Unit 4 Vocabulary
Chapter 8
1.) Magma – molten rock
2.) Plate Tectonics – Earth’s lithosphere is
divided into plates, most of which are in
constant motion.
3.) Tectonic Cycle – the sum of the processes
that build up and break down the lithosphere.
4.) Subduction – the process of one plate
passing under another plate
5.) Volcano – a vent in Earth’s surface that emits
ash, gases, and molten lava.
6.) Divergent Plate Boundary – plates move
away from each other
7.) Seafloor Spreading – creates new lithosphere
and brings important elements such as copper,
lead, and silver to the surface of Earth.
8.) Convergent Plate Boundary – where plates
move toward one another and collide
9.) Transform Fault Boundary – when plates
move sideways past each other.
10.) Fault – a fracture in rock across which there
is movement
11.) Earthquakes – occur when the rocks of the
lithosphere rupture unexpectedly along a fault.
12.) Seismic Activity – fault zones where
earthquakes are common
13.) Epicenter – the exact point on the surface of
the Earth directly above the location where the
rock ruptures (focus).
14.) Rock Cycle – the constant formation and
destruction of rock.
15.) Fractures – cracks that occur in any kind of
rock.
16.) Physical Weathering – the mechanical
breakdown or rocks and minerals.
17.) Chemical Weathering – the breakdown of
rock and minerals by chemical reactions.
18.) Acid Precipitation – when sulfur dioxide
reacts with water vapor in the atmosphere to
form sulfuric acid which creates this.
19.) Acid Rain – see acid precipitation
20.) Erosion – the physical removal of rock
fragments (sediment, soil, rock, and other
particles) from a landscape or ecosystem.
21.) Deposition – the accumulation or
depositing of eroded material such as sediment,
rock fragments, or soil.
22.) Soil – a mix of geologic and organic
components.
23.) Parent Material – the rock material
underlying it from which its inorganic
components are derived.
24.) Horizons – layers with distinct developed
characteristics.
25.) Topsoil – mixed either naturally or by
human agricultural practices
26.) Cation Exchange Capacity (CEC) – the ability
of a particular soil to absorb and release cations.
27.) Base Saturation – a measure of the
proportion of soil bases to soil acids, expressed
as a precentage
28.) Soil Degradation – the loss of some or all of
the ability of soils to support plant growth.
29.) Crustal Abundance – the average
concentration of an element in the crust.
Chapter 9
1.) Aquifers – groundwater exists in the
multitude of small spaces found within
permeable layers of rock and sediment.
2.) Unconfined Aquifer – water can easily flow in
and out of an aquifer
3.) Confined Aquifer – has an impermeable, or
confining, layer that impedes water flow to or
from the aquifer.
4.) Water Table – the uppermost level at which
the water in a given area fully saturates the rock
or soil.
5.) Groundwater Recharge – the input process
that water from precipitation can percolate
through the soil and work its way into an
aquifer.
6.) Springs – water from some aquifers naturally
percolates up to the ground surface.
7.) Artesian Well – drilling a hole into a confined
aquifer releases the pressure on the water,
allowing it to burst out of the aquifer and rise up
in the well.
8.) Cone of Depression – an area where there is
no longer any groundwater, due to the water
being rapidly withdrawn
9.) Saltwater Intrusion – with the adjacent salt
water is able to infiltrate the area of rapid
pumping, making the water in the wells salty.
10.) Floodplain – the excess water spreads onto
the land adjacent to the river.
11.) Oligotrophic – lakes that have low
productivity due to low amounts of nutrients
such as phosphorus and nitrogen in the water.
12.) Mesotrophic – lakes with moderate levels of
productivity
13.) Eutrophic – lakes with high levels of
productivity.
14.) Impermeable Surfaces – surfaces that do
not allow water penetration
15.) Levee – an enlarged bank built up on each
side of the river.
16.) Dikes – typically built to prevent ocean
waters from flooding adjacent land.
17.) Dam – a barrier that runs across a river or
stream to control the flow of water.
18.) Reservoir – water that is stored behind the
dam in a large body of water.
19.) Fish Ladders – built like a set of stairs with
water flowing over them.
20.) Aquaducts – canals or ditches used to carry
water from one location to another.
21.) Desalination – the process of removing the
salt from salt water to obtain freshwater.
22.) Hydroponic Agriculture – the cultivation of
crop plants under greenhouse conditions with
their roots immersed in a nutrient – rich
solution, but no soil.