Linux Mint works with x86 and x86-64 CPUs. So you won't be able to use Linux Mint on a SPARC CPU. Ubuntu also no longer supports SPARC; http://www.theregister.co.uk/2010/08/20 ... anic_dead/
I think this is a 64-bit SPARC processor, so according to DistroWatch you have the following options for Linux or BSD distros to consider: http://distrowatch.com/search.php?ostyp ... tus=Active
Debian will work according to that, so that would be nice. You might be able to compile any additional programs you want from LMDE (Linux Mint Debian Edition) from source on that. Gentoo is available as an alternative Linux distro, though that is much more involved, if not complex if you are unfamiliar with it, than Debian.
You could also branch out a bit, and have some fun with one of the BSDs. FreeBSD (biggest BSD distro) or OpenBSD (most secure BSD distro), or NetBSD (with its saying "of course it'll run NetBSD!"m I could have recommended you that blindfolded