Not even waiting for Los Links to feature this one. My dear friend Ryan Brown, who blogs at Glacial Till, has a fantastic post up, if you love geology, Doctor Who, or both, you must go read it: Geology 101: Deep Time, or Geologists as Time Lords.
To inspire you on your way, I shall now post a photo of the Tenth Doctor looking a bit like a geologist:
Close enough. Give that man a beer.