Instead of the expected sedimentary deposits, Perseverance encountered igneous rock. These rocks can form when magma cools underground or when volcanic material solidifies at the surface. Because the minerals inside igneous rocks can preserve information about the conditions present when they formed, they can provide exceptionally detailed geological records.

In the Margin Unit, those rocks revealed an unexpectedly complicated history. The evidence indicates that they interacted with water on at least three separate occasions, and each episode changed their chemistry and physical appearance in different ways. The findings were published in the journal Communications Earth & Environment.