Warm-up Week 15 Day 11. It is generally true that igneous rocks are _______.• a. made of silicate minerals. c. easily scratched • b. normally contain fossils. d. contain primarily evaporites.

2. Which factors help determine whether a volcanic eruption will be violent or gentle?

• a. composition of the magma• b. amount of dissolved gases in the magma• c. temperature of the magma• d. composition of magma, temperature, and gas pressure.

3. Most intraplate volcanic activity occurs where ___.• a. hot magma descends into the mantle at a plate boundary• b. oceanic plates diverge• c. oceanic and continental plates converge• d. hot mantle plumes rise toward the surface within a plate

“Orogenesis”“Oro” = mountain

“Genesis” = beginning

Mountain Building!

Chapter 11

Q: How do mountains form?

Plate movements push/pull rocks!

Deformation• Change in shape or size.• Happens at plate boundaries

Forces!Push or Pull

Force & Stress

• Stress = strength of push/pull at one area

• ↑High stress Deformation

3 Types of Stress

1. Tensional– Pulled apart

2. Compressional– Pushed together

3. Shear– Pulled or pushed at

opposite edges

Stress at Faults builds Mountains!

3 Fault Types1. Strike-Slip Fault

2. Normal Fault– Tensional– Fault-block

Mtns.• Horst ↑• Graben ↓

3. Thrust Fault– Compression– Folded Mtns.

Review:• 3 plate boundaries

• ___________ boundaries• ___________ boundaries• ___________ boundaries

• Most mountains at _______________ boundaries.

• 3 Convergent Boundaries• ________ - __________• ________ - __________• _________- __________

Convergent

Divergent

Transverse

Convergent

Oceanic Oceanic

Oceanic Continental

Continental Continental

Volcanoes!

Folded Mtns!