Lecture 4

Question 1

Tectonic plates

Answer 1

Large subdivisions in the crust of the planet, which are generally in motion over long geological time scales

Question 2

Plate tectonics

Answer 2

The study of movement of tectonic plates

Question 3

Fault

Answer 3

Major fracture in the continuity of two regions of rocks

Question 4

Oceanic crust

Answer 4

One of the two major divisions in types of tectonic plates:
-Mainly found under oceans
-Relatively young in geological timescale

Question 5

Continental crust

Answer 5

The other major division in types of tectonic plates:
-Varying ages but relatively older than oceanic crusts
-Generally found out of water

Question 6

Asthenosphere

Answer 6

Denser, weaker layer below the lithosphere
Temperatures are hot enough that rock behaves like a liquid (temps increase towards the core)

Question 7

Lithosphere

Answer 7

The solid, outer part of Earth

Question 8

Convection current

Answer 8

Moves tectonic plates
- current that flows up from the core of the Earth and circulate under the asthenosphere

Question 9

Ridges

Answer 9

1st process that convection currents move tectonic plates through: creation of new plate at ridges (push)
-pushes existing plate away from the ridge

Question 10

Subduction zones

Answer 10

2nd process that convection currents move tectonic plates through: destruction of plates at subduction zones (pull)

Question 11

Push-pull

Answer 11

Process driving plate tectonics

Question 12

Divergent boundary

Answer 12

Occurs when 2 tectonic plates move away from each other

Question 13

Magnetic pole reversals

Answer 13

The locations of magnetic north and south generated by Earth’s magnetic field switch over time

Question 14

Convergent boundary

Answer 14

When 2 plates come together

Question 15

Transform boundary

Answer 15

Places where plates slide sideways past each other

Question 16

Sea floor spreading

Answer 16

The process of tectonic plates moving apart at divergent boundaries

Question 17

Hydrothermal sea vent

Answer 17

Weak point in the sea floor where water and minerals heated geothermally enter the ocean
-commonly found along divergent boundaries
-may have played an important role in the evolution of life

Question 18

Rift valley

Answer 18

A divergent boundary which forms on land

Question 19

Oceanic trench

Answer 19

Formed when oceanic crust meets continental crust at a divergent boundary
(steep depressions in the deepest parts of the ocean)

Question 20

Transform faults

Answer 20

When two plates slide past each other, results in large characteristic faults

Question 21

Elastic rebound theory

Answer 21

Earthquakes occur because plates at transform boundaries cannot move continuously and energy builds up at the transform fault, until energy stored is released all at once in a sudden movement of the 2 plates

Question 22

Angle of insolation

Answer 22

Angle at which sunlight hits the planet (differs across the planet)

Question 23

Albedo

Answer 23

Reflectivity of a surface

Question 24

Igneous

Answer 24

Type of rock found in crust: formed from the cooling of molten rock from the mantle

Question 25

Sedimentary

Answer 25

Type of rock found in crust: formed from the pieces of other rocks and sometimes organic material

Question 26

Metamorphic

Answer 26

Type of rock found in the crust: minerals that have been changed from their original form through intense heat and pressure

Question 27

Landform

Answer 27

Natural feature of the physical landscape of the Earth

Question 28

Weathering

Answer 28

Disintegration (weakening) and decomposition (break down) of rock
3 types: physical, chemical and biological

Question 29

Physical weathering

Answer 29

Mechanical break-up of rock
Occurs in the presence and absence of terrestrial life
Caused by water, ice, physical contact between 2 sets of rocks

Question 30

Chemical weathering

Answer 30

Mineral breakdown caused by chemical reaction
Also occurred before terrestrial life

Question 31

Biological weathering

Answer 31

Only occurred on land once life became terrestrial
Can seem mechanical (tree roots breaking up rock)
Can also seem chemical (lichen using acids to break down rock)
Difference from other forms of weathering: must have a biological component

Question 32

Erosion

Answer 32

Material which has been weakened or broken down through weathering is moved from its original location

Question 33

The rock cycle

Answer 33

The conversion of one rock type to another is continuous