Liquid water? What liquid? There is some liquid present, but it's not really the defining characteristic. And yes, it's water.
Deep-sea volcanic vents? No
*yawns* *some applause* An apt description (of both game and answer)

[Irouléguy] I'm usually pretty hopeless at these geographical minerally ones so I leave them to more worthy participants, which I guess doesn't help much. Trouble is, if these posers are not guessed within 3 days, the game tends to lose its momentum. It is now Day 8 of this one so perhaps a chairman's summary of the positives might help? Then a clue?

Chalky] Fair points all, though I have been trying to steer people away from the more detailed minerally answers (and I was away for most of three days). It's really not obscure - I feel sure that everyone will have heard of it.

Summary - it's terrestial, partly solid, sort of an object. (Those are the answers which I think have caused people to go astray, but it's problematic because of what exactly "it" is. Let's say that "the answer" is defined by solid objects.
There's a strong connection to the earth's crust (which is just the top bit of the earth itself -between 5 and 65km thick), and specific geographical features have got strong applause. It's NOT - man-made, either of the Poles, Antarctica, a tectonic plate, an oilfield, a continental shelf, a volcano, the Canadian archipelago, the Greenland icecap (or any other form of ice).
Clues 1) It's very aptly named; 2) it has a university named after it; 3) over four million people went there last year.

Iceland? No
Is it specifically in either the north or southern hemisphere? Yes, the northern.