Chaos in Zion

Chaos in Zion is a main quest

Detailed walkthrough
This quest begins when the Courier kills any storyline-essential character or is caught stealing from or openly kills friendly tribals. They are then required to travel to White Bird's Cave to retrieve the Zion Canyon map and are then instructed to travel back to the Southern Passage, through which they can return to the Mojave Wasteland.

Bugs
During Crush the White Legs, Joshua Graham will already be next to Salt-Upon-Wounds after he leaves to find another route. He will then die before the player can reach Salt-Upon-Wounds making it impossible to save him, activating Chaos in Zion.