Key Points in this Chapter

KEY POINTS IN THIS CHAPTER

• Rocks are under pressure. This pressure can cause rocks to variably bend or fracture.

• Rock types range from being very ductile to being extremely bitter. Temperature and the rate of strain on a rock will determine whether a rock bends or breaks.

• Joints and faults are both cracks in rock. Joints do not move but can expand or contract, depending on the circumstances. Faults are basically joints that have moved with respect to one another.

• Remember the four variations on faults, such as the normal fault and reverse fault, which represent up and down movement. Slip-strike faults slide past one another in two possible ways.

• The dip and slip of rocks will tell you a lot about what has happened to a fracture.

• Folds are from bending rock. There are various patterns of folding inward and outward in symmetrical and asymmetrical ways. Remember that folding features are only really seen when there has been erosion of rock so you can see the layers.

• Mountain building involves fractures and faults or folding and thrusting.

Volcanic mountains do not involve pressure on rock.