Eiga Doraemon: Nobita no nankyoku kachikochi daibouken

Unable to endure the midsummer heat, Doraemon transports Nobita and his friends to a huge iceberg floating in the South Pacific. While creating an amusement parks with the secret tool "Ice-working Iron" the group finds a mysterious golden ring in the ice. Upon closer examination, they determine that the ring was buried in Antarctica 100,000 years ago - before people could have lived there. (imdb)