The surface below sedimentary rocks that overlie igneous or metamorphic rocks is termed a(n)____________.

A)disconformity
B)angular unconformity
C)nonconformity

Question

The surface below sedimentary rocks that overlie igneous or metamorphic rocks is termed a(n)____________.

A)disconformity 
B)angular unconformity 
C)nonconformity

Quizplus · Accepted Answer

A nonconformity is a type of unconformity (break between two layers of rock) where sedimentary rocks rest on top of igneous or metamorphic rocks. This indicates that there was a period of erosion and uplift that exposed the underlying rocks before the sedimentary rocks were deposited on top. A disconformity occurs between parallel layers of sedimentary rock where there is a gap in the rock record due to erosion, while an angular unconformity occurs where tilted or folded layers of rock are overlain by younger, flat-lying rocks.

The Surface Below Sedimentary Rocks That Overlie Igneous or Metamorphic