Is there a certificate in australia i can do via correspondence/online in order to gain entry in to university?

ok so im 22,I only have a cert for year 10 .I now wish to become a geologist.I'll be starting work in mackay soon so studying on a campus isn't an option.Ideally id like to save 60k and finish the necessary study over the next 18 mths which is not the problem.ive been looking for online study or via correspondence since ill be working 12hr a day 6 days a week ,but ,so far i cant find any such thing .I havent got anyone to talk to about this and am stuck. any help from someone who has done something like this before or someone who has half a clue would really be helping me a great deal.............ideally ill study chem,bio,phys,english and two maths subjects maybe a couple more, depending.