Having ruled out hydrological processes, let us consider volcanoes.

There has been no tectonic activity on Mars for quite some time, if there ever was any tectonic activity on Mars - Mars does not have a large Moon, as the Earth does.

On the other hand, it appears that a sufficiently large impactor can penetrate down to the still fluid parts of a planetary body's core, and a volcano can result, if there is still a fluid core. But the core of Mars cooled long ago, and the spherules are seen near the surface.

But the spherules, in other words the Martian tektites, would not need this high a temperature to form, nor an impact of this magnitude. Any simple hyervelocity impact anywhere on the surface of Mars will interact with the omni-prescent iron dust. (Note that this dust is the result of even earlier impacts of iron asteroid fragments!)

As will be seen from the Viking and Pathfinder images, once NASA has actually processed them to the point at which they are useful, these spherules are then incorporated into whatever rock type is formed in any area. This may be particularly noted in the small circular depressions seen in crater ejecta in any area of Mars, depressions formed when atmospheric erosion loosens the matrix enough for the spherules (tektites) to fall out.

While there is limited water on Mars, as seen by the erosional streams eminating from impact craters, NASA's watery Mars models are like much else at NASA, as they simply do not work.

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