Here's why:
* Disconformity: This type of unconformity occurs between parallel layers of sedimentary rock. The layers are often similar in composition, and the boundary between them may be subtle, especially if erosion has removed much of the evidence of the missing time.
* Other Unconformities:
* Angular Unconformity: This unconformity involves tilted or folded sedimentary layers being overlain by younger horizontal layers. The sharp angle between the layers is quite obvious.
* Nonconformity: This unconformity occurs between igneous or metamorphic rock and overlying sedimentary rock. The difference in texture and composition between the two types of rock is usually very noticeable.
In summary, disconformities are harder to spot because the difference in the layers might be subtle, while angular unconformities and nonconformities have more obvious visual cues.
