It may be a matter of semantics, but the the Argentina charge is not a "Visa." It's a reciprocity fee --whatever is charged to Argentinians when they arrive in the U.S. It's increased since I was there a couple of years ago. Too bad you can't get in on arrival anymore, it was quick and easy. I hope all travelers know they need to get it online now.
Have a great trip. Antarctica should be a wonderful experience.