Whatever was going on 3 billion yers ago, whatever the conditions were, it may have little to do with what is going on now. Even this article suggests any rain stopped when the planet "froze." Without that freshening rain over so many aeons, we need to think of other means to produce the deposits we see today.

Mars preserves some surface evidence of of that long ago and apparently longer ago as well, but we really aren't seeing it at a small scale. It's not impossible, but it is highly unlikely that something as fragile as the Pot of Gold formation has endured for billions of years.

The dendric channels which may date to an early period are only obvious in wide angle views from orbit; they are almost imperceptible close up. This indicates substantial erosion on a fairly large scale.

This seems to suggest that most of what we see at a small scale is relatively fresh -- freshly deposited, freshly exposed, or freshly moved from one location to another, though the source material may be quite ancient.

.... pondering....