At the end of chapter 4, you have to open the gate to pass the level. On this page of our guide to Darksiders Genesis, you will learn what you have to do to get out of this location and continue the story.
You have to open after defeating one of the bosses - Molten Hound.
After killing the boss, climb the column located on the left side of the arena.
Throw a Void Bomb at the right spot to open the first portal.
Go down and move to the other side. There, open the second portal on the right.
Go back upstairs and throw Bomb Growths into the portal. Quickly go back down to go through the metal gate. This completes the fourth chapter.