Dynamic Earth

Front 1

Name the process that keeps the tectonic plates moving on the top of the mantle

Back 1

convection currents

Front 2

Name the region in the mantle where this process occurs

Back 2

asthenosphere

Front 3

Fill in the blanks: Hot magma expands and r____ towards the surface, while the cooler magma near the surface s____. This sets up a continuous circulating flow of m____ which is called a c__________ current

Back 3

rises, sinks, magma, convection

Front 4

Name the 3 types of plate boundaries

Back 4

spreading, collision, transform

Front 5

Identify the type of plate boundary in which:
a) volcanic island chains are formed
b) deep ocean trenches are formed
c) a mid-ocean ridge is formed
d) fold mountains are formed

Back 5

a) collision - oceanic/oceanic
b) collision - oceanic/continental or oceanic/oceanic
c) spreading
d) collision - continental/continental

Front 6

The 4 "spheres" of the earth are the ___________, ___________, __________ and _________

Back 6

lithosphere, hydrosphere, atmosphere and biosphere

Front 7

The lithosphere is made up of the ____ plus the solid upper part of the ____. Below the lithosphere is the part of the mantle called the _____________.

Back 7

rock, earth, asthenosphere

Front 8

The lithosphere is broken up into pieces called tectonic ______ which are slowly moving on top of the mantle due to __________ currents

Back 8

plates, convection

Front 9

When 2 plates are moving apart, it is called a _________ boundary. At these boundaries _____ forces its way through the gap and solidifies to form new ____. The new rock builds on top of itself to form a chain of volcanic mountains called a ___-_____ ridge

Back 9

spreading, magma, rock, mid-ocean

Front 10

When 2 plates are moving towards each other, it is called a _________ boundary. If one plate is oceanic and the other plate is continental, the oceanic plate will _______ underneath the continetal plate. The continental plate will be crumpled ______ at its edge, forming a mountain range. A deep ocean ______ will be formed at the site of subduction. As the oceanic plate moves down into the mantle, it melts and the new magma may rise and erupt in a _______

Back 10

collision, subduct, folded, trench, volcano

Front 11

If both colliding plates are continental, the plates will crumple and fold to form _________

Back 11

mountains

Front 12

The continental drift theory states the continents were once ______ together in a single land mass, called Pangaea, and that they slowly _____ into their current positions

Back 12

joined, moved

Front 13

Evidence for plate tectonics:
a) Matching _______ on widely separated continents, such as the 200 million yr old fern Glossopteris
b) Matching ages and composition of _________ on widely separated continents
c) The ages of the rocks of the ocean floor are _______ than the rocks of the continents, with the youngest rock being next to the mid-ocean ridges and getting older as you work you way outward
d) Magnetic field stripes in the rocks next to the mid ocean ridges

Back 13

fossils, mountains, younger

Front 14

What is the temperature like deep beneath the Earth's surface?

Back 14

thousands of degrees

Front 15

Is the rock in the mantle solid or liquid? Why?

Back 15

Solid because the force is so high, that the pressure keeps the rock solid

Front 16

What is the core made of?

Back 16

iron

Front 17

What is the only truly liquid layer in the Earth?

Back 17

Malten outer layer

Front 18

When a plume of magma rises to the surface of the Earth, the result is a _______

Back 18

volcano

Front 19

The mountain shape of a volcano forms when layers of solidified ____ build on top of one another

Back 19

lava

Front 20

Molten rock, when underground, is called _____

Back 20

magma

Front 21

When brought above ground, the molten is now called ____

Back 21

lava

Front 22

Hot pools and geysers form when a plume of _____ heats up the rocks of the crust without breaking through the crust

Back 22

magma

Front 23

Tidal waves are caused by ___________ under the sea

Back 23

earthquakes

Front 24

All the continents were once joined together into a supercontinent called ______

Back 24

Pangaea

Front 25

The circular movement of magma beneath the Earth is called a __________ _______

Back 25

convection current

Front 26

Spreading ridges are found under the ___. New sea floor is formed as _____ rises to the surface and then _____ to form solid rock

Back 26

sea, magma, tectonic

Front 27

When a land plate meets an oceanic plate, the oceanic plate ______ beneath the continental plate. This is because continental plates are ____ _____ than oceanic plates. This is called a "zone of __________."

Back 27

slides, less dense, subduction

Front 28

Where 2 land plates push together, _________ are formed

Back 28

mountains

Front 29

Australia does not have many earthquakes and volcanoes cos it is in the ______ of a plate and not on the ____

Back 29

middle, edge

Front 30

The split between 2 plates is calld a _____

Back 30

fault

Front 31

The 3 types of fault are:

Back 31

normal fault, reverse fault, strike-slip fault

Front 32

Most earthquakes occur at plate __________. However earthquakes can occur anywhere that ________ builds up

Back 32

boundaries, pressure

Front 33

If pressure is applied slowly to rocks, they will ____ instead of faulting

Back 33

fold

Front 34

What is the name given to the great undersea mountain range and is present in all oceans?

Back 34

Mid-ocean ridge

Front 35

List some of the main features of Mid Ocean Ridges

Back 35

a) rise about 3 000m above the ocean floor
b) are 2 000 - 3 000 km across the base
c) are places where shallow focus earthquakes occur
d) volcanic activitiy takes place, erupting very fluid basalt lava

Front 36

Explain how the process of sea-floor spreading works

Back 36

Basalt magma rises into the fissures in the centre of the MOR, most of it solidifying as dykes

Front 37

What kind of plat boundary is characterised by a Mid-Ocean Ridge?

Back 37

divergent boundary

Front 38

Name and describe other types of plate boundaries

Back 38

spreading: when 2 plates are moving apart
collision: when 2 plates are moving towards each other