It’s no secret that family trips to Yellowstone National Park are likely to involve arguments in the back seat, but you may not know that (adult) scientists find plenty to argue about there, as well.

Yellowstone is actually just the present manifestation of a family of volcanic events going back almost 20 million years. The textbook explanation for this is that Yellowstone sits atop an example of a “mantle hot spot”—a deep plume of hot rock that rises to the surface of a tectonic plate, periodically punching a line of eruptions as the plate moves. But some scientists have proposed more complex scenarios in recent years.

For example, a study we covered just a few months ago concluded that a region of hotter, shallow mantle pulled in from beneath the Pacific by the tectonic collision with North America could explain Yellowstone and other volcanic features in Western North America.