Volcanoes and Plate Tectonics Chapter 13 Section 1 Volcanoes and Plate Tectonics

1 The cause of many volcanic eruptions is the movement of Earth’s tectonic plates.

2 Combined temperature and pressure in the lower part of Earth’s mantle keeps rocks below their melting point.

3 Despite high temperature, most of the mantle remains solid because of the large of amount of pressure from the surrounding rock.

4 Which of the following is NOT a way magma can form? Addition of fluids, such as water, increase the melting point of some minerals in the rock

5 Magma rises upward through the crust because The magma is less dense than the surrounding rock.

6 Lava flows from an opening in Earth’s surface called a vent.

Matching 7. volcanism 8. lava 9. batholiths . volcano a vent or fissure in Earth’s surface through which magma and gases are expelled any activity that includes the movement of magma toward or onto Earth’s surface magma that flows onto Earth’s surface; the rock that forms when lava cools an solidifies large plutons that cover an area of at least 100km2 when exposed on Earth’s surface

10 A major zone of active volcanoes encircling the pacific ocean is called the Pacific Ring of Fire.

11 On the ocean floor, along the edge of the continent where the plate is subducted, a deep trench forms.

12 When oceanic lithosphere subducts beneath oceanic lithosphere, magma rises to the surface to form an island arc.

13 Explain what happens as magma comes to the surface where plates move apart at mid- ocean ridges. As plates pull apart, magma flows upward adding materials to the mid-ocean ridge and creating new lithosphere. The magma erupts to form underwater volcanoes.

14 What is happening in Iceland, where volcanic eruptions happen along mid-ocean ridges? Iceland is divided by the North American plate and the Eurasian plate. Half of Iceland is moving East and the other half is moving West. Magma flows to Earth’s surface through large fissures in the middle of Iceland.

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