Earth’s Surface Earth’s Surface

ErosionErosion

VocabularyVocabulary

ErosionErosion- - the process the process that wears that wears down and down and carries carries away rocks away rocks and soiland soil

ErosionErosion Gravity acts as a Gravity acts as a force of erosion by force of erosion by causing a mass causing a mass movementmovement•Mass movement-Mass movement- a a process that moves process that moves sediment down a sediment down a hillhill

There are 4 ways a There are 4 ways a mass movement may mass movement may occuroccur

Mass MovementMass Movement

Landslide-Landslide- a rapid a rapid movement of movement of large large amounts of amounts of rock and rock and soilsoil

Mass MovementMass Movement

Mudflow-Mudflow- a a rapid rapid downhill downhill movement of movement of a mixture of a mixture of water, rock water, rock and soiland soil

Mass MovementMass Movement

Slump-Slump- mass of mass of rock and soil rock and soil suddenly slips suddenly slips down a slopedown a slope• This is This is different from different from a landslide a landslide because it because it comes down in comes down in one large massone large mass

Mass MovementMass Movement

Creep-Creep- a very a very slow movement slow movement of rock and of rock and soilsoil•Usually creeps Usually creeps cause objects cause objects to sit at to sit at unusual anglesunusual angles

Water ErosionWater Erosion

StreamStream- a channel along which water - a channel along which water continually flowscontinually flows

RiverRiver- a large stream usually forming - a large stream usually forming from several streams flowing togetherfrom several streams flowing together

Features of StreamsFeatures of Streams

Flood Plain-Flood Plain- a flat area along a a flat area along a stream that is entirely covered only stream that is entirely covered only during times of floodsduring times of floods

MeanderMeander- the winding and bending of - the winding and bending of a stream as it erodes the landa stream as it erodes the land• Only older streams do thisOnly older streams do this

Oxbow Lake-Oxbow Lake- when sediment builds up, when sediment builds up, cutting off the meander from the cutting off the meander from the rest of the river, causing a rest of the river, causing a separate, curved lakeseparate, curved lake

Water ErosionWater Erosion

Fast moving Fast moving rivers that rivers that are straight are straight and narrow cut and narrow cut steep slopes steep slopes and create a and create a V-shaped V-shaped valleyvalley•Example- Example- Grand CanyonGrand Canyon

Grand CanyonGrand Canyon

Water ErosionWater Erosion

WaterfallWaterfall- a - a river cuts river cuts through soft through soft rock faster than rock faster than hard rock hard rock • Example- Niagara Example- Niagara FallsFalls

Niagara FallsNiagara Falls

Groundwater ErosionGroundwater Erosion

A form of chemical erosionA form of chemical erosion Makes caves and sinkholes Makes caves and sinkholes •CAVECAVE- limestone erodes away, - limestone erodes away, leaving behind a dry narrow leaving behind a dry narrow passagepassage

•SINKHOLESINKHOLE- weakened limestone - weakened limestone where the entire portion of where the entire portion of the ground suddenly collapsesthe ground suddenly collapses

Glacial ErosionGlacial Erosion

Glaciers erode Glaciers erode land in 2 waysland in 2 ways• Plucking-Plucking- as a as a glacier flows glacier flows over land it over land it picks up rockspicks up rocks

• Abrasion-Abrasion- gauges gauges and scratches in and scratches in rocks as a rocks as a glacier drags glacier drags across landacross land

Causes large, Causes large, bowl shaped bowl shaped valleys called valleys called cirquescirques

Cuts U-shaped Cuts U-shaped valleys in valleys in landformslandforms

May leave behind May leave behind large, cold large, cold glacial lakesglacial lakes

Wind ErosionWind Erosion DeflationDeflation- wind picks up and carries away - wind picks up and carries away small particlessmall particles• The faster the wind, the larger the The faster the wind, the larger the particles it can carryparticles it can carry

Example- Sand dunesExample- Sand dunes