How about trying out some specifically Martian explanations for what is becoming an almost iconically Martian topography and environment in Meridiani?

By "specifically Martian" I mean an almost always very cold surface, at near-vacuum atmospheric pressures. Let's not assume that there was ever a "clement" period on Mars, except perhaps locally in some areas (probably not in Meridiani) due to impact or eruption.

Let's go farther and assume that water in a pure state is and has always been rare on Mars -- whether liquid or ice it doesn't much matter, because quantities have always been and are now relatively small, but certainly not absent.

However, active fluids have been and probably still are found at and near the surface -- such as sulfuric acid, for example, that must have been present when the Meridiani formations originated.

While we keep hearing that the "rock" -- if you want to call it that -- found in Meridiani (it's a layered deposit, filled with hematite spheres, at any rate) must have formed in water, is that true, or is that a convenient shorthand while precipitates and formations in acids are explored?

What we see is an apparently eroded layered deposit, some of which appears almost fluid even now, sand, dust, and countless hematite spheres, half-spheres, quarter-spheres and their smaller fragments.

Is there anything on Earth -- or any other planet -- that compares with what is seen in Meridiani? Or is this a very unique environment, unique to Mars, but very widespread on Mars?

There are indubitably depressions or basins in parts of Meridiani -- but I seem to recall that most of Meridiani is highland terrain, not part of the Northern Lowland, so it doesn't make much sense to try to link it in any way to the putative (sulfuric acid?) ocean that may or may not have been present in the Northern Lowlands in times gone by. Yet some areas of Meridiani are apparently at the "0" elevation we find near or at the margins of the Northern Lowland. Could there then have been a connection? Parts of Meridiani may have been sites of lakes of some sort, perhaps ice-covered or subsurface. Indeed, why couldn't lakes still exist subsurface?

How do the Meridiani deposits relate to the numerous layered deposits found in craters all over the planet -- well away from Meridiani? Do the dark deposits we see apparently spilling out of craters to the north and west of Meridiani relate to the vast deposits of hematite spheres apparently pervasive in Meridiani? And if these spheres are hematite and spread over a vast area, why are orbital readings of hematite concentrated in very small areas of Meridiani and some other regions? Or is this apparently pervasive hematite deposit actually confined to a relatively small area?

On and on. But you get the idea...

Cheers, BRFelix