Figure 7.24: In this photo taken in the Basin and Range province, the photographer is
standing at Emigrant Pass in the Nopah Range, and looking across a basin to the Kingston
Range beyond. ( 1 )
Lesson Summary
- Stress is the force applied to a rock, which may cause deformation. The three main
types of stress go along with the three types of plate boundaries: compression is com-
mon at convergent boundaries, tension at divergent boundaries, and shear at transform
boundaries. - Where rocks deform plastically, they tend to fold. Brittle deformation brings about
fractures and faults. The two main types of faults are dip-slip and strike-slip. - In dip-slip faults, the angle of the fault plane is inclined to the horizontal, in strike-slip
faults the fault plane is perpendicular to the horizontal. - Theworld’slargestmountainsgrowatconvergentplateboundaries, primarilybythrust
faulting and folding.
Review Questions
- Why don’t rocks deform under confining stress?
- What type of stress is compression and at what type of plate boundary is this found?
- What type of stress is tension and at what type of plate boundary is it found?
- What type of stress is shear and at what type of plate boundary is it found?
- What is the difference between plastic and elastic strain?
- A Under what conditions is a rock more likely to deform plastically than to break?
- You are a geologist walking around in the field, when you spot a monocline. You
inspect the fossils in each layer of the rock and you discover that the oldest rocks are