Chapter 13 Section 1Volcanoes 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. a vent or fissure in Earth’s surface through which magma and gases are expelled
b. any activity that includes the movement of magma toward or onto Earth’s surface
c. magma that flows onto Earth’s surface; the rock that forms when lava cools an solidifies
d. 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.
The End !!!