geosphere defonitions

Question 1

Bauxite

Answer 1

Bauxite is the most common ore of aluminium. Extraction of aluminium metal takes place in three main stages: mining of bauxite ore, refining the ore to recover alumina, and smelting alumina to produce aluminium.

Question 2

chemical weathering

Answer 2

Rainwater reacts with mineral grains in rocks to form new
minerals (clays) and soluble salts. These chemical reactions
occur particularly when the rainwater is slightly acidic

Question 3

constructive plate boundary

Answer 3

This occurs where convection currents in the upper mantle are
diverging, forcing the plates apart. Magma rises through the
gap, creating new oceanic crust.

Question 4

convection

Answer 4

Convection is the movement of particles through a substance, transporting their heat energy from hotter areas to cooler areas. Conduction however, doesn’t necessarily involve particles moving. Instead energy is passed from one particle to another upon contact, transferring heat.

Question 5

convection currents

Answer 5

A circulation pattern in which warmer low-density material rises
and cooler high-density material sinks.

Question 6

convergence plate boundary

Answer 6

Two or more tectonic plates move together. See destructive
plate boundary

Question 7

core

Answer 7

The Earth’s inner core is solid, composed of an iron-nickel
alloy, and surrounded by a liquid outer core of molten iron and
nickel.

Question 8

crust

Answer 8

The outer layer of the Earth. May be continental or oceanic,
and comprise igneous, metamorphic or sedimentary rocks.

Question 9

destructive plate boundary

Answer 9

This occurs where convection currents in the upper mantle are
converging, forcing the plates above to move towards each
other. The denser plate subducts below the less dense plate,
resulting in a net loss of crust.

Question 10

district heating scheme

Answer 10

A network of pipes used to deliver heat (hot water or steam)
from the point of generation to an end user

Question 11

divergence plate boundary

Answer 11

Two or more tectonic plates move apart. See constructive plate
boundary.

Question 12

earthquake magnitude

Answer 12

Earthquakes generate vibrations, known as seismic waves.
The magnitude or size of an earthquake can be estimated from
the amplitude and length of a seismic wave.

Question 13

extrusive rock

Answer 13

Any rock derived from magma that flows onto the Earth’s
surface as lava or explodes violently into the atmosphere

Question 14

fault

Answer 14

A fracture in rock due to stresses from a tectonic event.

Question 15

fold mountains

Answer 15

Occur near convergent plate boundaries. Subduction of one
plate under another results in layers of sediments lying at the
junction being crumpled and folded, appearing above sea level
as a range of mountains

Question 16

frictional heat

Answer 16

A force opposite the direction of movement due to the rubbing
of surfaces in contact. The rubbing generates heat energy.

Question 17

geothermal energy

Answer 17

The energy stored in the form of heat below the Earth’s
surface

Question 18

geothermal gradient

Answer 18

The rate of increasing temperature vs increasing depth in the
Earth’s interior. Away from tectonic plates, temperature
increases by around 2·5 °C per 100 m depth.

Question 19

gravitational contraction

Answer 19

The collapse of gas and dust to form stars, planets and other
objects, under gravitational attraction.

Question 20

gravitational potential energy,

Answer 20

When an object is above the Earth’s surface it has GPE.
Gravitational contraction resulted in the GPE being converted
to heat energy.

Question 21

greenhouse gas

Answer 21

A gas that traps heat in the atmosphere. Natural GHGs include
water vapour, carbon dioxide, methane, and nitrous oxide.
Anthropogenic GHGs include enhanced levels of the natural
GHGs plus ozone and halocarbons.

Question 22

ground source heat pump

Answer 22

Pipes buried below ground, with a circulating mixture of water
and antifreeze, absorb heat from the ground which can be
removed using a heat exchanger and used to heat a building
or to provide hot water

Question 23

hydrothermal vent,

Answer 23

Forms as a result of volcanic activity on the sea floor. Water
seeps down through cracks in the crust and comes into contact
with magma in the upper mantle, dissolving metals and
minerals as it becomes super-heated. The super-heated water
erupts as a geyser from the hydrothermal vent, with the
dissolved metals and minerals precipitating out on contact with
cold seawater and forming a chimney around the vent.

Question 24

intrusive rock,

Answer 24

Rock formed from magma that cools and solidifies with the
Earth’s crust, ie does not reach the surface

Question 25

laterite

Answer 25

A soil formed under conditions of high temperature and heavy
rainfall with alternate wet and dry periods, which leads to
leaching of soil, leaving only oxides of iron and aluminium

Question 26

kinetic energy

Answer 26

The energy an object possesses because of its motion.

Question 27

lava,

Answer 27

Molten rock generated by geothermal energy and expelled
through fractures in the crust or via a volcanic eruption

Question 28

leaching

Answer 28

The movement of dissolved substances with percolating water
in soil.

Question 29

magma,

Answer 29

Hot fluid or semi-fluid material present below or within the
Earth’s crust.

Question 30

mantle

Answer 30

Lies between the crust and outer core. Composed of magma
(semi-molten rock).

Question 31

metallic mineral

Answer 31

A mineral is a solid, naturally occurring, inorganic substance. A
metallic mineral is one that contains one or more metallic
elements.

Question 32

ocean trench

Answer 32

A geological structure which occurs undersea along the
boundary of a tectonic plate, specifically along subduction
zones.

Question 33

open castmining,

Answer 33

The removal of mineral resources from the Earth’s surface
through large holes or pits

Question 34

ore,

Answer 34

A naturally occurring solid material from which a metal or
valuable mineral can be extracted profitably.

Question 35

overburden

Answer 35

Waste rock and soil overlying a mineral deposit that must be
removed before extraction of the mineral can take place.

Question 36

particulates

Answer 36

Particulate matter includes all solid and liquid particles
suspended in air, for example dust, pollen, soot, smoke, liquid
droplets.

Question 37

percolation,

Answer 37

The movement of water through soil by gravity and capillary
action

Question 38

plate boundary,

Answer 38

A boundary between two or more plates, which can be moving
towards each other (convergent), away from each other
(divergent), or past each other (transform).

Question 39

plate tectonics

Answer 39

A scientific theory describing the large-scale motion of plates of
crust and upper mantle.

Question 40

radioactive decay

Answer 40

The process by which an unstable atomic nucleus loses
energy by emitting radiation in the form of particles or
electromagnetic waves, thereby transitioning towards a more
stable state

Question 41

rift valley

Answer 41

Forms when two continental plates diverge, causing stretching
and fracturing of the crust. The land between the faults
collapses into a deep, wide valley.

Question 42

runoff,

Answer 42

The flow of water over land as surface water

Question 43

smelting

Answer 43

A process by which metal is obtained from its ore by heating it
beyond the melting point.

Question 44

subduction zone

Answer 44

The point at which an oceanic plate is forced underneath a
continental plate at a destructive plate boundary

Question 45

superheating,

Answer 45

The heating of a liquid, under pressure, to a temperature
higher than its boiling point, without actually boiling.

Question 46

tailings