weathering and erosion Flashcards
what is weathering
breaking rocks into smaller pieces
what does mechanical weathering involve
breaking rocks without changing the chemical composition
what happens in ice wedging
water trapped in rocks freezes and expands, forcing the rocks apart
what can also cause mechanical weathering
plants
how do plants cause mechanical weathering
as their roots grow and put pressure on rocks, cracks widen and rock fragments may fall off
what does chemical weathering involve
water, air, and other substances reacting with the minerals in the rock
what are in plant roots that can cause chemical weathering
acids
what do the acids in plants do
they can react with the minerals in rocks
water and carbon dioxide combine to form what
carbonic acid
what does carbonic acid react with
minerals such as calcite and limestone
what occurs when metal is exposed to water
oxidation
how rapidy weathering occurs depends on what
the climate
where does chemical weathering occur slowly
in a desert
why does chemical weathering occur more slowly in a desert
lack of moisture
low temps in polar regions keep what to a minimum
chemical weathering
whenever freezing and thawing alternate what becomes an important form of weathering
mechanical weathering
what is the rate of weathering
how fast a rock breaks down
what affects the rate of weathering
rock comp, amount of exposure, climate, and topography
what is rock comp
what minerals make up the rock determines the rate at which it weathers
quartz is a harder mineraal so what is it resistant to
chemical and mechanical weathering
calcite is a softer mineral so what happens easily to it
chemical weathering
the more weathering processes that occursm what also happens more
the more it weathers
if you increase the sa of a rock, what will happen to the weathering rate
also increses
what has the biggest effect on the rate of weathering
rainfall and the freezing and thawing produced by alternating cold and hot weather
what climates have slow weathering
hot, dry and cold
what climates have more chemcal weathering
warm and humid
if you increase the altitude of a climate, what happens to the weathering
mechanical weathering is more likely
how do potholes in streets get larger over time
weathering, erosion, and deposition
what is mechanical weathering
physically breaking rock without changing the chemical comp
what is abrasion
grinding away rock particles as they rub or bounce against each other
what moves around rocks
water, ice, wind and gravity
what are some examples of biological weathering
animals burrowing and plants roots
what is chemical weathering
breaking rocks through chemical changesw
what is the best climate for chemical weathering
moist and warm
what is hydrolysis
when minerals change in water
what is oxidation
when metals combine with water
what dissolves in water to make carbonic acids
caarbon dioxide
what do living organinisms have that dissolves rocks
acids in weak roots
what kind of rain dissolves rock
acid rain
what is better for gravestones, granite or limestone
granite because its igneous
whats a meander
loop-like bends in the river
where are meanders found
rivers on flat land
what is the oxbow lake
a meander that has been cut off from the river
when do boulders deposit on a stream
firstwh
when do the smallest particles deposit on a stream
last
where does water go fastest on a meander
on the outer edge
what happens to the outer edge as water speeds up
eroision
where is water slowest on a meander
inner edge
what happens to the inner edge as water slows down
deposition
what settles faster, larger or smaller particles
larger
what happpens to the very small particles in a meander
they may remain suspended n the water indefinitely
what settles faster, round or flat particles
rounder
what is plucking
rocks freeze to the glacier and moves it
what is abrasion in glacial erosion
rocks in glaciers scratch bed rock
what is tll
unsorted glacial deposits
what is moraine
till deposited at the edge of a glacier
what are erratics
random boulders
what are striations
parallel scratches in bedrock
whats faster rivers flowing on a steep slope or rivers flowing on a flat slope
step slope
what happens in waterfalls
softer rocks erode and harder rocks remain
whats a flood plain
rivers that spread out when on flat land
what would happen if the river flooded on flood plains
the land would be covered
what major erosion can gravity cause
landslides, mudslides, slumps, and creeps
whats the most destructive cause of gravity
landslides
what are landslides
when rock and soil slide down a slope
what are mudslides
a downward flow of water, rock and soil
when do mudslides usually occur
after heavy rain
whats a slump
rock and soil slip in one large chunk
whats a creep
slowfall of rock and soil
whats deflation
when wind picks up loose particles (low spots)
what does the formation of sand dunes depend on
amount of speed, sand, and direction of wind and vegitation
whats a glacier
large mass of ice
what are valley glaciers
long and narrow
where do valley glaciers typically form
high in the mountains
what are continental glaicers
ice caps, cover alot of land
what is soil
weathered down rock material and organism matter
what is soil made up of
rock particles, minerals, decayed organic minerals, air and water
what is humus
a dark organic mineral found in soil made from he decayed remains of plants and animals
what is bedrock
soild, unweathered rock that lies beneath the oil
whats a soil profile
cross sections in which layers of the soil and bedrock beneath the soil can be seen
what are layers of soil and bedrock called
horizions
what are decomposers
the organisms that break the remains of dead organisms into smaller peices and digest them with chemicals
