Geomorphology of Gale Crater, Rock on! |
Geomorphology of Gale Crater, Rock on! |
Sep 26 2012, 10:22 PM
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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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Jan 13 2017, 11:14 PM
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Senior Member Group: Members Posts: 1045 Joined: 17-February 09 Member No.: 4605 |
SAM has the capability to conduct isotopic analysis of the lighter elements. You have a few misconceptions in that sulphate reducing bacteria uses sulphates as an energy source, producing sulphides. Iron pyrite forms in a reducing, not a oxidising environment and on Mars probably formed through melt separation during magma crystallisation.
With respect to your question on what rover and orbital findings indicate about previous environments, these have been the subject of a huge number of erudite papers and articles by acknowledged experts in their fields and address the dramatically different environments encountered by the landers and rovers. A good search engine and some careful culling to separate the grain from the chaff will provide you with your answers and attempting to paraphrase these would take up immense space and justifiably draw the wrath of the overworked moderators. |
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Jan 14 2017, 12:02 AM
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Member Group: Members Posts: 384 Joined: 4-January 07 Member No.: 1555 |
Julius, I agree with what Serpens said, but to try to save you a bit of trouble, let me summarize (with some trepidation) what you are likely to find in an exhaustive literature search. In short, sulfates don't tell you a great deal about environments. Yes, they are oxygen-bearing, but so are virtually all the other minerals that make up planetary crusts, such as silicates and carbonates. Sulfates require a tad more oxygen than most, to avoid forming sulfides instead, but not much more. There are igneous and hydrothermal sulfates as well as sulfides, so sulfates are not unique to a particular environment (at least on Earth). Some elements (e.g., calcium) form sulfates more easily than others (e.g., iron), but you didn't ask about that.
Manganese oxides and hematite on the surface of Mars probably don't tell you a great deal either, because the surface of Mars is believed to be locally far more oxidizing than the inside, owing to the influence of solar ultraviolet light, not from an oxygen-rich atmosphere (as on Earth). It doesn't take a great deal of oxygen to form either type of oxide. Finding manganese or iron oxides inside a rock can tell you that it or its ingredients were formerly exposed to sunlight at the paleo-surface, and presumably to some moisture (to assist their growth), but nothing more. I won't address sulfur isotopes, because there is no data and they are not my area of expertise. |
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