Geology 3263
Structural Geology
Homework Ch 10 – Folds
This homework is for the lecture marked “Chapter 10 Folds” in topic
folder 10.
1. In ductile processes, deformation is retained.
a. True
b. False
2. A deformation is plastic if permanent strain increases at
same stress.
a. True
b. False
3. Folds are more common in
a. convergent margins
b. divergent margins
4. An anticline is a fold that is convex in the direction of
a. the youngest beds
b. The oldest beds
5. A syncline is a fold that is convex in the direction of
a. the youngest beds
b. The oldest beds
6. We apply the terms antiform and synform to any fold in
which facing direction and/or stratigraphic order is
a. unknown or uncertain.
b. known
7. A hinge line joins line of maximum curvature along the
same layer
a. True
b. False
8. Overturned folds have a limb that has rotated beyond
vertical.
a. True
b. False
9. We usually describe folds as seen by looking down the
fold axis or down plunge.
a. True
b. False
10. If the hinge is sharp, that point is called the
a. hinge point
b. hinge zone.
11. The axial surface of a fold connects all the hinge points
in all successive layers.
a. True
b. False
12. Axial surfaces are
a. always planes
b. may be cruved surfaces
13. We measure the axial surface with its dip direction and
the angle of dip
a. True
b. False
14. The Strike of an axial surface can always be
determined by remembering that strike is
a. perpendicular to dip
b. parallel to dip
15. The profile plane is used to describe the true shape of
a fold. It is viewed
a. parallel to the hinge line
b. Perpendicular to the hinge line
16. In cylindrical folds, the hinge line is
a. straight
b. curved
17. In a layer of sediment with graded bedding, the
uppermost layer has
a. the coarsest particles
b. the finest particles
18. Parasitic folds give us information about sense of shear
on the fold limbs as well as the location of larger-scale
fold hinges.
a. True
b. False
19. The assymetry of S, M, and Z folds will give a sense of
rotation and position of the fold when viewed down
plunge.
a. True
b. False