Download - Agents of erosion and deposition

AGENTS OF EROSION AND

DEPOSITION

Chapter 12

12-1 Shoreline Erosion and Deposition Wave Energy

Wave Trains○ Waves move in

groups at regular intervals away from their source

○ When water gets shallow they change form and break Increased height and

closely spaced

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Wave Trains○ Wave Period

The interval between braking waves

Usually between 10-20 seconds long


Pounding Surf○ Waves have enough

energy to break rock ○ Pick up loose sand

and wears down coastal rock

○ Moves material

12-1 Shoreline Erosion and Deposition Wave Deposits

Beaches○ Any area of shoreline

made up of material deposited by waves

○ Colors and textures can varyDepends on source

of material


Wave angle○ Movement of sand

depends on wave angle

○ Perpendicular to the shore moves the sand in a zigzag pattern


Offshore Deposits○ Longshore current

Movement of water near or parallel to the shoreline

○ SandbarUnderwater ridge of

sand, gravel, or shells

○ Barrier SpitExposed sandbars

that connect

12-1 Shoreline Erosion and Deposition Wave Erosion

Sea Cliffs○ Form when waves

erode and undercut rock

○ Produce steep slopes○ Rate depends on

material


Sea Stacks○ Offshore columns of

resistant rock○ Were once part of

mainland Sea Arches

○ Continued erosion of a sea cave


Sea Cave○ Waves that cut holes

in rock along a cliffHeadland

○ Finger-shaped projection on a shoreline

Wave-cut Terrace○ Sea cliff that is worn

back to a level platform

12-2 Wind Erosion and Deposition Process of Wind

ErosionSaltation

○ The movement of sand-sized particles by a skipping and bouncing action

○ Happens in the direction the wind is blowing

12-2 Wind Erosion and Deposition Process of Wind

ErosionDeflation

○ The lifting and removal of fine sediment by wind

○ Leaves behind larger rock fragmentsDesert pavement

12-2 Wind Erosion and Deposition Wind Erosion and

DepositionAbrasion

○ The grinding and wearing down of rock surfaces by other rock or sand particles

○ Occurs in areas of strong winds and loose sand

○ Will erode, smooth, and polish rocks

12-2 Wind Erosion and Deposition Wind-Deposited

MaterialsDunes

○ Mounds of wind deposited sand

○ Wind slows down when it hits plants or rocks

○ Will drop heavier material


MaterialDunes

○ Move in the direction of the prevailing winds

○ Usually have a sloping side and a steep sideSlip face

- Steep side where material falls


MaterialLoess

○ Deposit of fine-grained sediment

○ Feels like talcum powder

○ Usually found far from their source

○ Great for crops

12-3 Erosion and Deposition by Ice Glaciers

An mass of moving ice

Erode, move, and deposit large amounts of rock material

Form in areas where snow is year round○ Weight of snow

compacts snow into ice crystals


Alpine Glaciers○ Forms in mountains○ Valley glacier

Form in valleys originally created by stream erosion

Flow slowly downhillCreate broad U-

shaped valleys


Continental Glaciers○ Spread across

continents○ Continental Ice Sheet

Huge continuous mass of ice

Continue to get larger over time


Ice Shelves○ Area where ice is

attached to the ice sheet but rests on open water

○ Will create icebergs when pieces break off


Icebergs○ Large pieces of ice

that break off and drift into the ocean

○ Mostly under water○ Calving

Process of production


Movement○ Ice that builds up will

move downhill○ Thickness of ice and

steepness of slope will determine how fast it moves


Crevasses○ A large crack that

forms where the glacier picks up speed or flows over a high point

○ Ice cannot stretch quickly and cracks

12-3 Erosion and Deposition by Ice