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.

For the block below, an unconformity exists between the tilted layers of the bottom section and the horizontal layers of the top section.  On your worksheet (U-1), sketch what the block would look like if the unconformity were to be revealed (the top layers removed).

Rotate block

Unconformities Example