Final answer:
An unconformity is a pattern in a group of rocks that indicates erosion has occurred. There are four types of unconformities, each with its own characteristics and geologic significance.
Step-by-step explanation:
Simply speaking, an unconformity is a pattern that you look for in a group of rocks that tells you erosion has taken place. Rocks exposed on the Earth's surface are affected by physical and chemical weathering processes that work to break them into smaller pieces or dissolve them in water. This material is then transported away by wind, water, or ice, a process known as erosion. Many unconformities can be found in sedimentary rocks, indicating that sediment deposition was not continuous.
There are four types of unconformities: disconformity, nonconformity, paraconformity, and angular unconformity. Each type forms in a slightly different way and tells a unique story of the geologic history of the area.