The Dark Dunes Of Erebus |
The Dark Dunes Of Erebus |
Oct 11 2005, 09:28 PM
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#1
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Member Group: Members Posts: 713 Joined: 30-March 05 Member No.: 223 |
I've always been fascinated by the dark dune fields of Mars, resembling
in color the sands of, for example, the "black beaches" of Hawai (inidcating the volcanic/basaltic origin ...) Here is a colorized view of The dark Dunes of Erebus, as seen by Opporty on Sol 608 (click on image for full resolution (900 KB)) |
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Oct 11 2005, 09:50 PM
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#2
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Junior Member Group: Members Posts: 83 Joined: 19-April 05 Member No.: 251 |
Oil sands
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Oct 11 2005, 10:52 PM
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#3
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Junior Member Group: Members Posts: 45 Joined: 25-March 05 Member No.: 216 |
lol - if we did discover oil on Mars - expect a 1000x increase in funding...
QUOTE (ddeerrff @ Oct 11 2005, 02:50 PM)
-------------------- My Open Office Website: http://www.openofficetips.com
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Oct 12 2005, 01:17 AM
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#4
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Senior Member Group: Members Posts: 2997 Joined: 30-October 04 Member No.: 105 |
Wonderful image, Nirgal.
I'm looking forward to examining the so-called "Elephant Dune" on the left side of the image. Those dunes are a redder color than the basalt-hematite sands of the ripples and I've seen a couple of instances where light-colored piece of evaporite is high in the dune. I'd suspect these are related to the ejecta blanket of Erebus. --Bill -------------------- |
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Oct 12 2005, 05:15 AM
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#5
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Member Group: Members Posts: 178 Joined: 13-September 05 Member No.: 498 |
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Oct 12 2005, 05:25 AM
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#6
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
These dunes/drifts/ripples really are beautiful, and Nirgal's colorized snapshot was quite evocative. Now that we are seeing them 'in person,' it is much easier to interpret the orbital images.
The white patch on top of the large drift has caught my attention, too. I would like to imagine it is the tip of a taller outcrop surrounded by recent sediments. But we really haven't seen prior evidence of outcrops that tall. I am still trying to convince myself that evidence of the ancient ejecta blanket exists, and has not been eroded off. Some parts of the surface look a bit jumbled, while other outcrops display bedding that is mostly contiguous between the blocks. This is fun. And then there are those circular features that have become common. We need to map them. -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Oct 12 2005, 06:51 AM
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#7
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Senior Member Group: Members Posts: 2997 Joined: 30-October 04 Member No.: 105 |
I've seen no remnants of an ejecta blanket, either. Erebus is an ancient and highly eroded crater and we're seeing the bottom of the crater bowl. Although we see tilted strata in places, for the most part it is meridiani-flat. There are many little pieces of a puzzle that are starting to come together.
Glad to see you back, CR. --Bill -------------------- |
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Oct 12 2005, 10:05 AM
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#8
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Senior Member Group: Moderator Posts: 4279 Joined: 19-April 05 From: .br at .es Member No.: 253 |
QUOTE (CosmicRocker @ Oct 12 2005, 07:25 AM) These dunes/drifts/ripples really are beautiful, and Nirgal's colorized snapshot was quite evocative. Now that we are seeing them 'in person,' it is much easier to interpret the orbital images. The white patch on top of the large drift has caught my attention, too. I would like to imagine it is the tip of a taller outcrop surrounded by recent sediments. But we really haven't seen prior evidence of outcrops that tall. I am still trying to convince myself that evidence of the ancient ejecta blanket exists, and has not been eroded off. Some parts of the surface look a bit jumbled, while other outcrops display bedding that is mostly contiguous between the blocks. This is fun. And then there are those circular features that have become common. We need to map them. Isn't that white patch actually an outcrop on Erebus west side seen behind the dune/ripple? |
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Oct 12 2005, 02:46 PM
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#9
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Senior Member Group: Members Posts: 2997 Joined: 30-October 04 Member No.: 105 |
We'll see better when we get closer, but I do believe that the white patch is on the crest of the dune. Here is a 5x exaggeration of the most recent Pancam image: the white patch is on the third dune back and looks to me to be in front of the Erebus rim outcrop.
There is another "white patch" on a ripple to the south that Oppy imaged a few Sols ago. Let me go through my archives tonight and I'll post another image. --Bill PS-- the earlier image is 1P180568717EFF60UPP2379L2M1. Evaporite boulder on the ripple crest at the crater edge. -------------------- |
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Oct 13 2005, 12:50 PM
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#10
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Senior Member Group: Moderator Posts: 4279 Joined: 19-April 05 From: .br at .es Member No.: 253 |
I think you are right.
I checked it again, both left and right eye images, and there is no apparent difference in parallax between the dune and the white feature i.e. they are at the same distance. |
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Oct 18 2005, 08:16 AM
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#11
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Senior Member Group: Moderator Posts: 4279 Joined: 19-April 05 From: .br at .es Member No.: 253 |
That white patch can be clearly seen on sol 616 images.
http://nasa.exploratorium.edu/mars/opportu...OUP2399L2M1.JPG |
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Oct 18 2005, 12:55 PM
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#12
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Senior Member Group: Members Posts: 2997 Joined: 30-October 04 Member No.: 105 |
Yes, this entire area we are approaching is interesting. Not only are we encountering the largest dunes yet, they also have pieces of the evaporite rock high up in the dunes, and the Four Lane, where it meets the dune, appears to contain in-place ledges of a dark-colored rock. (EDIT: well, a rubble-pile of darker rock that is different than what we've seen)
This is the Four Lane two Pancam frames to the right of the image you presented, and I've added a 5x-vertical exaggeration view. I hope Oppy spends some time looking around here. --Bill -------------------- |
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Oct 18 2005, 09:28 PM
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#13
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Member Group: Members Posts: 866 Joined: 15-March 05 From: Santa Cruz, CA Member No.: 196 |
QUOTE (Tesheiner @ Oct 18 2005, 08:16 AM) That white patch can be clearly seen on sol 616 images. http://nasa.exploratorium.edu/mars/opportu...OUP2399L2M1.JPG I think its most likely to be the eroded bedrock dust (not any sort of outcrop) that collects at the top of this area due to the terrain features of the dune that make it probably in this area (itsa as if theres a little bowl or saddle feature up on that dune conjunction). Remember, at eagle crater there similarly was this white dust collected in the ripples of the little dinner plate sized crater at the foot of the lander offramp. which is apparently a rare occurrence, otherwise the white dust just blows away and we get cleaned dunes, but you can also see a lesser amount of dust in that earlier image of this similarly saddle-shaped area on the foreground dune http://mitglied.lycos.de/user73289/misc/oppy_p18216a.jpg |
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Oct 22 2005, 01:34 PM
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#14
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Senior Member Group: Members Posts: 2997 Joined: 30-October 04 Member No.: 105 |
To add to my post of 18 Oct, here is a color image of the "rubble-pile of darker rock that is different" with a vertical exaggeration of 5x. It was taken on or about Sol 617-618.
A closer look at the rubble pile left me underwhelmed, and Oppy is back to dune-surfing. D: --Bill -------------------- |
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Mar 8 2006, 09:42 PM
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#15
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
-------------------- "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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