I've just posted the location of some strange circular lakes in the random files section. Anybody know what they are?
Wow, good find. I have no idea what they are, but maybe someone else will be able to help out.
The circular depressions are thermokarst lakes formed by melting permafrost. There is a useful account of these at:
Thanks very much! Thought they might have been maars, but they're too widespread. Looks like permafrost does some interesting stuff!
Nice work, GeoDave! I've edited the listing on that file to include this new information.