ESC Earth Science Ch6 Q

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

1

Which of the numbered features is a pyroclastic flow?

4

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

Some scientists think that Yellowstone could cause a future disaster because

All are correct. (the area is part of a caldera. scientists think that magma is still present at depth. past eruptions from Yellowstone carried ash over a huge area of western North America. land near Yellowstone is uplifting in some places and subsiding in others.)

How could a rock at point C be melted?

All of the above: - increase in temperature - decrease in pressure - increase in temperature accompanied by a decrease in pressure

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 are correct. (The magma has a lower viscosity. The magma has fewer silicate chains. The magma probably formed at a higher temperature.)

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

C

Changing conditions from points ____________ would result in decompression melting.

C to B

This figure shows an eruption of ____________ (viscosity) magma that probably has a ____________ (composition) and would form ____________ (resulting rock type).

Low-vicosity; mafic; scoria

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

Movement of North America over a mantle plume

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

Pacific Ring of Fire

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

Pahoehoe lava flow

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

Sandstone

These photographs show different types of eruptions. Drag the name of the eruption type to the correct photograph.

Top left : Lava flow Top right : Lava fountain. Bottom left : Lava dome. Bottom right : Eruption Column

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

Viscous magma prevents gas from escaping easily.

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)

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.

This figure shows a ____________ (type of volcanic feature) that forms from ____________ (type of magma).

lava flow; eruption of low-viscosity, mafic lava

This figure shows an eruption of ____________ (viscosity) magma that probably has a ____________ (composition) and would form ____________ (resulting rock type).

low; mafic; scoria WRONG!!!!!

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

neck

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.

The igneous feature shown in this figure is a

sill WRONG!!!! (maybe dike?)

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 expands.