dougettinger wrote:My survey of the forum has revealed very little support for an impactor on Mars causing the Valles Marineris except for Von Daniken; however, Mars is the site of some of the largest impact basins in the solar system and also has the largest mountain volcano. The Wikepedia reason for this largest of canyons is that the Tharsis plateau swelled and thereby caused the crust in the area of Valles Marineris to collapse. From my personal inspection and the analysis of the experts this canyon was not caused by a direct impactor, by massive flooding, by the shrinkage of the crust due to a cooling planet, or by a subduction zone between two tectonic plates. Also, another large canyon, Ma'adim Valles, is present on the high plateau regions of Mars. Does anyone disagree with the idea of the swelling of the plateau and collapse of the crust ? For most forum personnel Valles Marineris is so mysterious that they hide their heads in the sand like flamingos.
Now, I posit the next question. What caused the Tharsis plateau to swell ? What caused the huge volcanism on Mars after its differentiation of crustal materials was completed ? The answer is very important to uncovering a huge mystery here on Earth.
Interestingly, when you look at the Mars MOLA map
the Hellas impact basin sits at 45deg S Latitude and between 60 & 90deg Longitude.
Olympus Mons sits at 45deg N Latitude and 240deg Longitude.
This places the volcano almost exactly opposite the impact basin and is a possible cause for the existance of the solar system's largest volcano.
Much of the elevated region of the Tharsis Plateau could be a result of volcanism and lava flow from both Olympus Mons and
the other three major Tharsis volcanos Arsia Mons, Pavonis Mons, and Ascraeus Mons.
Another possibility is the debris from the Hellas Impact could have traveled around the globe of mars and settled there.
Or a possible combination whereby the Hellas debris settled on the far side from the impact and then was covered by resulting volcanism.