Answer;
-Missing layer
An unconformity is a Missing layer of rock.
Explanation;
-Unconformity is a break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long period of time. The missing unit of rock is called an unconformity, defined as a period of either non-deposition or erosion separating two stratigraphic units of rock with different ages.
-There are three types of unconformity which are; disconformity, Nonconformity, Angular unconformity. Disconformity is sequence of parallel rock is missing. It is hard to see but very common. Nonconformity is a sedimentary rock layers lie on top of an eroded surface of a non-layered igneous or metamorphic rock. Layers are on top of non-layered rock. Angular unconformity exists between horizontal rock layers and eroded tilted or folded rock layers. The tilted or folded layers were eroded before horizontal layers formed above them.
