I can’t remember the book

I vaguely recall that a fictional team of archaeologists discovered a Native American city carved into a canyon wall or the side of a mountain. Possibly Navajo? And the military gets involved somewhere else, I believe Yellowstone. They are using the Book of Mormon to find clues for this hidden treasure, and BLAH I think they are racing against time with Yellowstone preparing to pop? I remember reading this book. It was either in High School, or Jail. But I remember an abandoned Navajo city, exploring dried lava chutes a military encampment with a corrupt Colonel, and the Book of Mormon.