Chapter 6 Quiz

At which points on this graph is the magma under the highest amount of pressure and highest temperature?

1

For the volcanic eruption in this photograph, complete the two missing parts of the sentence using the type of volcanic feature and type of magma. "This figure shows a ________(type of volcanic feature) that forms from _______________________, ___________ (type of magma)."

1. lava flow 2. eruption of low-viscosity 3. mafic lava

For the volcanic eruption in this photograph, complete the three missing parts of the sentence using the viscosity, composition, and resulting rock type. " This figure shows an eruption of ________(viscosity) magma that probably has a ________________(composition) and would form _________(resulting rock type)."

1. low - viscosity 2. mafic 3. scoria

Which of the numbered features is a pyroclastic flow?

4

How could a rock at point C be melted?

All of these choices are correct.

Some scientists think that Yellowstone could cause a future disaster because

All of these choices are correct.

Which of the following is likely to be true about the right volcanic feature compared to the left one in this figure?

All of these choices are correct.

At which of the sites shown in this figure would melting probably be caused by introduction of water into hot rocks?

C

Examine this figure and correctly complete this sentence using the proper phrase. "Changing conditions from points _____ would result in decompression melting."

C to B

The largest concentration of composite volcanoes on Earth is located along the

Pacific Ring of Fire.

Which of the following are ways that viscosity affects gases in magma?

Viscous magma prevents gas from escaping easily.

What type of volcanic eruption is probably shown in this photograph?

basaltic lava flow

Continental mantle plumes that are composed of felsic magma tend to be explosive when the Earth's surface is reached. These explosive eruptions create

calderas.

The igneous rocks shown in this photograph are forming

columnar joints.

The most dangerous type of volcano is a

composite volcano.

Which of the following plate boundaries is least likely to produce composite volcanoes?

continent-continent convergent boundary with a high mountain range (Himalayas)

The igneous feature shown in this figure is a

dike

Cinder cones are composed primarily of

ejected fragments of vesicular lava.

Shield volcanoes commonly involve

fluid lava flows.

When basaltic lava reach the ocean they

form pillow basalts.

Volcanic mudflows (lahars) are common on composite volcanoes because

large amounts of rain and snowmelt mix with loose ash on steep slopes.

What tectonic setting is interpreted to be the cause of volcanism at Yellowstone?

movement of North America over a mantle plume

Rocks of the continental crust contain different minerals and each mineral has its own melting point. If the minerals with the lowest melting temperatures are the only ones melted, this is referred to as

partial melting.

Which of the following materials is NOT produced by erupting volcanoes?

sandstone

Volcanic domes commonly are partially destroyed when

steep parts of the dome collapse and cause small pyroclastic flows.

Shield volcanoes have low slopes primarily because

the low viscosity of basaltic magma allows it to flow downhill for long distances.

What generally happens when subduction-derived magma encounters thick continental crust?

the magma interacts with the crust, forming felsic or intermediate compositions

What type of basaltic feature is shown in this photograph?

volcanic bomb

Columnar joints, like the ones shown in the photograph, are formed

when hot but solid igneous rock contracts.

For the volcanic eruption in this photograph, complete the three missing parts of the sentence using the viscosity, composition, and resulting rock type. "This figure shows an eruption of ____________(viscosity) magma that probably has a __________ (composition) and would form __________(resulting rock type)

1. high-viscosity 2. felsic or intermediate 3. rhyolite or andesite

Which of the following sites would most likely have composite volcanoes? A is on an island arc, B is in the Andes, C is near Hawaii, D is along a mid-ocean ridge.

A and B

When a volcano erodes and the solidified conduit is exposed, it is referred to as a volcanic

neck