PLATE TECTONICS

Question 1

who came up with the continental drift theory

Answer 1

Alfred wegener

Question 2

what’s the name of the one land mass?

Answer 2

panagea

Question 3

what is the name of the 2 land masses once it split?

Answer 3

laurasia and gondawanaland

Question 4

what evidence is there to prove plate tectonics?

Answer 4

fit of continents
fossils
climate and ice
palaeomagentism and sea floor spreading

Question 5

what is palaeomagentism?

Answer 5

magnetic field of igneous rock containing minerals(eg. iron) which aligned at time of cooling.
EG. symmetrical pattern either side of mid atlantic ridge

Question 6

structure of the earth

Answer 6

inner core
outer core mantle
upper mantle (aethenosphere and lithosphere)
crust

Question 7

what is moho discontinuity?

Answer 7

change in composition between thin outer skin of crustal rock and upper mantle.

Question 8

what are the 4 plate boundaries?

Answer 8

constructive(divergent)
destructive(convergent)
conservative(transform)
collision

Question 9

what is a constructive/divergent plate boundary?

Answer 9

2 plates move apart
gentle volcanic activity and minor earthquakes
new islands form as crust emerges

Question 10

what is a destructive/convergent plate boundary?

Answer 10

subduction zone
2 plates move towards each other
-trenches,earthquakes,violent volcanos
oceanic under continental

Question 11

what is a conservative/transform plate boundary?

Answer 11

2 plates sliding past each other
earthquakes
crust not lost or made

Question 12

what is a collision plate boundary?

Answer 12

continental plate colliding
fold mountains
violent earthquakes
crust not lost or made

Question 13

characteristics of a oceanic plate

Answer 13

8km thick
3.2g/cm^3
iron and magnesium

Question 14

characteristics of a continental plate

Answer 14

30-70km thick
2.7g/cm^3
silicone and aluminium

Question 15

how to plates move?

Answer 15

convection currents

Question 16

what is orogenesis?

Answer 16

process of mountain building

Question 17

what is orogeny?

Answer 17

period of time mountains take to form

Question 18

what is the basic process of orogenesis?

Answer 18

compression
folding
uplift

Question 19

what are fold mountains?

Answer 19

folding of rock in strata in the upper part of the crust

sedimentary rock

Question 20

what is a volcanic island arcs form?

Answer 20

volcanoes in a arc shape

generally due to subduction of oceanic plate

Question 21

how do oceanic trenches form?

Answer 21

long narrow depressions in sea floor
deepest part of ocean
moves from few mm to over 10cm
occurs at a subduction zone

Question 22

case study : how do the Himalayas form?

Answer 22

60 million years ago - indian and Asian plate collide
push against each other
crust squeezed upwards
40 million years ago- heavy sediment sinks under Asian plate. closing up the Tethys sea

20 million years ago- Tethys sea gone. sediment pushed up to from Himalayas. Tibet begins to rise

today - indian plate continues to rise due to squeezing

predictions for 10 million years from now
Nepal no longer exists. mountains continue to form advancing edge of india.

Question 23

what is a volcano?

Answer 23

a volcano is a vent in the earth’s crust geographical landform where magma erupts through the surface.

Question 24

what are the 3types of lava?

Answer 24

basaltic, andesitic and rhyolitic

Question 25

what are the properties of andesitic lava?

Answer 25

``` high silica content less frequent 800c viscous violent ash,steam,lava,tephra ```

Question 26

what are properties of basaltic lava?

Answer 26

``` frequent gentle low viscosity 1200c lava and steam low silica content ```

Question 27

what are the 6 types of volcanos

Answer 27

``` fissure shield ash/cinder caldera strato/composite acid/dome ```

Question 28

what is a fissure volcano?

Answer 28

basaltic lava effusive eruptions spreads wide and far

Question 29

what is a shield volcano?

Answer 29

builds up from previous eruptions basaltic lava slightly domed

Question 30

what is a ash or cinder volcano?

Answer 30

mainly ash and tephra 30m to 400m high pyroclastic material

Question 31

what is a caldera?

Answer 31

circular depression huge eruption collapse of magma chamber

Question 32

what is a strato or composite volcano?

Answer 32

basaltic and andesitic lava layers in rock tall/concial mountain

Question 33

what is an acid/dome?

Answer 33

steep sided convex cone andesistic lava

Question 34

2 examples of igneous rock

Answer 34

granite and basalt

Question 35

properties of basalt

Answer 35

extrusive small crystals- short time to cool dense constructive plate boundary

Question 36

properties of granite

Answer 36

``` large crystals long time to cool less dense destructive plate boundaries long time to cool in aesthenosphere ```

Question 37

what is a lava plateau?

Answer 37

intrusive and extrusive flat/wide surface lava spreads quickly

Question 38

what are the 2 types of plutons?

Answer 38

batholith and laccoliths

Question 39

what is a batholith?

Answer 39

under earths surface molten rock injected into crust | 1 to 100 cubic km

Question 40

what is a laccolith ?

Answer 40

close to earths surface causing rock to bend intrusive

Question 41

what is a dyke?

Answer 41

discordant cuts across layers of bedding crystalised or fine grains

Question 42

what is a sill?

Answer 42

concordant sheetlike injection into current bedding rock 1 to 100 metres thick

Question 43

what is an extinct volcano ?

Answer 43

extrusive no lava supply no longer near an active hotspot

Question 44

``` case study : mount etna location plate boundary type of volcano impacts ```

Answer 44

location: east coast sicily Italy. 100km south of messina and 30km north of Catania plate boundary: subduction of African under Eurasian. destructive plate boundary type of volcano: stratovolcano on top of shield volcano 3323m high, explosive eruptions. acid lava 2002-2003 impacts social: 1000 leave their homes 100 homes damages schools shut 2002-2003 impacts environmental: crops damaged pine forest damaged 2002-2003 impacts economic: tourist resorts affected damage to business crops =livelihood