Unconformities play a crucial role in reconstructing the geologic history of a location.  They provide a distinct time boundary, separating events that occurred before versus after the unconformity.

Rotate the block below to examine the moderately tilted layers below the unconformity. Then reveal what the unconformity (top face of the tilted, older layers) would look like by removing the horizontal, younger layers above the unconformity.  

Rotate block Reveal unconformity

Unconformities Example