Answers in Genesis is a creationist run website but Talk Origins is not. Talk Origins is the real deal! It’s a great source of real scientific facts on the age of the earth and evolution. I took an oceanography paper last year and I remember the lecturer said that the earth’s oceans were millions of years old (cant remember the exact figure) but I think it is somewhere around 500 million years old.
So I guess this is considerabley younger than 4.5 billion years (which is the age of the earth) but that is only because the oceans as we know them today were formed very slowly from water vapor from volcanoes and also water from comets. Also the early earth used to be very hot on the surface and over time this cooled which allowed oceans to be formed.
As for debating creationists, I find that they will quote this or that statistic that the earth isn’t old or that evolution is wrong. By the time you look up the facts it’s too late they have walked away feeling like they won the argument. I find the best way to debate them is to undermine their religious beliefs. Mention Numbers 31:17,
“Now therefore kill every male among the little ones, and kill every woman that hath known man by lying with him. But all the women children, that have not known a man by lying with him, keep alive for yourselves.”
This coming from the all righeous Moses, who is held up as the pinnacle of morality! The same guy who god revealed himself to, and then gave him the 10 commandments. In reality, the guy was a murderer and probably a rapist.