That's a very nice article you pointed to there.

What it brings to mind, over my morning coffee, is a question as to possible relationships between phase states and ph.

But the strata desciption in the article is confusing, as at one time (not identified) you have a high salt solultion, at another time a high acid solution (date for this last given as ca "2 billion years ago" which as always has to be taken as a very rough number.) Where is the layer showig the sequestration of the minerals in the salt solution, or their interaction with the new sulfur sources? What happened to them?

Assume an impact which places a large amount of iron into the atmosphere (blueberries). Some of the iron interacts with the sulfuric acid, or was there a release of sulfur? Was the sulfur volcanic? I don't think so, as I know of no craters deep enough to reach Mar's magma, as some impacts have been on Earth (El Gygantin?) What was the source for the sulfur? Troilites?

What I'm trying to consider here is the following question: We know the volatiles on Mars outgassed. How was this outgassing affected by impact?
There are mechanical processes (simple acceleratin) thermal processes (a general heating by impact energy, with vapor high in the atmosphere) and finally chemical - on the Earth at KT, you have carbon sequestration through combustion, with carbon release and carbon dioxide formed only as life forms re-emerged. On Mars it would have been different each time, depending on the intial state.

end of rumination