Why was Superman so weak when he confronted Lex Luthor and his henchmen on the new landmass?
To make the new landmass an unwelcoming place for Superman, Lex encased the Kryptonian crystal in a cylinder of Kryptonite, knowing that it would take on the characteristics of the Kryptonite as it grew. Located under the crystalline surface, the Kryptonite weakened Superman, causing him much pain and making him vulnerable to attack. Prolonged exposure would likely have killed him.
