check your gravity map.

Or improve your gravity map so that you can take a detailed look, if you need to.

And where are your detailed IR images of the area? And where are your super-resolution IR images of the area?

You can tell the feature is young by the sole large crater on the northern plume.

Now if you had decent crater counts, which you don't, you might be able to at least provide some date brackets, but you can't, because you haven't done the crater counts.

One thing that can be said, on the basis of this one crater, is that the feature is no longer active.

Notice the holes in the plumes caused by subsurface collapse. This gives you some idea of the frozen volatile content of this particular area.

Note that here the feature did not cause a chain reaction release of volatiles, as the release of volatiles by impacts in other regions sometimes has.

Always check the larger context before attempting an analysis of any local feature. You haven't provided that context. Given that this feature is on the floor of a deep trench, which was most likely caused by the release of volatiles, perhaps there is good reason to expect low volatile content.

But then you have no date, not even a reasonably approximate one, for the formation of the trench, now do you?

ah yes, "seondary impact craters" and "plate tectonics' and "volcanism" on Mars- right up there with "Nemesis" as non-starters - along with 1% comet impact rates at 100 million year intervals - why not spend some money doing crater counts on the old Soviet Venus radar data, so you can at least do some decent dating? After all, good data can prevent a lot of useless speculation.

Since you've put Nick on the spot on this, I hope you did not mind me doing the same to you. oh well - only a few more weeks until the Mars water data finally starts to come in