Geomorphology of Gale Crater, Rock on! |
Geomorphology of Gale Crater, Rock on! |
Sep 26 2012, 10:22 PM
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#31
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Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
I'd like a discussion thread about the geology detatched from the time limits of current MSL threads. We had a 'Geomorphology of Cape York' thread that attracted a lot of interesting posts. How about 'Geomorphology of Gale Crater'? I have one or two ideas but many more questions, and I'd like to post them in a longer-running thread away from the day to day imaging discussion. Any other takers?
For starters, does anybody have a contour map of this place like the one at Meridiani with 5m intervals? ADMIN: You have your wishes fulfilled on UMSF (sometimes) |
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Oct 6 2012, 09:30 AM
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#32
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Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
I am particularly intrigued by the enclosed depression on the right of Peter's contoured elevation map:
http://petergrindrod.net/wp-content/upload...g-site-topo.png The depression coincides exactly with the outer margin of the high thermal inertia fan (HTIF). I'm also curious about where the substantial quantity of flowing water that formed the fan was actually flowing to. I'm toying with the idea that it spread out and froze in place, forming over time a substantial ice deposit. I don't know the proper name for such a thing so for now I'm calling it an 'ice snout'. Maybe all of the HTIF is a marker for the former extent of the ice snout. Sublimation of volatiles is widely invoked to explain hollows. Here we appear to have a hollow and a ready supply of volatile material at some time in the past. There are what look like polygonal markings on the bottom of the depression. Where have we seen that before? I can't wait to get down there. |
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Oct 6 2012, 07:26 PM
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#33
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Junior Member Group: Members Posts: 85 Joined: 5-September 12 Member No.: 6635 |
I am particularly intrigued by the enclosed depression on the right of Peter's contoured elevation map: http://petergrindrod.net/wp-content/upload...g-site-topo.png Sublimation of volatiles is widely invoked to explain hollows. Hmm - The peculiarity of the craterlet density in the unit covering the area SE of Glenelg has been mentioned earlier in this thread. Notice the complete saturation and fairly uniform size of these little hollows in the eastern part of this unit. Could this unit be a remnant of a sediment saturated outflow that was deposited more or less all at once ?? Assuming the slurry is near the triple point pressure of H20, small variations in conditions within the slurry could result in explosive boiling one place while a few meters away the slurry is still liquid. At the same time it is rapidly freezing on its surface so that the little craterlets that are left behind as the vapor bubble breaks the surface are flash frozen in place. IF the slurry is thick enough the craterlets might still be discernible as the remaining H20 slowly sublimates away and the remaining dry deposit settles. (this is somewhat consistent with your "ice snout" idea) |
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