An interesting question.
I think the huge features you mentioned were formed independently of each other, at differing times and all under catastrophic conditions.
Perhaps a clue to these past catastrophes on Mars are the irregular shaped close-orbiting moons Deimos and Phobos.
It could be that these moons were once blasted into space along with huge amounts of debris.
If this is so, then perhaps their points of origin were in the Valles Marineris disaster.
Some of this debris completely escaped from Mars and much rained back down onto the planet.
The "moons" were recaptured into an orbital configuration along with other orbiting debris.
Another clue to past catastrophes, is that the ice-caps themselves are offset to the polar axes, suggesting perhaps the occurrence an axial tilt of the planet during some of these upheavals.
If this is correct, then the ice-caps have not yet had sufficient time to reassemble around the true geographical poles.
This could be indicative of a recent upheaval.
Other features offer signs of recentness too, such as the fresh-looking canyon floors of Valles Marineris and of course the rock-strewn landscapes.
To me, a lot of those rocks do not appear sufficiently eroded to have remained there for millions of years.
With the frequent localised and global dust storms etc in evidence, surely most of these rocks should be completely buried by now and any that we do see ought to be rounded-off in their contours.
In addition to your question concerning the formation of the Valles Marineris, the Hellas basin and the Tharsis bulge, perhaps an even greater mystery exists in respect of the dichotomous hemisphere's, but no doubt that would be the subject of another thread.
So, in respect of the Hellas/Tharsis/Mariner features you mentioned, I would settle for their formations to have been independent of each other and recent.
Depends on one's viewpoint.
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|Re: Shattered planet||267||Diomede||04-Feb-04 19:28|
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|Re: Shattered planet||241||Geoff||05-Feb-04 03:15|
|Re: Shattered planet||246||Mercury Rapids||05-Feb-04 09:51|
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|Re: Shattered planet||426||Brew99||10-Feb-04 05:05|