Chapter 9: Volcanoes and Igneous Activity

Question 1

Factors that determine the violence of an eruption.

Answer 1

1) composition of magma
2) temperature of magma
3) dissolved gases in magma

Question 2

Viscosity

Answer 2

is a measure of a material’s resistance to flow

EX: the flow of honey when cold and heated up.

Question 3

The factors affecting the viscosity of magma

Answer 3

1) temperature
2) composition
3) dissolved gases

Question 4

two components to the composition of viscosity

Answer 4

high silica - high viscosity

low silica- low viscosity

Question 5

The process which lava flows

Answer 5

moves through the asthenosphere and then through the continental crust to the surface aka the lithosphere

Question 6

Basaltic lava

Answer 6

mafic lavas that are more fluid thank felsic lavas

Question 7

Types of lava

Answer 7

Pahoehoe lava (resembles braids in rope)
Aa Lava (rough, jagged blocks)

Question 8

Volcanic gases

Answer 8

gases make up 1-5% of magma by weight

mainly water vapor and carbon dioxide

Question 9

Examples of Pyroclastic Materials

Answer 9

Scoria
Pumice
Volcanic ash, volcanic bombs, lapilli, and volcanic blocks

Question 10

Volcanoes general features

Answer 10

Volcanic pipe
vent
lava tube
crater 
caldera

Question 11

volcanic pipe

Answer 11

carries gas-rich magma to the surface

Question 12

vent

Answer 12

the surface opening (connected to the magma chamber via a pipe)

Question 13

lava tube

Answer 13

tunnel in a hardened lava that acts as a conduit for molten lava to flow from vent

Question 14

Crater

Answer 14

steep-wall depression at the summit

Question 15

Caldera

Answer 15

a summit depression greater than 1 km diameter

Question 16

What is the difference between a crater and caldera?

Answer 16

A crater is a steep walled depression at the summit of the volcano
A caldera is a depression greater than 1 km in diameter

Question 17

Different types of volcanoes

Answer 17

Shield volcano
Cinder cone
Composite

Question 18

Shield Volcano

Answer 18

Slightly dome shaped 
Primarily made of balsamic (fluid) lava
Generally the largest volcano 
Most begin as seamounts on the bottom                            
     of the ocean floor 
Resembles a broad shield in profile

Question 19

Cinder Cone Volcano

Answer 19

Volcanoes built from ejected lava fragments
Has a steep slope angle
Small in size, compared to shield or composite
Frequently occur in groups

Question 20

Composite Volcano

Answer 20

Adjacent to Pacific Ocean aka “Ring of Fire”
Large, but not the biggest
produces the most violent activity

Question 21

Nudee Ardente

Answer 21

“burning cloud”
fiery pyroclastic flow made of hot glasses infused with ash
Can produce lahar

Question 22

Basalt

Answer 22

dark, fine-grained, igneous rock; makes up the majority of the ocean floor

Question 23

Volcanic necks

Answer 23

are the resistant vents left standing after erosion has removed the volcanic cone

Question 24

An underground igneous body is called what?

Answer 24

pluton

Question 25

Types of intrusive Igneous Features

Answer 25

Dike - tubular pluton that moves at an angle
Sill- tubular pluton that is horizontal
(buried lava flow)
Laccolith - lens shaped (blister) magma mass
Batholith - largest intrusive body of all plutons
(forms the cores of mountains)

Question 26

Examples of Igneous rocks

Answer 26

Granite
Pumice
Basalt

Question 27

Examples of Sedimentary rocks

Answer 27

Sandstone
Brecca
Limestone

Question 28

Examples of Metamorphic rocks

Answer 28

Gnesis
Marble
Schist