In a sequence of sedimentary rocks,the bottom layer is the youngest and the top layer is the oldest.This type of sequence suggests that the
A)principles of original horizontality and superposition are flawed.
B)beds must have been overturned by some structural disturbance.
C)dates for these rocks must be in error.
D)principles of original horizontality and superposition hold true.

Question

Quizplus · Accepted Answer

In a normal sequence of sedimentary rocks, the principle of superposition states that the oldest layers are at the bottom and the youngest are at the top. If the bottom layer is the youngest and the top layer is the oldest, it suggests that the beds have been overturned by some structural disturbance, such as folding or faulting, reversing their original order.

In a Sequence of Sedimentary Rocks,the Bottom Layer Is the Youngest