These threads might help you out if you haven't seen them already.
http://forum.thegradcafe.com/topic/2954-sub-30-gpas/
You do have a chance, if you make a very good case for yourself, and I think if you do well on the GRE it could help...... But it might really depend on how focused you are. I would recommend figuring out what you would want to specifically study when you go to grad school, rather then applying to a bunch of different program types, and hope you get in somewhere (you might have already done this, I don't know, but it looks like you are looking at a bunch of different subjects). I only mention this because some other people on the forum have said that one of the things profs and addcomms ask is where else you are applying to. If you list off some schools, and they know their own field, and some of the schools you are applying to don't have/ are weak in that field, then they might question how serious you are, and then not take you. It also depends on where you are applying to. There are some very good lower ranked schools that are not as competitive, that would be more willing to give you a shot. It partially depends on if you can get yourself some other good LOR's on top of the one you look like you already have.
PS geology is a hard science, and especially so if you think physics is, because there is a whole field of geophysics. ;-)