What type of geologic contact separates the rocks of the Canadian Shield from the rocks of the Great Plains? (Hint: Consider the type and age of the rocks found in each area.)
A)intrusive contact
B)strike-slip fault
C)thrust fault
D)unconformity

Question

Quizplus · Accepted Answer

The correct answer is D) unconformity. The Canadian Shield is composed of some of the world's oldest rocks, which are primarily igneous and metamorphic, while the Great Plains are covered by much younger sedimentary rocks. An unconformity represents a significant gap in the geologic record, often where older rocks have been eroded away before being overlain by younger rocks, which is the case between the ancient rocks of the Canadian Shield and the relatively younger sedimentary rocks of the Great Plains.

What Type of Geologic Contact Separates the Rocks of the Canadian