Well, I'm not 100% confident, but somewhere around 99.999%...

You've got to understand the processes, the rates, and the evidence that we see or would see if different things are going on. You've also got to understand your own analogue. Simply asserting that it *is* an analogue is insufficient. You have to demonstrate that it is an appropriate one.

Let's look at that...

In Antarctica, meteorites fall onto the surface of the ice, as they do on every square metre of land and ocean.

Those that fall in the ocean fall to the seafloor and either wether away or are entombed in rock. Occasionally, we find rock exposures that contain meteorites. Two striking examples that I am familar with are the worldwide K/T boundary layer that has spherules of meteoritic origin and glass blobs of impact melt; and a Swedish quarry that has numerous meteorite fragments attesting to a meteor storm back in geologic time (memory fails me but perhaps the Eocene?)

Those that fall on land are largely destroyed through weathering and erosion (some are found in peat bogs after a few tens of thousands of years but most are lost in the debris of terrestrial gravel and stones.

In Antarctica, most are lost as the ice slowly creeps from the central domes and cascades over the edge of the continent in icebergs and floes. A few are concentrated in areas of internal drainage where sublimation of the ice locally exceeds snowfall, creating areas where the ice slowly flows inwards and is ablated from the surface down. Any rocky debris is concentrated by thousands to miillions of times in these areas and meteorite finds are common.

OK, that's your analogue. Now how does it apply to Mars?

There is no evidence for glacier-like sideways flow of the rocks in Meridiani. They appear to be now in the place where they were formed. The surface is slowly eroding in the thin dry Martian wind, protected by an armour of residual pellets of haematite and occasional surface rocks that may be meteorites (primary or secondary - recall "Bounce", a possible SNC- type Mars rock that does not belong in the area). The iron meteorite is almost certainly in-situ. When it fell to Mars, it fell here, in this exact spot.

The surface on which it lies may not be the same surface it fell on, though. That surface *is* slowly eroding and the meteorite would settle down with it, as sandblasting plucked away the edges of any slim pillar it might rest upon (so in fact it could have toppled and rolled, or slid or slithered a few metres from its actual original impact site.)

How do we date surfaces on Mars? The only method we have is to extend to Mars the crater-dating methods calibrated on the Moon. Painstaking crater counts reveal a size-frequency distribution for the Moon that can be used to match isotopic ages of maria vs highlands etc. For Mars, we apply a couple of correction factors for closeness to the asteroid belt, and gravity of the target (Mars/Moon). There is some slop here but in principle, surfaces with many large craters are old. Surfaces without even a few small craters are very young.

Areas like Meridiani appear anaomalous in this sort of measurement. They have a moderate number of large craters, suggesting great antiquity (~3.5 billion years), but they also have the crater density for smaller craters appropriate to a younger age, and the smaller you get, the younger the implied age.

This paradox is resolved if you recognise active aeolian erosian - the surface and the small craters are being stripped away about as fast as they form, but huge old craters are too big for the small-scale sand ripples and sand-blasting to destroy. SO we see both ages - the age of original formation, and the age of the current surface. (Recall the ageing of the rover tracks within 6 Earth months - this is the very fine-scale age of the surface!).

Okay, so let's return to your question:-

For example, in the case of this apparent meteorite, it seems to me that the nearest analog on earth to this finding is the meteorites found on the ice surface in Antarctica. While the objects themselves may be of great age, their presence on the Antarctic surface is not particularly ancient. In fact, their presence is quite recent in geologic terms.

Now, could a similar scenario occur on Mars? Could this meteorite have fallen to the Martian surface relatively recently, and if so, might it tell us something about conditions at Meridiani in the relatively recent past?

Well, chemically it's unlikely that an iron meteorite would survive burial in the rock volume that was attacked by concentrated sulphuric acids to form the Meridiani rocks. It must have come later, once the fluids were inactive.

It could have come recently and be almost in-situ, or it could have come some time ago.

To look at the range of time available - consider how many metres of sulphate rock with sparse blueberries you need to destroy to liberate a gravel of blueberries across the entire surface. - I reckon that a hundred metres or more of rock have been destroyed.

Imagine how much time this would take on a dry and almost airless planet? (if it isn't dry and almost airless for the vast majority of time, many other things go wrong, so we can rule that out for almost all of Mars for the past 3-3.5 Ga). The meteorite could have fallen at any time during that interval, and stayed at the surface at the plains around it gradually eroded. (it wouldn't form a pillar like in Anatolia, since the main erosion mechanism is near-surface horizontal sand-blasting, not vertical rain)

We're trading off the probability of earlier fall, vs the accumulation of wear in conditions we don't understand well. But it's likely to have fallen some considerable time in the past, not just recently. (You could do statistics on the likelihood of finding it having searged so many square metres of surface, given the meteor flux at Mars, and hence derive an expected age for it - but that's beyond me at this time of night)

And if it HAD fallen "recently" - the so what? A few tens of thousands of years, or a few million or even tens to hundreds of milli\ons? No real difference in my book - still the dry dead Mars we see today.