Video Transcript
Which structural element of a fold divides it in two? (A) The fold crest, (B) the fold axis, (C) the fold hinge, (D) the fold limb, (E) the
axial plane.
A fold is a wavelike structure formed by the bending of any type of rock due to
compressional stress. The highest point of the fold surface is the fold crest. The fold axis is an imaginary line found in the middle of a fold that joins together
the points of maximum curvature on a folded surface. The fold axis may also be referred to as the fold hinge.
The axial plane is an imaginary plane that bisects a fold into two-halves that are as
similar as possible. The sides of a fold are called the limbs. They extend out from the fold’s axis and are found on either side of the axial
plane.
The question asks which structural element of a fold divides it in two. We can see from the diagram that the element that bisects a fold into two-halves is
the axial plane.
