igneous rocks-volcanoes

Question 1

what is affected by cooling rate

Answer 1

texture

Question 2

how do large crystal size form?

Answer 2

by slow cooling rates

Question 3

how do small crystals form?

Answer 3

fast cooling rates

Question 4

what does texture include?

Answer 4

crystal size
porosity
if there’s volcanic debris

Question 5

what is extrusive?

Answer 5

at or near surface

Question 6

what is intrusive?

Answer 6

buried deeply

Question 7

what are common igneous textures?

Answer 7

glassy
aphanitic
phaneritic
porphyritic
pyroclastic
vesicular

Question 8

what is glassy?

Answer 8

no crystals

Question 9

what is aphanitic?

Answer 9

small crystals

Question 10

what is phaneritic?

Answer 10

large visible crystals

Question 11

what is porphyritic?

Answer 11

two crystal sizes
two different cooling rates

Question 12

what is pyroclastic?

Answer 12

fragments of rock magma tore off
volcanic

Question 13

what is vesicular?

Answer 13

has holes made from trapped gas

Question 14

what are characteristics of felsic minerals?

Answer 14

light colour
light weight
iron and magnesium poor

Question 15

what are characteristics of mafic minerals?

Answer 15

dark colour
heavy
iron and magnesium rich

Question 16

where are felsic minerals found?

Answer 16

felsic to intermediate rock

Question 17

where are mafic minerals found?

Answer 17

mafic to ultramafic rock

Question 18

what is rhyolite?

Answer 18

felsic
extrusive

Question 19

what is granite?

Answer 19

intrusive
felsic

Question 20

what is andesite?

Answer 20

intermediate
extrusive

Question 21

what is diorite?

Answer 21

intermediate
intrusive

Question 22

what is basalt?

Answer 22

mafic
extrusive

Question 23

what is gabbro?

Answer 23

mafic
intrusive

Question 24

what are xenoliths?

Answer 24

partially melted rock torn off of other rocks

Question 25

how is felsic magma produced?

Answer 25

crystal settling in intermediate magma partial melting of an intermediate rock

Question 26

how is intermediate produced?

Answer 26

crystal settling in mafic rock partial melting of a mafic rock mixing mafic magma with felsic magma assimilating felsic rock into mafic magma

Question 27

what is a volcano?

Answer 27

any landform (could be underwater) that releases lava, gas, ashes, or has done so in the past

Question 28

where do volcanoes occur?

Answer 28

at divergent or convergent boundaries rarely, but sometimes in middle of plate

Question 29

what are the volcanoes that occur in the middle of the plate called?

Answer 29

anomalous volcanoes

Question 30

how does magma chemistry affect the nature of volcanic eruptions?

Answer 30

fewer covalent bonds between tetrahedra= thin runny magma (mafic) more covalent bonds between tetrahedra= thick magma (felsic) thicker magma has high viscosity and more resistance to flow making eruptions more explosive

Question 31

characteristics of mafic lava?

Answer 31

flows easy erupts gently low silica content low gas low viscosity

Question 32

what are the types of mafic lava?

Answer 32

Aa pahoehoe

Question 33

what is Aa lava?

Answer 33

rough fragmented lava blocks sharp rough crumbly

Question 34

what is pahoehoe lava?

Answer 34

smooth shiny and ropey surface

Question 35

what are the characteristics of felsic lava?

Answer 35

erupts catastrophically high silica content high gas content

Question 36

what is pyroclastic debris?

Answer 36

fragments of rock or magma caused by expanding gases anything that gets blown out of a volcano

Question 37

types of pyroclastic debris?

Answer 37

ash lapilli-- little rocks volcanic bombs-- baseball sized rocks volcanic block-- massive rock welded tuff-- little rocks become welded together by ash and water pumice-- low density, lots of pores

Question 38

what are the most abundant gases released from an eruption?

Answer 38

h2o, Co2, and So2 So2 causes acidic rain

Question 39

what are the two main groups of volcanoes?

Answer 39

central vent volcanoes large scale volcanic terrains

Question 40

what are central vent volcanoes?

Answer 40

central vent-- one main release point summit crater

Question 41

what is large scale volcanic terrains?

Answer 41

no central vent network of source material extend over a large area

Question 42

what are the types of central vent volcanoes?

Answer 42

shield cinder cones stratovolcanoes rhyolite caldera complex

Question 43

shield volcanoes have?

Answer 43

shallow slopes mafic magma

Question 44

stratovolcanoes are?

Answer 44

explosive steep sided

Question 45

shield volcanic eruptions?

Answer 45

low silica, low gas, magma originates from the mantle low viscosity creates broad slopes effusive layers caused by repeated volcanic events

Question 46

stratovolcano eruptions?

Answer 46

alternating layers of mafic to intermediate lava flows with layers of intermediate to felsic explosively eject pyroclastic fragments explosive eruptions are common due to build up gases continental settings

Question 47

rhyolite caldera complex eruptions?

Answer 47

high silica, high gas magma massive explosions (most explosions) withdrawal of magma from magma chambers causes collapse produces inverse volcano (think cauldren)

Question 48

what do Large scale volcanic terrains cause?

Answer 48

mid ocean ridges develop at divergent boundaries basaltic flow creates a global network of interconnected seafloor ridges

Question 49

volcanoes at a divergent boundary?

Answer 49

mafic lava flows mid ocean ridge

Question 50

volcanoes at oceanic hot spot?

Answer 50

mafic lava flows shield volcanoes

Question 51

volcanoes at continental hot spot?

Answer 51

felsic to mafic magma flows all types of volcanoes

Question 52

volcanoes at continental oceanic subduction zones?

Answer 52

felsic to mafic lava flows all volcano types volcanoes form a volcanic arc

Question 53

volcanoes at oceanic oceanic subduction zones

Answer 53

intermediate to mafic lava flows shield volcanoes or stratovolcanoes volcanoes form an island arc