Science 10 Chapter 12

Front 1

Continental drift theory

Back 1

Continents have not always been in their current locations but have drifted here over millions of years

Front 2

What details support the continental drift theory?

Back 2

1. Geological structures match from continents

2. fossils are found of the same species in different continents

3. All continents used to have glaciers

Front 3

Paleoglaciation

Back 3

The extent of ancient glaciers and the rock markings they leave behind

Front 4

Tectonic plates

Back 4

The surface of Earth is broken into large, movable slabs of rocks called tectonic plates

Front 5

Volcanoes

Back 5

openings in Earth's surface that when active spew out gases, chunks of rocks, and melted rocks

Front 6

Earthquake

Back 6

A sudden ground shaking release of built up energy at or under Earth's surface

Front 7

Mid-Atlantic Ridge

Back 7

A long mountain range running down the middle of the Atlantic Ocean

Front 8

Magnetic Reversal

Back 8

The process in which Earth's magnetic field reverses its direction

Front 9

Paleomagnetism

Back 9

The study of the magnetic properties of ancient rocks.

Front 10

Magma

Back 10

Molten rocks from beneath Earth's surface

Front 11

Why does magma rise?

Back 11

It is less dense than materials around it

Front 12

What happens when magma breaks through Earth's surface?

Back 12

Magma cools and hardens at a spreading ridge

Front 13

Spreading ridge

Back 13

The region where magma breaks through Earth's surface, forming new sea floor

Front 14

Sea floor spreading

Back 14

The process in which magma rises to Earth's surface at spreading ridges and pushes older rocks aside

Front 15

Plate tectonic theory

Back 15

The movement of tectonic plates

Front 16

Hot spot

Back 16

An area where molten rock rises to Earth's surface

Front 17

Lithosphere

Back 17

The crust and upper portion of the upper mantle

Front 18

Crust

Back 18

Earths outer most layer made up of light materials

Front 19

Mantle

Back 19

Earth's thickest layer

Front 20

Outer core

Back 20

A liquid layer under the mantle

Front 21

Inner core

Back 21

Earth's centre

Front 22

Asthenosphere

Back 22

Molten layer of the upper mantle

Front 23

Ridge push

Back 23

When magma cools when it reaches the surface, solidifies, and is pushed aside as new magma pushes from below

Front 24

Rift valley

Back 24

When currents of magma rises on land and forms a steep sided valley

Front 25

Subduction

Back 25

The action of one tectonic plate pushing underneath another

Front 26

Slab pull

Back 26

When the denser oceanic plate subducts under the lighter continental plate, and the rest of the plates follow

Front 27

Plate boundary

Back 27

An area where two plates are in contact

Front 28

Divergent plate boundaries

Back 28

Areas where plates are spreading apart

Front 29

Convergent plate boundaries

Back 29

Areas where plates meet

Front 30

Transform plate boundaries

Back 30

Areas where plates move past each other

Front 31

Trench

Back 31

A deep underwater valley that forms when an oceanic plate collides with a continental plate and is forced to slide beneath it

Front 32

volcanic belt

Back 32

A long chain of volcanoes

Front 33

Volcanic arc

Back 33

A long chain of volcanic islands

Front 34

faults

Back 34

Large breaks in rock layers

Front 35

Transform fault

Back 35

A fault that occurs at a transform plate boundary

Front 36

Focus

Back 36

Where an earthquake starts

Front 37

epicentre

Back 37

The point on the Earth's surface directly above the focus

Front 38

Seismology

Back 38

The study of earthquakes and seismic waves

Front 39

Surface waves (L-waves)

Back 39

Seismic waves that ripple along Earth's surface

Front 40

Primary waves (Waves (P-waves)

Back 40

A type of seismic wave that travels at 6km/s through Earth's crust, causing the ground to move in the direction of the waves motion

Front 41

Composite volcanoes

Back 41

Cone shaped, near subduction zones, explosive reuptions, thick lava

Front 42

Rift eruptions

Back 42

Occurs at ridges where plates separate, not very explosive but lots of magma

Front 43

Shield volcanoes

Back 43

Flat shield shaped, near hot spots, less explosive, thinner fast lava

Front 44

Ocean-continental plate convergence

Back 44

Oceanic plate subducts under the continental plat, forming a trench and mountain ranges

Volcanoes can form and earthquakes can occur

Front 45

Oceanic-oceanic plate convergence

Back 45

Cooler denser plate subducts under the less dense plate. May produce a volcanic island arc

Front 46

Continental-Continental plate convergence

Back 46

Edges fold and crumple, forming mountain ranges