CHPTR 3/4 Igneous Rocks

Question 1

magma

Answer 1

molten rock beneath the surface of the Earth

Question 2

parts of magma

Answer 2

molten rock, crystals, dissolved water, gas

Question 3

what negative ion is lava made of

Answer 3

SiO4^4- (silicate ion)

Question 4

lava

Answer 4

magma once it reaches the surface

Question 5

plutonic

Answer 5

intrusive - cools slowly underground - larger crystals

Question 6

volcanic

Answer 6

extrusive - cools quickly at the surface - smaller crystal grains

Question 7

felsic lava

Answer 7

high silica, lower melting point, high viscosity

Question 8

mafic lava

Answer 8

low silica, higher melting point, low viscosity

Question 9

interlocking grains

Answer 9

similar to a camo pattern - evidence that the rock crystallized from liquid state

Question 10

pyroclastic texture

Answer 10

rock formed from particles that travelled from volcano through the air. when they land on the ground they weld together

Question 11

glassy

Answer 11

cooling is so fast that there is no time for crystals to form

Question 12

vesicular

Answer 12

voids formed by bubbles of volatiles that expanded close to the surface and could not escape from the lava/magma

Question 13

amygdaloidal

Answer 13

vesicles that have been filled in with secondary minerals long after the flow cooled

Question 14

frothy

Answer 14

vesicular rock and very light - more air than rock

Question 15

phaneritic texture

Answer 15

slow cooling, crystals visible - like camo pattern

Question 16

porphyritc

Answer 16

mixed rate of cooling. starts cooling then phenocrysts form. cooling is then faster and remaining melt forms groundmass - big rock in small rock

Question 17

groundmass

Answer 17

the small crystals in porphyritic rocks

Question 18

phenocrysts

Answer 18

large crystals within a porphyritic rock

Question 19

aphanitic

Answer 19

fast cooling produces fine grained rock and crystals not visible - “looks like a rock”

Question 20

pegmatitic

Answer 20

large grains formed in water rich magma. crystals larger than 1cm

Question 21

felsic rock intrusive and extrusive rock pairs

Answer 21

intrusive: granite - extrusive: rhyolite

Question 22

intermediate rock intrusive and extrusive rock pairs

Answer 22

intrusive: diorite - extrusive: andesite

Question 23

mafic rock intrusive and extrusive rock pairs

Answer 23

intrusive: gabbro - extrusive: basalt

Question 24

ultramafic rock intrusive and extrusive rock pairs

Answer 24

intrusive: peridotite - extrusive: komatiite

Question 25

tabular

Answer 25

flat body

Question 26

massif

Answer 26

not flat - shapeless

Question 27

concordant

Answer 27

parallel to sedimentary layers

Question 28

discordant

Answer 28

cut across existing rock layers

Question 29

dykes

Answer 29

tabular, discordant pluton

Question 30

sills

Answer 30

tabular, concordant plutons

Question 31

laccoliths

Answer 31

dyke extends upwards and forms a little rock mound to bulge upwards

Question 32

batholiths

Answer 32

massif, area >100km - evidence of past subduction zones

Question 33

stocks

Answer 33

smaller than batholiths igneous extrusion

Question 34

dike swarms

Answer 34

set of parallel dikes at the same age

Question 35

mantle plume

Answer 35

adds heat to an area - determines which volcanoes in Hawaii are active

Question 36

what happens to boiling point as you decrease temp

Answer 36

it also decreases

Question 37

how can lowering pressure melt rocks

Answer 37

at a mid ocean ridge, the plates seperate this causes the mantle to flow upwards into the low pressure area

Question 38

in ocean volcanoes, is the lava felsic or mafic

Answer 38

mafic

Question 39

how can changing composition melt rocks

Answer 39

ocean crust subducts, bringing water into the mantle of the continental plate, this lowers the melting point and ultramafic melt forms

Question 40

volcanic ash

Answer 40

pyroclastic material <2mm

Question 41

lapilli

Answer 41

pyroclastic material 2-64mm

Question 42

bombs/blocks

Answer 42

pyroclastic material >64mm

Question 43

pyroclastic flow

Answer 43

a fast-moving, high-density current of hot volcanic rocks and gas that flows down the side of a volcano

Question 44

lahar

Answer 44

volcanic mud flow or debris - can occur without an eruption

Question 45

Volcano Explosivity Index

Answer 45

used to measure the size of an eruption - measured by the volume of material ejected and the height of eruption column

Question 46

shield volcano

Answer 46

formed by mafic lava. caldera forms as the summit collapses. very wide and gentle slopes

Question 47

caldera

Answer 47

lake at top of volcano caused by its summit collapsing into itself

Question 48

cinder/scoria cone

Answer 48

formed by one eruptive eps. monogenetic

Question 49

monogenetic

Answer 49

a volcano that only erupts once in its life

Question 50

strato-volcano/composite volcano

Answer 50

alternating layers of ash and lave, steeper slopes - generally andesite - rhyolite

Question 51

approximate angle of a composite volcanoe

Answer 51

45 degrees

Question 52

volcanic dome

Answer 52

A lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano after the initial explosion which results in a crater

Question 53

what does a symmetrical volcano imply

Answer 53

it is young and active

Question 54

what kind of lava is in fissure eruptions

Answer 54

mafic (low viscosity) - basaltic lava flow

Question 55

volcanic pipes

Answer 55

the hard part of the the conduit after the on of the volcano is weathered away

Question 56

what kind of tectonic boundary has the least number of volcanoes

Answer 56

transform

Question 57

what kind of heat transfer does the lithosphere experience

Answer 57

conduction

Question 58

what kind of heat transfer does the mantle experience

Answer 58

convection

Question 59

what kind of heat transfer does the outer core experience

Answer 59

convection

Question 60

what kind of heat transfer does the inner core experience

Answer 60

conduction

Question 61

volcanic assimilation

Answer 61

rocks surrounding magma chamber (host rocks) break off and mix with magma

Question 62

magma mixing

Answer 62

two chambers of magma connect and mix

Question 63

magmatic differentiation

Answer 63

crystallization and settling - different temp. causes crystals to form - crystals sink to the bottom - remaining liquid is more felsic

Question 64

Bowen's reaction series definition and order of series. + why is Plagioclase feldspar unique

Answer 64

order of crystallization with a change in temperature Highest temp/Crystallizes first - olivine - pyroxene - amphibole - biotite - potassium feldspar, muscovite, quartz Lowest temp/Crystallizes last Plagioclase has continuous series of crystallizations

Question 65

pluton

Answer 65

a large body of igneous rock that forms when magma solidifies underground

Question 66

why is felsic lava explosive and mafic is not

Answer 66

in mafic lava, gas can escape in felsic lava, the gas cannot escape

Question 67

pahoehoe

Answer 67

higher temperature mafic lava (1100-1200 C)

Question 68

aa

Answer 68

lower temperature mafic lava (1000-1100 C)

Question 69

underwater mafic lava

Answer 69

pillow lava

Question 70

what is dominant gas extruded during volcanic eruption + what percentage

Answer 70

8% water vapour

Question 71

Volcano emissions of carbon dioxide ____ times less than the human contribution

Answer 71

100

Question 72

Most recent super volcano

Answer 72

Toba on Sumatra in Indonesia 74 000 years ago

Question 73

What is most likely next supervolcano

Answer 73

Yellowstone

Question 74

what kind of plate boundary forms the most volcanoes

Answer 74

convergent plate boundaries - specifically subduction zones

Question 75

What formed the Andes

Answer 75

Ocean - continent subduction zone

Question 76

What formed the Appalachians

Answer 76

continent- continent convergent boundary

Question 77

what formed the Himilayas

Answer 77

continent-continent convergent boundary

Question 78

What formed the Alps

Answer 78

continent-continent convergent boundary