Geomorphology of Gale Crater, Rock on! |
Geomorphology of Gale Crater, Rock on! |
Sep 26 2012, 10:22 PM
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#201
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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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Jun 18 2019, 07:45 PM
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#202
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Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
Let me take a step back-
I've been thinking about some great ideas from earlier parts of this discussion-
At some point if the debris breaks down into sufficiently small particles it can be removed from the vicinity, even lifted out of Gale crater completely. So it might not remain in this area to choke off further erosion.
An internal heat source beneath Gale can do more than locally hardening the sediments once formed. It could be the reason they formed in the first place. Imagine a largely frozen Mars with plenty of water in the form of ice or ice-capped seas. Now in Gale Crater picture a geothermally heated lake that is at least sometimes ice-free. The liquid surface acts as an effective dust trap 'quickly' filling the whole thing with horizontal sediments. This avoids the need to bury and exhume a similar pile of sediments on a planet-wide scale.
One thing I would want to check is the direction of the tilt and how that relates to the long-term changes in Mars' shape due to, say, the construction of the Tharsis volcanic complex. The MESSENGER team has shown how lava-filled craters near Mercury's pole now have tilted floors that must once have been horizontal, due to tectonic activity. My own work on Venus dealt with the same thing, measuring current topography of lava surfaces that you assume started out as flat in order to get at ancient tectonics. I'm sure the same could happen on Mars. We certainly know Mars' shape has changed in the past, and it's been suggested that the entire crust has reoriented (true polar wander). I'd love to see if the tilting observed here is consistent with geophysical work on Mars' tectonics -- or inconsistent, which would be just as interesting. They're all interesting because they've all recently gotten some support, A- A regional Martian groundwater level, which could supply sufficient water to a crater hydrothermal system to dissolve basalt breccia into sufficiently small particles to blow away, or perhaps flow way as muddy ground water. B- If Gale crater had 1,800 cubic KM of impact melt in a magma chamber, we'd expect it to stay warm and wet for a long time, such that the lake, any peak ring, and the central mound, would all initially have fumaroles and brines and hydrated minerals to trap dust to create Mount Sharp. As the site cooled and a crater lake formed, expect more dust to accumulate. C- Earlier modeling of boxwork features around -3600 elevation might make more sense if we consider a possible -3707 level for a Northern "Arabian Ocean" once the Olympus Mons bulge is removed. Alternate idea, work backwards to figure out the the volume of water moving through the 500 km long watershed, into Farah Vallis and into Gale. |
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