From this cross section of the Grand Canyon,what is the boundary between the various Precambrian rocks and the Paleozoic sedimentary units?
A)it is a depositional contact,probably representing only a short period of geologic time
B)it is an angular unconformity in most places and a nonconformity where it overlies granite
C)it generally is an unconformity and represents more time in the right part of the diagram than in the left part of the diagram
D)all of these

Question

From this cross section of the Grand Canyon,what is the boundary between the various Precambrian rocks and the Paleozoic sedimentary units? 
A)it is a depositional contact,probably representing only a short period of geologic time 
B)it is an angular unconformity in most places and a nonconformity where it overlies granite 
C)it generally is an unconformity and represents more time in the right part of the diagram than in the left part of the diagram 
D)all of these

Quizplus · Accepted Answer

The boundary between the Precambrian rocks and the Paleozoic sedimentary units is an angular unconformity in most places and a nonconformity where it overlies the granite. This indicates a significant period of geologic time and erosion between the two rock units.

From This Cross Section of the Grand Canyon,what Is the Boundary