidgeon of water came later. In any case, nice tasty acidic water, loaded with salts would bind the essentially zero-strength debris into layered rock (and, once the water dries out the mineralised outer skin would be tough, until eroded away and the softer interiors revealed). Perhaps a test would be to look for a physically cracked-open rock which has been preserved from weathering by some chance and to examine the 'inside' vs the 'outside.... Bob Shaw -------------------- Remember: Time Flies like the wind - but Fruit Flies like bananas!
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Feb 10 2006, 12:30 PM
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#152
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Senior Member Group: Moderator Posts: 4279 Joined: 19-April 05 From: .br at .es Member No.: 253 |
This panorama should be quite impressive at the end!
Currently almost all of sol 748's 6x3 frames have been downlinked -- L7R1 only, the "color" should be waiting on the priority queue -- and more shots are planned for tosol. CODE 749 p2273.05 30 30 0 0 2 62 pancam_gibson_top_5cx1r_L257R127 749 p2274.05 66 0 0 66 2 134 pancam_gibson_left_11_pos_L257R127 Doug, I guess "a little bird" told you about it. Another "preview" (at half-size). |
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Feb 10 2006, 12:38 PM
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#153
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
QUOTE (Tesheiner @ Feb 10 2006, 07:30 AM) This panorama should be quite impressive at the end! Currently almost all of sol 748's 6x3 frames have been downlinked -- L7R1 only, the "color" should be waiting on the priority queue -- and more shots are planned for tosol. CODE 749 p2273.05 30 30 0 0 2 62 pancam_gibson_top_5cx1r_L257R127 749 p2274.05 66 0 0 66 2 134 pancam_gibson_left_11_pos_L257R127 Doug, I guess "a little bird" told you about it. Another "preview" (at half-size). What is that strange, two-toned box on the right side of the image? Assuming Spirit retains its Energizer Bunny status, where are they planning on having it explore after Home Plate? -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Guest_Sunspot_* |
Feb 10 2006, 12:59 PM
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#154
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Guests |
I guess if the prelimenary results dont show any evidence for water in the formation of these rocks they wont stop at HP long....
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Feb 10 2006, 02:02 PM
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#155
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Member Group: Members Posts: 153 Joined: 8-February 04 From: Phoenix, AZ USA Member No.: 9 |
QUOTE (tty @ Feb 10 2006, 03:23 AM) It sure does look like a dropstone. Question: have you ever seen such a clear dropstone structure in an eolian deposit? I can only remember seeing them in waterlaid sediments. Wild speculation: Could this be a rhythmite and a "real" dropstone? A lake in Gusev would certainly have had a water regime that varied strongly with the seasons and ice-floes are highly likely too. tty I think that is a great alternative explanation. My first thought on the lower interbedded unit was that it looked like rhythmic/episodic lake beds. With some of the recent ideas about low-latitude glaciation on Mars, it would not be hard to visualize the pre-Homeplate crater as containing ice and a subglacial lake. The closest to an eolian "dropstone" I've ever seen was a large (5-6 cm diam), rounded, polished, quartzite pebble embedded in dune foresets the Jurassic Navajo/Page eolian sandstone in Utah on the Colorado Plateau. However, the likely interpretation of that clast was that it was a dinosaur "gizzard stone" and I'm not sure we want to go there for Gusev.....! -------------------- Tim Demko
BioLink site |
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Feb 10 2006, 02:57 PM
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#156
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Member Group: Members Posts: 531 Joined: 24-August 05 Member No.: 471 |
http://www.space.com/missionlaunches/06021...home_plate.html - Spirit Mars Rover Reaches 'Home Plate': Formation Has Researchers Puzzled
--- For his part, Crumpler said that he refuses to accept one spectacular interpretation: "Namely, that it is a volcanic vent structure." Crumpler said more detailed rover images are needed. Currently these include such possibilities as playa, exhumed crater floor filled with typical Columbia Hills layered deposits, a tuff cone or maar, and a hydrothermal vent area, Crumpler noted. "In fact, it is a healthy debate within the team right now." --- -------------------- - blue_scape / Nico -
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Feb 10 2006, 02:59 PM
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#157
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
QUOTE (SigurRosFan @ Feb 10 2006, 09:57 AM) http://www.space.com/missionlaunches/06021...home_plate.html - Spirit Mars Rover Reaches 'Home Plate': Formation Has Researchers Puzzled --- For his part, Crumpler said that he refuses to accept one spectacular interpretation: "Namely, that it is a volcanic vent structure." Crumpler said more detailed rover images are needed. Currently these include such possibilities as playa, exhumed crater floor filled with typical Columbia Hills layered deposits, a tuff cone or maar, and a hydrothermal vent area, Crumpler noted. "In fact, it is a healthy debate within the team right now." --- Just imagine if steam were seen coming out from under one of the rocks.... -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Feb 10 2006, 03:39 PM
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#158
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Special Cookie Group: Members Posts: 2168 Joined: 6-April 05 From: Sintra | Portugal Member No.: 228 |
QUOTE (Tesheiner @ Feb 10 2006, 12:30 PM) Hey...Is that a shiny perfect spherule right in front of Spirit?... -------------------- "Ride, boldly ride," The shade replied, "If you seek for Eldorado!"
Edgar Alan Poe |
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Feb 10 2006, 03:40 PM
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#159
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Member Group: Members Posts: 311 Joined: 31-August 05 From: Florida & Texas, USA Member No.: 482 |
QUOTE (ljk4-1 @ Feb 10 2006, 08:59 AM) I'd imagine the mossbaur results will help reduce the number of theories, but it's nice to see that everyone's speculation is still in the realm of possibilities. Is the spectrometer requiring more than a 3-day soak time? Does such a long sample introduce noise that confuses the results? |
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Feb 10 2006, 03:43 PM
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#160
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Founder Group: Chairman Posts: 14432 Joined: 8-February 04 Member No.: 1 |
I dont believe it adds noise - but depending on Iron content, a Mossbauer Spectrum could take 3 days - perhaps even longer.
The APXS is still fairly sharp - much longer half-life on its source. Doug |
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Feb 10 2006, 03:46 PM
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#161
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Member Group: Members Posts: 688 Joined: 20-April 05 From: Sweden Member No.: 273 |
QUOTE (tdemko @ Feb 10 2006, 04:02 PM) I think that is a great alternative explanation. My first thought on the lower interbedded unit was that it looked like rhythmic/episodic lake beds. With some of the recent ideas about low-latitude glaciation on Mars, it would not be hard to visualize the pre-Homeplate crater as containing ice and a subglacial lake. The closest to an eolian "dropstone" I've ever seen was a large (5-6 cm diam), rounded, polished, quartzite pebble embedded in dune foresets the Jurassic Navajo/Page eolian sandstone in Utah on the Colorado Plateau. However, the likely interpretation of that clast was that it was a dinosaur "gizzard stone" and I'm not sure we want to go there for Gusev.....! I didn't think of the subglacial angle, but that is a very sensible idea. I've seen subglacial rhythmites in Norwegian caves which looked much like this. I don't quite buy the indurated-sulphates idea. Morphologically this formation practically screams "harder than surrounding rocks", which does not fit with the softness of the Meridiani sulphates. tty |
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Guest_Sunspot_* |
Feb 10 2006, 04:04 PM
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#162
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Guests |
How did this formation become so localised? We havent seen anything else even remotely similar in Gusev - we are seeing totally different rock types appearing at the end of a drive compared to the start - 20/30m. If it is some kind of volcanic related event, wouldn't that cover a huge area?
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Feb 10 2006, 04:18 PM
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#163
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
QUOTE (Sunspot @ Feb 10 2006, 11:04 AM) How did this formation become so localised? We havent seen anything else even remotely similar in Gusev - we are seeing totally different rock types appearing at the end of a drive compared to the start - 20/30m. If it is some kind of volcanic related event, wouldn't that cover a huge area? Probably has been said before, but what the hey: Could Home Plate be a large chunk of rock blown out by either a volcano or meteorite impact from far away? Can we determine from orbital images and spectral data where it might have come from, going on this idea? -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Feb 10 2006, 04:18 PM
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#164
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Member Group: Members Posts: 147 Joined: 30-June 05 From: Bristol, UK Member No.: 423 |
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Feb 10 2006, 05:06 PM
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#165
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Member Group: Members Posts: 531 Joined: 24-August 05 Member No.: 471 |
-------------------- - blue_scape / Nico -
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