Comanche |
Comanche |
Dec 24 2005, 06:01 AM
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#76
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
I noticed them, too. I think Bill is correct. We've occasionally seen these things in previous MIs and even other cameras. My best guess is that these are specular reflections from shiny surfaces, quite possibly from some tiny crystal faces of the minerals comprising the rock.
If I had noticed such glints while inspecting a rock on earth with my hand-lens, I'd focus in on the spots to see if I could recognize the mineral. -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Dec 24 2005, 07:27 PM
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#77
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Senior Member Group: Members Posts: 1229 Joined: 24-December 05 From: The blue one in between the yellow and red ones. Member No.: 618 |
QUOTE I noticed them, too. I think Bill is correct. We've occasionally seen these things in previous MIs and even other cameras. My best guess is that these are specular reflections from shiny surfaces, quite possibly from some tiny crystal faces of the minerals comprising the rock. Would you see such "sparklies" in earth-bound basalts? Or are we seeing some kind of appended salt crystal? Shame we can't 'rat' this sucker and get some fresh views. It could be a real Christmas decoration! I hope they TES it anyway, before we head for the "abyss" -------------------- My Grandpa goes to Mars every day and all I get are these lousy T-shirts!
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Dec 25 2005, 07:11 AM
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#78
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
If the light is right, you might expect to see specular reflections from almost any clean rock surface, since most are composed of the cemented grains of individual mineral crystals. I'd be surprized if this was a basalt, though.
It could be a salt crystal, but it could really be most any kind of crystal. There's no telling, and no way to know what it is with the instruments available on the rover. All we can know is that it is a flat, reflective surface that sent a ray of sunlight into lens of the camera. -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Dec 25 2005, 08:13 AM
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#79
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Senior Member Group: Members Posts: 2998 Joined: 30-October 04 Member No.: 105 |
I doubt that the "crystal" is a salt. When I said "salt deposit" I meant more of an efflorescence, which I frequently see where mineralized phreatic water evaporating through a porous sandstone. I doubt that is happening here, but this was my first impression.
I've seen these strong mineral grain reflections many times, and this is puzzling to me since my mental image of Martian rocks is dusty and abraded and there _shouldn't _ be fresh surfaces. Nonetheless, they show up occasionally and I need to remove my blinders... Once we know what the rock is we'll be able to make shrewd guesses as to what the crystal likely is. --Bill -------------------- |
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Dec 25 2005, 11:08 AM
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#80
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Member Group: Members Posts: 362 Joined: 12-June 05 From: Kiama, Australia Member No.: 409 |
QUOTE (Bill Harris @ Dec 25 2005, 07:13 PM) I doubt that the "crystal" is a salt. . I've seen these strong mineral grain reflections many times, and this is puzzling to me since my mental image of Martian rocks is dusty and abraded and there _shouldn't _ be fresh surfaces. Could be sapphires or rubies?, on Earth they are usually associated with basalts of some type. Unlikely but possible. More likely if not salts, to be rutile or ilmenite as some of the rocks are high in titanium and these are hard, weathering resistant minerals already identified in previous analysis I think?? |
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Dec 25 2005, 05:08 PM
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#81
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Senior Member Group: Moderator Posts: 3431 Joined: 11-August 04 From: USA Member No.: 98 |
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Jan 1 2006, 05:23 PM
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#82
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Solar System Cartographer Group: Members Posts: 10184 Joined: 5-April 05 From: Canada Member No.: 227 |
I'm returning to this thread to add a few polar projections from the approach to Comanche. They are all derived from the always excellent panoramas of jvandriel. I especially like the large area of bright bedrock on sol 693.
This first one is sol 692, downhill from Miami. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Jan 1 2006, 05:26 PM
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#83
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Solar System Cartographer Group: Members Posts: 10184 Joined: 5-April 05 From: Canada Member No.: 227 |
Here's sol 693. I really look forward to seeing detailed stratigraphic mapping of this area from stereo images. Hard to believe there's so much exposed bedrock.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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