Answer: unconformity
Step-by-step explanation:
An unconformity is a gap in a rock record that has been caused by weathering or erosion. The name refers to the way they don´t adhere to usual geological expectations.
An exemplary sequence of rocks would have all the strata stack up. If they don´t, the gap between the mismatched strata is an unconformity.
The different kinds of unconformity are angular conformity, disconformity, and nonconformity.