Evidence for the presence of an unconformity in the formation below is given by
A)the uptilting of the beds in layer 1.
B)the erosion that must have taken place at the boundary of 1 and 2.
C)the new sediment type deposited at the boundary of 2 and 3.
D)All of these are example of unconformities.

Question

Evidence for the presence of an unconformity in the formation below is given by 
A)the uptilting of the beds in layer 1. 
B)the erosion that must have taken place at the boundary of 1 and 2. 
C)the new sediment type deposited at the boundary of 2 and 3. 
D)All of these are example of unconformities.

Quizplus · Accepted Answer

An unconformity is a time gap in the rock record that occurs when rocks are eroded or not deposited for a period of time. Option B describes the erosion that must have taken place at the boundary between layers 1 and 2, which is evidence of a time gap or unconformity. The uptilting of the beds in layer 1 (option A) and the new sediment type deposited at the boundary of 2 and 3 (option C) do not necessarily indicate an unconformity, but could be due to other geological processes. Option D is not a valid choice because only option B provides evidence for an unconformity.

Evidence for the Presence of an Unconformity in the Formation