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33 terms

Earth science unit 3

erosion & deposition.
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outwash plain
melt water at end of glacier sorts and carries smaller sediment from glacier, makes layers.
kettle lakes
chunks of ice break off as glacier retreats, outwash sediment then builds up around. ice melts then makes lake.
erratic
large boulder different than bedrock
moraine
unsorted, sub rounded material dropped by a glacier when glacier melts.
drumlin
mounded moraine (glacial till) in shape of upside down spoon.
shows direction of movement, steeper slope on side glacier came from.
deposition by mass movement
sediment at bottom of cliff/slope is poorly sorted
deposition by wind
are layered and cross bedded, sand grains are highly sorted, rounded, frosted and pitted. wind direction controls shape of sand dunes.
shoreline deposition
spit deposits in bays used to tell direction of longshore current. break walls and jetties used to block current and cause deposition.
erosion
involves transport. agents are wind, water, glaciers, and mass movement.
gravity
most driving force behind all agents of erosion
stream erosion
most responsible for shaping land.
high velocity
= more erosion
watershed
where all the lands area water drains into a stream
tributary
small stream or river that flows into a larger stream or river
divide
elevated land that divides one watershed or drainage basin from another
headwaters
the region where water first accumulates to supply a stream
delta
the triangular deposit that forms where a stream enters into a large body of water
flood plain
flat area that extends out from a streams bank and is covered by excess water during times of flooding
cut bank
outside stream or river where erosion occurs and higher velocity. deep
point bar
inside stream or river where deposition occurs and lower velocity. shallow
oxbow lake
part of lake that eventually dries up
levees
forming sediment mounds
potential energy
stored energy (available to do work)
kinetic energy
energy in motion (doing work)
streams
have highest potential energy at highest elevation
highest kinetic energy
with highest velocity, stream carrying capacity ( stream load )
carry capacity
total amount of sediment a stream carries
bed load
consists of sand, pebbles and cobbles
suspended
particles small enough to be held up by the turbulence of a streams moving water
dissolved load
material is carried by solution
stream deposition
process by which sediments are released, dropped or settled from an erosional system. caused by loss of kinetic energy (velocity) in agent of erosion
wind erosion
dominates on arid (dry) regions, best sorter grains become frosted and pitted.
glacial erosion
occurs where it is cold (high elevation, high latitude)