I spoke with Martin Slater, studio director of the former 2K Australia office in Canberra this morning. The fact I said "former" should tip you off that some changes have been made.
The studio once known as 2K Australia, and before that as Irrational Games (Canberra), is now known as... 2K Marin. The 2K studio in Marin, California is also known as 2K Marin. Despite there being 7500 miles of Pacific Ocean between them. Confusing? You're not alone.
The change was made recently for a number of reasons. Firstly, the development teams in Marin and Canberra have been working together for a number of years, first on BioShock 2, now on XCOM (and will continue to do so for future projects), so a decision was made to bind the two together, bring them under the one name (so "2K Australia" no longer exists). That way, 2K felt it wouldn't need to keep differentiating between them, and could just say "2K Marin" and know it covered both.
But why Marin? Why not call it 2K Australia, or come up with something new altogether? Slater says the publisher went with Marin because that name was already an "established brand", thanks to the success of BioShock 2, something 2K Australia - which hadn't led development on a project since 2004's Tribes Vengeance, when it was known as Irrational - lacked.
The partnership means the two studios will be able to run projects concurrently; BioShock 2 was done primarily by Marin, with Canberra's help, while XCOM is being led by Canberra with assistance from Marin.
So, there you have it. We've learned two things from this. One, XCOM is being developed primarily in Australia, and two, 2K really need to stop changing the names of their studios every 18 months, because it's ridiculous we have to make posts like this just to clear things up!