Mountain formation
Bell ringer (write the question) What are the three kinds of faults? What type of stress is responsible for the creation of a strike slip fault? What type of plate boundary do you find at a reverse fault? What fault do you find at a divergent plate boundary?
Faulted What are the three kinds of faults? Unit 2 Lesson 5 Mountain Building Faulted What are the three kinds of faults? Sometimes rock is under so much stress that it breaks. A crack called a fault forms when large blocks of rock break and move past each other. The three main kinds of faults are strike-slip faults, normal faults, and reverse faults. Copyright © Houghton Mifflin Harcourt Publishing Company 3
What are the three kinds of faults? Unit 2 Lesson 5 Mountain Building What are the three kinds of faults? In a strike-slip fault, the fault blocks move past each other horizontally. Strike-slip faults form when rock is under shear stress, or stress that results from the sliding of rock structures in parallel but opposite directions. Copyright © Houghton Mifflin Harcourt Publishing Company 4
What are the three kinds of faults? Unit 2 Lesson 5 Mountain Building What are the three kinds of faults? In a normal fault, the hanging wall moves down relative to the footwall. Normal faults form when rock is under tension, which is stress that stretches or pulls rock apart. Copyright © Houghton Mifflin Harcourt Publishing Company 5
What are the three kinds of faults? Unit 2 Lesson 5 Mountain Building What are the three kinds of faults? In a reverse fault, the hanging wall moves up relative to the footwall. Reverse faults form when rocks undergo compression, which is stress that squeezes or pushes rock together. Copyright © Houghton Mifflin Harcourt Publishing Company 6
What are the three kinds of faults? Unit 2 Lesson 5 Mountain Building What are the three kinds of faults? Which kind of fault is shown in each image? Copyright © Houghton Mifflin Harcourt Publishing Company 7
Moving on Up What are the three kinds of mountains? Unit 2 Lesson 5 Mountain Building Moving on Up What are the three kinds of mountains? Mountains can form through folding, volcanism, and faulting. The process by which land rises or mountains form is called uplift. Because tectonic plates are always in motion, some mountains are constantly uplifting. Copyright © Houghton Mifflin Harcourt Publishing Company 8
Most folded mountains form at convergent boundaries. Folded mountains form when rock layers are squeezed together and pushed upward. Most folded mountains form at convergent boundaries. Copyright © Houghton Mifflin Harcourt Publishing Company 9
Volcanic mountains Volcanic mountains form when melted rock erupts onto Earth’s surface. Most volcanic mountains form at convergent boundaries. Copyright © Houghton Mifflin Harcourt Publishing Company 10
Unit 2 Lesson 5 Mountain Building Fault Block mountains Fault-block mountains form when tension makes the lithosphere break into many normal faults. Pieces of the lithosphere sink, and the blocks left standing are the mountains. Copyright © Houghton Mifflin Harcourt Publishing Company 11