Geology 101: Unit 2

Question 1

fissure eruptions

Answer 1

fluid basalt

Question 2

shield volcanos

Answer 2

numerous fluid basalt flows from a ventral vent

Question 3

cinder cones

Answer 3

basalt -> gas-rich -> explosive eruptions

Question 4

composite volcanoes

Answer 4

andesite & rhyolite composition/lava flows, explosive eruption of ash, stratified or layered.

Question 5

volcanic dome

Answer 5

rhyolite composition, very viscous and erupts slowly → builds high-relief “_____”

Question 6

example: dome

Answer 6

tomichi dome

Question 7

caldera

Answer 7

process begins with a composite volcano, get a huge eruption of ash → empties magma chamber

Question 8

example: caldera

Answer 8

crater lake, oregon

Question 9

nuee ardente

Answer 9

“glowing avalanche” explosive eruptions of composite volcanos

Question 10

example: nuee ardente

Answer 10

St. Pierre (killed ~29,000) enveloped town in 1 minute

Question 11

lahars

Answer 11

a large destructive mudflow on the side of a volcano, composite volcano, not necessarily hot

Question 12

example: lahars

Answer 12

gunnison area → built on “_____” from West Elk Volcano

Question 13

hot springs/ geysers

Answer 13

ground water that seeps down and contacts hot rock

Question 14

example: hot springs/geysers

Answer 14

yellowstone

Question 15

physical weathering (mechanical)

Answer 15

the breakdown of rock into smaller pieces by various physical forces, no change in rock composition —> just smaller rocks

Question 16

chemical weathering

Answer 16

is the chemical breakdown of minerals in a rock by the removal/addition of atoms in the crystal structure of minerals, may produce new minerals

Question 17

rock type

Answer 17

different rock types weather at different rates and by different methods.

Question 18

climate

Answer 18

warm and wet is a much faster rate of weathering.

Question 19

example: shield volcano

Answer 19

mauna loa—> hawaii

Question 20

flat top

Answer 20

are capped with basalt, inverted topography

Question 21

example: flat top

Answer 21

red mountain

Question 22

fissure flows

Answer 22

produce flood basalt/basalt plateaus, erupts from fissures, covers extensive area

Question 23

aa flow

Answer 23

contains little gas, is slow-moving, and is several meters thick, fist size pieces of very sharp basalt

Question 24

pahoehoe lava

Answer 24

ropy lava, more fluid flows, they are thinner, glassy crust forms on top

Question 25

intermediate

Answer 25

andesite

Question 26

mafic

Answer 26

basalt, originates in mantle, very fluid, covers large areas

Question 27

felsic

Answer 27

rhyolite, originates in crust, viscous (gas is trapped in lava), extruded as high relief flows

Question 28

frost wedging

Answer 28

H2O freezes and expands by 9%, night = freezes, day = thaws, waters seeps deep into rocks and then freezes and expands.

Question 29

salt crystal growth

Answer 29

occurs in salt lakes and oceans

Question 30

exfoliation/sheeting

Answer 30

a process in which large flat or curved sheets of rocks fracture and detach from the outcrop

Question 31

chemical weathering

Answer 31

chemical breakdown of rock/minerals at the atomic/molecule level, water is most important here

Question 32

3 major types of chemical weathering

Answer 32

hydrolysis, dissolution, oxidation

Question 33

hydrolysis

Answer 33

a reaction between water and silicate minerals

Question 34

dissolution

Answer 34

minerals dissolve in H2O, slow process

Question 35

example: dissolution

Answer 35

limestone and marble

Question 36

oxidation

Answer 36

rust