geosphere defonitions Flashcards
Bauxite
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.
chemical weathering
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
constructive plate boundary
This occurs where convection currents in the upper mantle are
diverging, forcing the plates apart. Magma rises through the
gap, creating new oceanic crust.
convection
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.
convection currents
A circulation pattern in which warmer low-density material rises
and cooler high-density material sinks.
convergence plate boundary
Two or more tectonic plates move together. See destructive
plate boundary
core
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.
crust
The outer layer of the Earth. May be continental or oceanic,
and comprise igneous, metamorphic or sedimentary rocks.
destructive plate boundary
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.
district heating scheme
A network of pipes used to deliver heat (hot water or steam)
from the point of generation to an end user
divergence plate boundary
Two or more tectonic plates move apart. See constructive plate
boundary.
earthquake magnitude
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.
extrusive rock
Any rock derived from magma that flows onto the Earth’s
surface as lava or explodes violently into the atmosphere
fault
A fracture in rock due to stresses from a tectonic event.
fold mountains
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
frictional heat
A force opposite the direction of movement due to the rubbing
of surfaces in contact. The rubbing generates heat energy.
geothermal energy
The energy stored in the form of heat below the Earth’s
surface
geothermal gradient
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.
gravitational contraction
The collapse of gas and dust to form stars, planets and other
objects, under gravitational attraction.
gravitational potential energy,
When an object is above the Earth’s surface it has GPE.
Gravitational contraction resulted in the GPE being converted
to heat energy.
greenhouse gas
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.
ground source heat pump
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
hydrothermal vent,
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.
intrusive rock,
Rock formed from magma that cools and solidifies with the
Earth’s crust, ie does not reach the surface
laterite
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
kinetic energy
The energy an object possesses because of its motion.
lava,
Molten rock generated by geothermal energy and expelled
through fractures in the crust or via a volcanic eruption
leaching
The movement of dissolved substances with percolating water
in soil.
magma,
Hot fluid or semi-fluid material present below or within the
Earth’s crust.
mantle
Lies between the crust and outer core. Composed of magma
(semi-molten rock).
metallic mineral
A mineral is a solid, naturally occurring, inorganic substance. A
metallic mineral is one that contains one or more metallic
elements.
ocean trench
A geological structure which occurs undersea along the
boundary of a tectonic plate, specifically along subduction
zones.
open castmining,
The removal of mineral resources from the Earth’s surface
through large holes or pits
ore,
A naturally occurring solid material from which a metal or
valuable mineral can be extracted profitably.
overburden
Waste rock and soil overlying a mineral deposit that must be
removed before extraction of the mineral can take place.
particulates
Particulate matter includes all solid and liquid particles
suspended in air, for example dust, pollen, soot, smoke, liquid
droplets.
percolation,
The movement of water through soil by gravity and capillary
action
plate boundary,
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).
plate tectonics
A scientific theory describing the large-scale motion of plates of
crust and upper mantle.
radioactive decay
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
rift valley
Forms when two continental plates diverge, causing stretching
and fracturing of the crust. The land between the faults
collapses into a deep, wide valley.
runoff,
The flow of water over land as surface water
smelting
A process by which metal is obtained from its ore by heating it
beyond the melting point.
subduction zone
The point at which an oceanic plate is forced underneath a
continental plate at a destructive plate boundary
superheating,
The heating of a liquid, under pressure, to a temperature
higher than its boiling point, without actually boiling.
tailings
