Re: Mars ice
Yes, LJ,
That is very much possible. I'm beginning some work on the numbers in such a scenario, basically to show how deep the Deuterium-enriched ice might extend before we hit "primordial" ice with "normal" D/H ratio.
This will show how deep we might need to drill on Mars to answer such questions. From that, we can work out if we can afford to answer the question in that way!